Biodiversity and Zoogeography of the Polychaeta (Annelida) in the deep Weddell Sea (Southern Ocean, Antarctica) and adjacent deep-sea basins

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1 Biodiversity and Zoogeography of the Polychaeta (Annelida) in the deep Weddell Sea (Southern Ocean, Antarctica) and adjacent deep-sea basins Dissertation zur Erlangung des Grades eines Doktors der Naturwissenschaften der Fakultät für Biologie und Biotechnologie der Ruhr-Universität Bochum angefertigt im Lehrstuhl für Evolutionsökologie und Biodiversität der Tiere vorgelegt von Myriam Schüller aus Aachen Bochum 2007

2 Biodiversität und Zoogeographie der Polychaeta (Annelida) des Weddell Meeres (Süd Ozean, Antarktis) und angrenzender Tiefseebecken

3 The most exciting phrase to hear in science, the one that heralds new discoveries, is not EUREKA! (I found it!) but THAT S FUNNY Isaak Asimov US science fiction novelist & scholar ( ) photo: Ampharetidae from the Southern Ocean, S. Kaiser Title photo: Polychaete samples from the expedition DIVA II, Schüller & Brenke, 2005

4 Erklärung Hiermit erkläre ich, dass ich die Arbeit selbständig verfasst und bei keiner anderen Fakultät eingereicht und dass ich keine anderen als die angegebenen Hilfsmittel verwendet habe. Es handelt sich bei der heute von mir eingereichten Dissertation um fünf in Wort und Bild völlig übereinstimmende Exemplare. Weiterhin erkläre ich, dass digitale Abbildungen nur die originalen Daten enthalten und in keinem Fall inhaltsverändernde Bildbearbeitung vorgenommen wurde. Bochum, den Myriam Schüller

5 INDEX iv Index 1 Introduction The Southern Ocean Introduction to the Polychaeta Polychaete morphology Ampharetidae MALMGREN Glyceridae GRUBE Goniadidae KINBERG Hesionidae GRUBE Nephtyidae GRUBE Nereididae JOHNSTON Opheliidae MALMGREN Sabellariidae JOHNSTON Scalibregmatidae MALMGREN Sphaerodoridae MALMGREN Syllidae GRUBE Terebellidae MALMGREN Trichobranchidae MALMGREN Polychaete ecology, reproduction and feeding strategies Ampharetidae MALMGREN Glyceridae GRUBE Goniadidae KINBERG Hesionidae GRUBE Nephtyidae GRUBE Nereididae JOHNSTON Opheliidae MALMGREN Sabellariidae JOHNSTON Scalibregmatidae MALMGREN Sphaerodoridae MALMGREN Syllidae GRUBE Terebellidae MALMGREN

6 INDEX v Trichobranchidae MALMGREN Polychaete systematics 19 2 Material and methods The expeditions ANDEEP I, II, and III: sampling and on-board treatment Taxonomic analyses Final sorting, identification, and labeling of species Description of new species Construction of identification keys Univariate and multivariate community analyses Species accumulation plots Standardization and transformation of sampling data Univariate biodiversity measures Similarity measures Comparison of EBS epi- and supranets Cluster analysis and MDS plotting Environmental factors and species sets explaining station similarities BIO-ENV BV Step Average Taxonomic Distinctness (AvTD) and Variations in Taxonomic Distinctness (VarTD) Reconstruction of vertical and global distribution patterns Vertical distribution patterns Global distribution patterns 32 3 Results Composition of polychaete communities Identification keys to selected species found during ANDEEP I-III Key to the Ampharetidae MALMGREN Glyceridae GRUBE Key to the Goniadidae KINBERG

7 INDEX vi Key to the Hesionidae GRUBE Key to the Nephtyidae GRUBE Key to the Nereididae JOHNSTON Key to the Opheliidae MALMGREN Sabellariidae JOHNSTON Key to the Scalibregmatidae MALMGREN Key to the Sphaerodoridae MALMGREN Key to the Syllidae GRUBE Key to the Terebellidae MALMGREN Key to the Trichobranchidae MALMGREN Descriptions of new species Ampharetidae MALMGREN Anobothrus pseudoampharete sp.n Hesionidae GRUBE Amphiduros serratus sp.n Micropodarke cylindripalpata sp.n Ophiodromus calligocervix sp.n Parasyllidea delicata sp.n Opheliidae MALMGREN Ammotrypanella MCINTOSH Ammotrypanella arctica MCINTOSH Ammotrypanella cirrosa sp.n Ammotrypanella mcintoshi sp.n Ammotrypanella princessa sp.n Ophelina ÖRSTED Ophelina ammotrypanella sp.n Ophelina robusta sp.n Scalibregmatidae MALMGREN Pseudoscalibregma papilia sp.n Sphaerodoridae MALMGREN Ephesiella hartmanae sp.n Sphaerodoropsis HARTMAN & FAUCHALD

8 INDEX vii Sphaerodoropsis distincta sp.n Sphaerodoropsis maculata sp.n Sphaerodoropsis simplex sp.n Univariate and multivariate community analyses Analysis of the epi- and supranet Species richness and biodiversity Species richness (Margalef s Index) Biodiversity and Evenness Clustering and Multi Dimensional Scaling (MDS) ANDEEP I-III ANDEEP I/II ANDEEP III Correlation of polychaete communities to environmental data (BIO-ENV) Correlation of species to stations similarities (BV Step) Average Taxonomic Distinctness (AvTD) and Variation in Taxonomic Distinctness (VarTD) Zoogeography Vertical distribution patterns in the Southern Ocean Global distribution patterns Discussion Efficiency of the gear and methods used for sampling Polychaete abundance and family composition Species identification, composition and descriptions of new species Species composition of families Descriptions of new species Ampharetidae MALMGREN Hesionidae GRUBE Opheliidae MALMGREN Scalibregmatidae MALMGREN Sphaerodoridae MALMGREN

9 INDEX viii 4.4 Polychaete diversity in the Southern Ocean Similarities between sampling areas Influence of environmental factors and species on similarities Taxonomic diversity Zoogeography and vertical distribution Origin of the Southern Ocean deep-sea fauna Vertical distribution Global distribution patterns Summary Zusammenfassung References Appendix Figures Tables Acknowledges Lebenslauf 247

10 INTRODUCTION 1 1 Introduction During the austral summers of 2002 and 2005 the expeditions ANDEEP I-III took place to conduct one of the first thorough surveys concerning the faunal composition of the deep Weddell and Scotia Seas. Transects starting south of South Africa, crossing the Weddell Sea and the Drake Passage, and ending at the western coast of the Antarctic Peninsula were sampled with several gear gathering faunal as well as geological data. Since then specialists of different scientific backgrounds have analyzed the samples and put together a complex puzzle of taxonomy, systematics, zoogeography, and ecology of the epi- and infaunal communities in the deep Southern Ocean. As part of this approach, the polychaetes sampled with an epibenthic sledge (EBS) during ANDEEP I-III are focus of this study. Based on taxonomic analysis, a characterization of the polychaete communities in the deep Southern Ocean and the global zoogeography of the sampled species is achieved on a scale that is unique in its outline to date. Due to the high number of individuals in the samples, an analysis on a taxonomic level lower than family is only done for thirteen families, belonging to four different orders, respectively suborders, which are all common representatives of the deep-sea polychaete fauna world wide. These are the Ampharetidae, Sabellariidae, Terebellidae, Trichobranchidae (Terebellida), Glyceridae, Goniadidae, Nephtyidae, Sphaerodoridae (Glyceriformia), Hesionidae, Nereididae, Syllidae (Nereidiformia), Opheliidae, and Scalibregmatidae (Opheliida). The study includes a detailed taxonomic analysis of these families, analyses of their community structure, and descriptions of new species. In combination with biodiversity measures and ecological analyses, this approach will substantially contribute to our knowledge about the deep-sea benthos in the Southern Ocean. In addition, the global distribution patterns of the polychaete species sampled are reconstructed. The results are used to give insight into possible ways of distribution of polychaetes in the Southern Ocean and adjacent deep-sea basins, and contribute to the answers about the colonization history of the Southern Ocean deep sea.

11 INTRODUCTION The Southern Ocean The Southern Ocean markedly differs from other oceans in that it lacks continental borders. Rather, its water masses are isolated from the other world oceans by circulatory systems and water fronts resulting in steep physical gradients at the transition zones. The uniqueness of its oceanography (Dayton et al., 1994) and the continent of Antarctica have been subject to extensive research during the last centuries. Antarctica is permanently covered with ice. While the ice is restricted to the landmasses and coastal waters during the austral summer, great parts of the Southern Ocean are covered with thick masses of ice during the austral winter. Constant low temperatures, the almost circular outline of the continent and prevailing westerly winds lead to the formation of an unique ocean system. The air temperatures around Antarctica seldomly rise above 2 C and water temperature near the continent lie between -2 and -1 C throughout the year (Brey & Clarke, 1993; Knox & Lowry, 1977; Pearse et al., 1991). The Southern Ocean undergoes a steady eastwardly moving circumpolar current (White & Peterson, 1996; Knox & Lowry, 1977) resulting from prevailing westerly winds (West-Wind Drift) (Knox & Lowry, 1977) (Fig. 1). The Circumpolar Current has been stable in position since its formation in the Cenozoic (Barker & Thomas, 2004) and is today the strongest ocean current known (Barker & Thomas, 2004; Gnanadesikan & Hallberg, 2000). Near the Antarctic continent east and south-east winds result in a westerly water flow (East-Wind-Drift) that, when meeting the east coast of the Antarctic Peninsula flows north to the Scotia Ridge and then eastwards across the South Atlantic (Weddell-Sea-Drift) (Knox & Lowry, 1977). In addition, cold and dense surface water flows northwards where it meets less dense southerly flowing subantarctic water. At around S these two water masses collide and the denser Antarctic water sinks below to form the Antarctic Convergence. The Antarctic Convergence is characterized by steep gradients in salinity and temperature (Deacon, 1933, 1937; Mackintosh, 1946; Moore et al., 1999). Close to the continent the sea ice formation results in high density water that sinks below 4000 m and forms the Antarctic bottom water (Adkins et al., 2002; Stössel & Kim, 1998). Meanwhile, deep water from higher latitudes flows south

12 INTRODUCTION 3 to rise to the surface at around 60 S (Antarctic Divergence) (Knox & Lowry, 1977; Matsumoto et al., 2001). Fig. 1: Current systems in the Southern Ocean (modified after Berkman, 1992) While the cold temperatures and water currents lead to an isolation of the Southern Ocean that is also partly reflected in the Antarctic shelf fauna (Brandt, 1992; Dayton et al., 1994; Hilbig, 2004), the Antarctic deep sea shows ecological characters similar to other deep-sea basins of the world. It is characterized by the total lack of light, very slow bottom currents, and a constant temperature of about C (Fütterer et al., 2003). Nevertheless some unusual characters can be found. Because of the heavy ice cover of Antarctica the continent is pushed downwards. Therefore the shelf, though narrow at most sites, reaches down to 600 m, even 800 m in the Ross Sea. This is about twice as deep as in other oceans. Abyssal plains are first found below 3700 m (Knox & Lowry, 1977). Still the ecological similarities between the Southern Ocean deep sea and lower latitude deep seas imply that the deep-sea basins around Antarctica might not be

13 INTRODUCTION 4 as faunally isolated as the Antarctic shelf. Some invertebrate genera and species found in the Southern Ocean have also been found in deep-sea basins world wide (e.g., Brandt, 1991; Hilbig, 2004). 1.2 Introduction to the Polychaeta The polychaetes are one of the most common macroinfaunal invertebrate taxa in oceans world wide. Aside from the benthos, polychaetes are also found in the interstitial, in the water column (holopelagic forms and pelagic larvae), and as parasites. They occur in shallow waters as well as in the deep sea. This unique variability and flexibility in life strategies, together with their high abundance makes polychaetes one of the most important invertebrate groups in marine biodiversity and monitoring studies. The taxon Polychaeta is very large. Over 85 different families are distinguished to date (Fauchald & Rouse, 1997), only a small percentage of them being well studied. The different polychaete families are characterized by a high variability in body shape. While some families can easily be classified to lower taxonomic levels (e.g., Scalibregmatidae, Sphaerodoridae), others show only a low number of distinct characters (e.g., Cirratulidae, Maldanidae). In addition, many taxa are very speciose (e.g., Spionidae). Thus species identifications can be problematic, sometimes resulting in an insufficient resolution of the taxonomy of some taxa. As complex and confusing as the taxonomy is the phylogeny. Many monospecific genera exist and species are often shifted between genera and even families.the group of the polychaetes is too large for a thorough molecular study of the whole taxon. Single attempts have been made to date to resolve the relationships within single genera or families. A cladistic analysis based on morphologic characters has been presented by Rouse and Fauchald (1997). But still the dataset used for this study is not complete some information on characters for several families is missing so that the result only gives a trend in polychaete cladistics (Rouse & Fauchald, 1997).

14 INTRODUCTION Polychaete morphology Fauchald (1977), Hartmann-Schröder (1996), and Fauchald & Rouse (1997) give excellent summaries of polychaete morphology and taxonomy. All subsequent information about the morphology of polychaetes in general and selected families is, unless stated otherwise, taken from these studies. The polychaete worms follow the annelid bauplan. They are characterized by either homonomous or heteronomous segmentation along the whole body. The presegmental region consists of the prostomium and the peristomium. The prostomium can bear several antennae, palps (which can also derive from the peristomium, e.g., buccal tentacles), eyes, and nuchal organs (chemosensory organs). The peristomium, which, as well as the prostomium, always lacks chaetae, often bears peristomial cirri. Ventrally, between the prostomium and the peristomium, the mouth is located. Subsequent to the presegmental region is the segmented trunk. Each segment usually carries parapodia and chaetae (therefore called chaetiger) as well as segmentally arranged internal organs. The first chaetigers often carry tentacular cirri arising from reduced parapodia. Those segments can either be recognized as separate segments or are fused with each other and sometimes the peristomium (cephalization) so that the original number is hard to determine. The overall number of chaetigers usually differs within members of one species. The terminal segment (postsegmental region), which is always achaetous, is the pygidium with the anus and possible anal cirri. The pygidium includes the growth zone where new segments derive. The final body shape of each polychaete species is very variable. Many species look highly complex due to the presence of more than one body region with differently shaped chaetigers (heteronomous segmentation). Also the head region can be strongly modified as adaptation to different life forms (e.g., life in tubes, in the sediment, pelagic) and food sources. The plesiomorphic parapodial form consists of two rami (biramous parapodium), the neuropodium (ventral) and the notopodium (dorsal). The two rami can be similar or distinctly different in size and shape. If one ramus is reduced in size (subbiramous parapodium) or lacking (uniramous parapodium) it is always the notopodium. The parapodia are used for crawling and swimming. In burrowing and tube dwelling forms

15 INTRODUCTION 6 they are often reduced to rudiments that do not hinder the animal s movement through the sediment, or function as anchors in tubes. Each neuro-/ notopodium is classically characterized by the presence of a neuro-/ notopodial lobe that carries the chaetae and a ventral/ dorsal cirrus. The lobes are often supported by one or more internal strong chaetae, the aciculae. If lobes are formed as welts or ridges without aciculae they are often regarded as tori. Most tori are characterized by the presence of hooks or unicini. In addition to the parapodial lobes, pre- or postchaetal lobes and additional ligules, as well as variably shaped branchiae, can be present. Ventral and dorsal cirri are very variable in shape in different taxa and on different regions of the body. They can also be lacking. An important character in polychaete taxonomy is the shape of the chaetae. They can be simple or compound, smooth or serrated, falcigerous or spinigerous, internally with or without structure, capillaries or spines, and much more. Some chaetae are so strongly modified that they are hardly recognized as such, e.g., uncini (chaetae modified to hooks) or palae in the Terebellomorpha. Within one individual, several different chaetae types can occur, either in different body regions or within one parapodium. The presence or absence of chaetae can be an important taxonomic character as well. The polychaeta operate skin respiration. In order to enlarge the respiratory surface, branchiae can be present. These are often found dorsally on the anterior body region or attached to the parapodia. The internal structure of the Polychaeta is characterized by the presence of longitudinal, ring and parapodial muscles, a rope-ladder nervous system, a more or less closed circulatory system, a gut consisting of pharynx (often eversible and armed with jaws) and sometimes proventricle, middle gut and end gut, segmental proto- or metanephridia, and gonads. Reductions and variations in structure and number of these features are common. In the following short summaries of the bauplan for the thirteen families focused on in this study are given. As for the general polychaete morphology, the information is mainly taken from Fauchald (1977), Hartmann-Schröder (1996), and Fauchald & Rouse (1997), additional citations are marked as such. The summaries contribute to the understanding of the taxonomic classification of the species sampled and the descriptions of new species.

16 INTRODUCTION Ampharetidae MALMGREN 1866 The prostomium of the Ampharetidae is rather small but variable in shape, the peristomium is limited to the lips and mouth. Antennae are missing, palps are present as well developed buccal tentacles. These are retractable. They are everted through an eversion of the lip-like structure on which they are located. Nuchal organs are small and indistinct. The first and second segments are fused to the head and achaetous. The third segment can bear large, robust chaetae, called paleae (Day, 1964, Holthe, 1986). The segmented trunk consists of two regions, the thorax and the abdomen. The parapodia of the thorax bear chaetae in the notopodia and uncini (chaetae modified to hooks) in the neuropodia. The notopodia of the abdomen are reduced, notopodial lobes can still be present. Dorsal and ventral cirri are lacking throughout. The pygidium sometimes bears abdominal cirri. An important taxonomic character of the Ampharetidae is the number and arrangement of the branchiae on the anterior segments. Up to four pairs can be present that are arranged in transverse rows across the dorsum of the anterior segments. Additionally, the number of thoracic setigers is species specific Glyceridae GRUBE 1850 The prostomium is ringed externally, strongly prolonged and tapering, and bears a pair of antennae and palps at its tip. The peristomium is limited to the lips. The glycerids are characterized by homonomous segmentation with well developed parapodia. The parapodia are either biramous or uniramous, often with highly differentiated post- and prechaetal lobes. Dorsal and ventral cirri, as well as one pair of anal cirri are present. Branchiae can be present. The eversible pharynx bears a multitude of papillae of one or two kinds and is tipped by four jaws supported by ailerons.

17 INTRODUCTION Goniadidae KINBERG 1866 The prostomium is externally ringed and tapers to a blunt tip with two antennae and palps. The peristomium is limited to the lips. The anterior parapodia of the homonomous trunk consist of well developed neuropodia, the notopodia are reduced to the dorsal cirri. In median and posterior parapodia both rami are of similar development. One pair of anal cirri is present, branchiae are lacking. The pharynx always bears various pharyngeal organs. These can either be of few kinds or characteristically differentiated in variety and size. The arrangement of the pharyngeal papillae is considered a species character. At the tip of the pharynx a circlet of two macrognaths and two arcs of micrognaths are found forming a complex jaw apparatus (Hartman, 1950) Hesionidae GRUBE 1850 The prostomium is well developed and bears 2-3 antennae and usually one pair of ventral palps. Large eyes, consisting of a disinct lense are often present as well as apparent nuchal organs on the posterior margin of the prostomium. The peristomium is limited to the lips. The hesionids are homonomously segmented, several anterior segments are fused and cephalized. The dorsal and ventral cirri of these segments are prolonged to form up to eight pairs of tentacular cirri. Chaetae are usually missing in these segments. The following segments are uniramous or biramous, subbiramous parapodia are also reported. Ventral and dorsal cirri are usually well developed. While the notochaetae are simple throughout, the neurochaetae are composite. The pygidium bears one pair of anal cirri. Jaws may be present, branchiae are always lacking Nephtyidae GRUBE 1850 The prostomium is quadrangular or pentagonal with one pair of lateral antennae and one pair of ventrolateral palps. The peristomium is limited to the lips. Nuchal organs are

18 INTRODUCTION 9 present, often indistinct. The first segment is smaller than the subsequent with smaller parapodia. One or two pairs of tentacular cirri are present. All parapodia are biramous, well developed, with dorsal and ventral cirri and complex pre- and postchaetal lobes. The two rami are often widely separated from each other, resulting in a square cross section that is characteristical for the Nephtyidae. Ventrally on the notopodia branchiae are present that reach into the space between the noto- and neuropodia, curled inward (e.g., Aglaophamus KINBERG 1866) or outward (e.g., Nephtys CUVIER 1817) The chaetae are simple, but characteristically ornamented. One single anal cirrus is present medially on the pygidium. The pharynx is armed with buccal papillae and one pair of lateral jaws, the papillae of which are of major importance in taxonomic studies Nereididae JOHNSTON 1865 The prostomium is inversely T-shaped, and in small species often diamond shaped. It bears a pair of frontal antennae and a pair of usually large articulated palps. The peristomium is limited to the lips. Nuchal organs are present. The first indistinct segment carries tentactular cirri (usually four pairs, sometimes only two or three). The biramous parapodia are well developed with both dorsal and ventral cirri. The notopodia additionally have flattened ligules. The chaetae are exclusively composite. For Hediste MALMGREN 1867 heavily fused chaetae are reported that appear simple at first view (Breton et al., 2003). The pygidium bears a pair of anal cirri. Branchiae are absent. The pharynx is armed with prominent lateral jaws. Terminal papillae are lacking while the outer surface of the pharynx is covered with papillae. Additionally, the presence and shape of paragnaths is an important distinguishing character for the Nereididae Opheliidae MALMGREN 1867 Opheliidae are fusi-form polychaetes, the body might be prolonged with a ventral groove. The prostomium is usually conical and sometimes carries a papilliform distal palpode. Antennae and palps are absent. The peristomium is limited to the lips. A pair

19 INTRODUCTION 10 of distinct eversible nuchal organs is present laterally on the prostomium. The mouth is present as a transverse slit ventrally on the first chaetiger rather than between the prostomium and the peristomium. All chaetigers are similar in shape, the parapodia are biramous but reduced in size. The chaetae are exclusively capillaries with various ornamentations. Branchiae, when present, are associated with the upper end of the parapodia. They consist of single filaments only. Dorsal and ventral cirri are lacking. The pygidium bears multiple cirri, or may be hood-shaped with internal or marginal cirri. The presence of anal tubes is common. The pharynx is unarmed Sabellariidae JOHNSTON 1865 The prostomium is fused to the peristomium and often only visible as a median keel. The peristomium is visible as lips, usually covered by the first two chaetigers (the first of which is fused to the head). The chaetae of these chaetigers are modified to form an operculum. Antennae are missing while palps and nuchal organs are present. The notopodia are short and cylindrical, the neuropodia are tori. Dorsal and ventral cirri are absent, flattened branchiae are present dorsally. The Sabellariidae are characterized by chaetal inversion, abdominal uncini are notopodial while thoracic ones are neuropodial. Chaetae types are variously ornamented capillaries, spines and uncini Scalibregmatidae MALMGREN 1867 The prostomium of the Scalibregmatidae is truncate or t-shaped. Antennae and palps are absent. The peristomium is well developed, forming a ring around the prostomium. Anterior segments might be characteristically expanded, or the body is maggot-like. The parapodia are biramous, fully developed with rather short rami. Dorsal and ventral cirri are reported for some species (Blake, 1981; Schüller & Hilbig, 2007). The presence of branchiae is a common trait. The chaetae observed are capillaries, furcate chaetae and sometimes anterior acicular spines.

20 INTRODUCTION Sphaerodoridae MALMGREN 1867 The prostomium is either free or fused to peristomium. The peristomium is limited to the lips. Paired lateral antennae and a median antenna are present in addition to a ventral pair of palps. Nuchal organs are also observed. The first segment of the homonomously segmented trunk is indistinct. The uniramous parapodia are well developed with distinct neuropodia and ventral cirri. Branchiae are absent. The dorsum of the body is densely covered by small (microtubercles) and numerous rows of large tubercles (macrotubercle). The most lateral rows of these marcotubercles are assumed to be modified dorsal cirri. The tubercles can be sessil or with a short stem; their number and shape are strong taxonomic characters. The chaetae are either compound falcigers or ornamented capillaries. Some taxa bear anterior spines Syllidae GRUBE 1850 The prostomium is truncate bearing three antennae and a pair of unarticulated, more or less fused palps. The peristomium is limited to the lips. Nuchal organs are present. The first segment differs from the following by lacking chaetae, two pairs of tentacular cirri are present instead. The parapodia are usually biramous, the notopodia being less developed than the neuropodia. Dorsal and ventral cirri are present in most subfamilies, the Autolytinae lack ventral cirri. The cirri vary in length and shape, they are either smooth or articulated. One pair of anal cirri is present. Branchiae are absent. The chaetae are composite with variously structured appendages. In addition, one or two simple chaetae can be present per parapodium. The anterior digestive tract is equipped with a muscular proventricle that is unique for this family in its form. The cells of the proventricle are arranged in distinct rows whose approximal number is fixed for each species. The pharynx is often armed with one or more teeth.

21 INTRODUCTION Terebellidae MALMGREN 1867 The prostomium, peristomium and anterior segments are fused. The peristomium and the anterior segments form an extended upper lip. Antennae are lacking and numerous grooved tentacular palps emerge at the margin between pro- and peristomium. These palps are not retractable into the mouth, in contrast to that of the Ampharetidae. Nuchal organs can be present or absent. The body is separated into two regions. The thorax is characterized by biramous parapodia of which the notopodia carry ornamented capillaries, the neuropodia uncini. In the abdominal segments the notopodia are strongly reduced. Tentacular, dorsal and ventral cirri are absent. Branchiae of various types can be present dorsally in anterior chaetigers Trichobranchidae MALMGREN 1866 The pro- and peristomium are fused, the peristomium forms an extended lip similar to that of the Terebellidae. Antennae are absent, palps are present as multiple buccal tentacles. These are grooved and originate from the prostomial edge. Nuchal organs have been observed in some taxa. The first segment is fused to the head and achaetous. The following thoracic segments have biramous parapodia with chaetae carrying notopodia and uncinal neuropodia. One or several of the anterior segments can bear neuropodial bent spines. In abdominal segments, the notopodia are strongly reduced. While the thoracic uncini are long-handled, that of the abdomen are short-handled. Ventral, dorsal and anal cirri are lacking. Branchiae are either present as two to three groups of single filaments or as a single branchia which may be cirriform or consist of four lamellate lobes dorsally on anterior chaetigers.

22 INTRODUCTION Polychaete ecology, reproduction and feeding strategies As mentioned above the Polychaeta have occupied most ecological niches found in marine environments (Ushakov, 1974). Most species are benthic forms (epi- or infauna) but also pelagic (e.g., Alciopidae, Tomopteridae) (Ushakov, 1974; Fauchald, 1977), parasitic (e.g., some Eunicidae) (Clark, 1956; Pettibone, 1957), and commensalist forms (e.g., some Syllidae, Nereididae, or Polynoidae associated with clams, sponges, star fish, or tunicates) (Hartman, 1936; Licher, 1999; Rosbaczylo & Canete, 1993) are known. As benthic samples are the base for the presented study the focus is laid upon benthic forms in the following. Benthic polychaetes have evolved in high variability. They cover a size range from few micrometers (e.g., some Syllidae) to several centimeters (e.g., some Ampharetidae) or even meters (e.g., some Eunicidae) in length. As variable as form and size are the ecological niches they occupy. E.g., interstitial forms, burrowers (e.g., Opheliidae, Scalibregmatidae, Capitellidae), tube dwellers (e.g., Ampharetidae, Sabellariidae, many Terebellidae and Trichobranchidae), and epibenthic vagile forms (e.g., Eunicidae, Glyceridae, Hesionidae, Nereididae, Phyllodocidae) are observed. This flexibility is obviously not achieved by variability in form and size alone, but also by adaptations in physiology, such as reproduction and feeding strategies. Feeding strategies range from omnivorous and carnivorous hunters, selective and nonselective deposit feeders, to suspension feeders. Even in chemoautotrophic environments such as hydrothermal vents, cold seeps, and whale falls, polychaetes play a dominant role. Many forms have been found living in symbiosis with chemoautotroph bacteria (e.g., Alvinella pompejana DESBRUYÈRES AND LAUBIER 1980 living in symbiosis with Proteobacteria spec. (Campbell et al., 2001)). The reproduction in polychaetes is also widely variable. Though most polychaetes have separate sexes, parthenogenesis and hermaphroditism have been reported in some species (e.g., the sphaerodorid species Ephesiella mixta (FAUCHALD 1974) (Ushakov, 1974)). Many species can additionally switch between generative and vegetative reproduction. During vegetative reproduction the polychaetes abandon certain parts of their body and replace those lost segments by regeneration of new segments. Fragmentation and collateral budding are also very common. Vegetative reproduction

23 INTRODUCTION 14 enables the polychaetes to react fast to changes in environment (e.g., sudden food input). Generative reproduction can occur in various ways, too. The most common way is that the female releases the eggs into the water column (either through the nephridium or by rupture of the body wall) where they are fertilised by the sperms of the male. A second way is that only one part of the body becomes fertile (epitokous) and is released from the otherwise sterile (atokous) polychaete (schizogamy). The epitokous parts of both sexes then ascend to the water surface, mate and die afterwards while the atokous parts live on as before. Sometimes the whole animals becomes epitokous (epigamy). A well known family for epitoky are the Syllidae. They are characterized by the formation of numerous fertile epitokous parts in the posterior derivation zone, the so called stolons (e.g., Rouse & Pleijel, 2006). The separation of atokous infertile stages and epitokous fertile stages is consequently limited to free living forms, it is not reported for tubedwellers. Originally polychaetes have pelagic larvae (trochophorae). These are either planktotrophic or lecithotrophic. For some species both larval forms have been reported (e.g., Tharyx marioni (ST. JOSEPH 1894) (Cazaux, 1972; Dales, 1951; Gibbs, 1971) or Nereis pelagica LINNÉ 1761 (Herpin, 1925; Wilson, 1932)). Vivipary (Ushakov, 1974), external gestation (e.g., some Syllidae (Licher, 1999)) and brooding have also been observed. Although a general idea of the variability in reproduction and feeding of the Polychaeta exists little is known about actual strategies of the different families. In the following a short overview of the knowledge to date concerning the families treated in detail in this study is given Ampharetidae MALMGREN 1866 The Ampharetidae are tube-building suspension feeders. They are often rather large forms (few millimeters up to several centimeters) that are common on soft bottom and hard substrates of all depths, especially in the deep sea (Cosson-Saradin et al., 1998;

24 INTRODUCTION 15 Fauchald, 1977; Hartman, 1966; 1967; 1978; Hilbig, 2004). Forms living in symbiosis with chemoautotrophic bacteria have been observed. Ampharetidae have pelagic larvae (e.g., Melinna cristata (SARS 1851)), free-swimming juveniles (e.g., Ampharete grubei MALMGREN 1865) or are active brooders (such as Hobsonia florida (HARTMAN 1951)) (Wilson, 1991). Their reproduction is mainly generative Glyceridae GRUBE 1850 The Glyceridae are vagile forms that live on and in soft, sandy and muddy substrate. They are suspectively carnivorous hunters (Fauchald, 1977). Their well developed jaw apparatus enables them to feed on smaller invertebrates. Little is known about their reproduction. It is probably generative with pelagic (species of Glycera SAVIGNY 1818) or non-swimming larvae. Also epitoky is reported for species of Glycera with species bearing prolonged epitokous setae (Arwidsson, 1899; Ehlers, 1868; Fage & Legendre, 1927; Hartman, 1950; Wilson, 1991) Goniadidae KINBERG 1866 The feeding strategies of the Goniadidae are still unresolved. While species of this family have been regarded carnivorous predators (Ehlers, 1868; McIntosh, 1910), Stolte (1932) suspected them to be detritus feeders. Their reproductive strategies are very variable. Epitoky is reported (Hartman, 1950). The presence of epitokous setae is thus still questionable. They are not reported in Ophioglycera VERRILL 1885 but might be present in some species of Goniada AUDOUIN & EDWARDS 1834 (Hartman, 1950). Glycinde armigera MOORE 1911 has lecithotrophic larvae, Goniada emerita AUDOUIN & EDWARDS 1834 planktotrophic (Blake, 1975; Cazaux, 1972; Wilson, 1991).

25 INTRODUCTION Hesionidae GRUBE 1850 The Hesionidae are of medium size, usually around a few millimeters long. They are mainly epibenthic and vagile. Most species prefer primary and secondary hard substrates (Fauchald, 1977), but also several pelagic or commensalist forms are known. The presence of papillae and small chitinized jaws in some species suggests omnivorous feeding. Their reproduction strategies include free-swimming planktotrophic and lecitotrophic larvae (such as species of Gyptis MARION & BOBRETZKY 1875 and Ophiodromus SARS 1862), free-swimming juveniles (species of Hesionides FRIEDRICH 1937), and encapsulation of planktotrophic larvae and juveniles in gelatinous capsules (Microphthalmus MECZNIKOW 1865) (Blake, 1975; Haaland & Schram, 1983; Treadwell, 1898; Westheide, 1967; 1970; Wilson, 1991) Nephtyidae GRUBE 1850 The Nephtyidae are vagile forms of the benthic community. They prefer soft or sandy substrates that they can crawl on or burrow in. They mainly occur in shallower depths; deep-sea species have also been reported (Hartman, 1950). Their feeding strategy is propably similar to that of the Hesionidae since only some horny papillae are present instead of jaws. Their reproduction strategies include epitoky. Prolonged epitokous chaetae and enlarged parapodial lobes are reported for some species (Augener, 1912; Fage & Legendre, 1927). The larval stages are mostly planktotrophic (Hartman, 1950; Wilson, 1991) Nereididae JOHNSTON 1865 The Nereididae are easily the best known polychaetes. They are most common in marine environments of all depths but also freshwater penetration is reported (Ushakov, 1974; Fauchald, 1977). Their size ranges from few millimeters to several centimeters. As omnivorous vagile forms they feed on algae and hunt small invertebrates.

26 INTRODUCTION 17 Their reproduction is mainly generative with pelagic larvae. These can be planktotrophic (e.g., Nereis grubei (KINBERG 1866), Perinereis cultrifera (GRUBE 1840)) or lecithotrophic (e.g., Nereis diversicolor O. F. MÜLLER 1776, Platynereis bicanaliculata (BAIRD 1863)) (Blake, 1975; Cazaux, 1969; Dales, 1950; Reish, 1954; 1957). Free-swimming juvelines and brooders with tubes and direct development are also known (Wilson, 1991). For some species several reproduction strategies are reported (e.g., Platynereis dumerilii (AUDOUIN & MILNE EDWARDS 1833), Nereis pelagica LINNÉ 1761) (Wilson, 1991). In addition, epitoky is common for the Nereididae, the epitokous forms are then called Heteronereis (e.g., Clark, 1961; Rouse & Pleijel, 2006) Opheliidae MALMGREN 1867 The Ophelilidae are burrowing deposit feeders. They are very common in sandy and muddy bottoms of all depths (Fauchald, 1977). During reproduction pelagic larvae are produced that are either planktotrophic or lecithotrophic (Wilson, 1991). For Ophelina bicornis SAVIGNY 1818 both variants are reported (Riser, 1987; Wilson, 1948) Sabellariidae JOHNSTON 1865 The body of the Sabellariidae is completely adapted to life in a tube (Fauchald, 1977). They are the only known reef-builders (Schäfer, 1972) among polychaetes. Exclusively plantotrophic larvae are known to date. Reproductive strategies are, however, only reported for few genera (Rouse & Pleijel, 2006; Wilson, 1991) Scalibregmatidae MALMGREN 1867 Their similarity in body shape to the Opheliidae suggests similar feeding and reproduction strategies. The Scalibregmatidae are deposit feeders that burrow in the

27 INTRODUCTION 18 sediment. Studies on their reproduction strategies are lacking, information about their larval stages is not available Sphaerodoridae MALMGREN 1867 The Sphaerodoridae are small, vagile hunters, probably omnivorous. They are exclusively epibenthic and are most common on sandy and muddy bottoms in deep waters. Some records from shallow hard bottoms exist. Generative reproduction with demersal larvae seems to be the most common reproduction strategy, but hermaphroditism and the occurance of lecithotrophic, suprabenthic larvae are suggested in some species (Fauchald, 1974; 1977) Syllidae GRUBE 1850 Similar to the Sphaerodoridae the Syllidae are also relatively small, fragile, and vagile polychaetes. Their food supposedly consists of small algae and protozoans, although larger forms might be able to feed on meiobenthic invertebrates. They occupy a great variety of ecological niches including commensalism with sponges and other invertebrates offering cavern-like structures, and parasitism (Licher, 1999), but an interstitial and benthic way of living in waters of all depths is but the most common. The Syllidae are known for a huge flexibility in reproductive strategies (Wilson, 1991). Besides generative reproduction (schizogamy, and epigamy with stolonization), the reproduction by collateral budding is reported. Brooding, vivipary and external gestation are very common for the Syllidae (e.g, Exogone OERSTED 1845, Sphaerosyllis CLAPAREDE 1863) (Cazaux, 1972; Westheide, 1974). In addition, cases of hermaphroditism are reported (Licher, 1999).

28 INTRODUCTION Terebellidae MALMGREN 1867 The Terebellidae are tube-dwelling suspension feeders found in all environments (Fauchald, 1977). They are not completely restricted to living in their tubes and can leave them occasionally. The reproduction strategies of the Terebellidae are mainly generative reproduction with lecitotrophic pelagic larvae (e.g., Artacama proboscidea MALMGREN 1866 (Thorson, 1946)) or brooding. Direct development is also very common (Wilson, 1991) Trichobranchidae MALMGREN 1866 The Trichobranchidae are very similar to the Terebellidae and Ampharetidae. It is therefore proposed that their ecology, including feeding and reproduction strategies, are similar. Most species are represented in cold-water soft bottoms, especially in greater depths (Fauchald, 1977). Terebellides stroemi SARS 835 is reported to have gelatinous capsules and direct development (Thorson, 1946) Polychaete systematics Systematics in polychaetes is still unresolved and problematic. There is still controversy as to whether the taxon Polychaeta is monophyletic or paraphyletic within the Annelida (Kojima, 1998; Mc Hugh, 1997; Rouse & Fauchald, 1995; Westheide et al., 1999). There is evidence from molecular studies that the polychaetes are paraphyletic and that the Echiura, Pogonophora and Clitellata nest among them (Bleidorn et al., 2003a; 2003b; Jördens et al., 2004; Struck et al., 2002). In addition, the monophyly of the Annelida is in question to some extent. Westheide et al. (1999) give the most recent summary about the different approaches to solve the systematics of the Annelida and the position of the polychaetes. To date it is unknown what the basal and most ancient annelid looks like. Knowledge of this stem species would strongly benefit to determining the systematics of the

29 INTRODUCTION 20 Polychaeta in general (Rouse & Pleijel, 2003; Westheide et al. 1999). One hypothesis is that the most basal forms are simple-bodied taxa. This would lead to the assumption that the ancient annelids were mud-dwelling burrowers (Clark, 1964; 1969; Fauchald, 1974; Kojima, 1998) feeding on sediment. A second hypothesis expresses the idea of an epifaunal annelid with homonomous segmentation and biramous parapodia as the stem species (Conway Morris & Peel, 1995; Mc Hugh, 1997; Westheide, 1997). Within the Polychaeta, the position of the separate families is also largely unknown. This is due to the great size of this taxon (a particular problem for molecular studies), and also the fact that many families are only poorly studied. Many characters are not determined so that there is great lack of information for morphological systematics. As for the Annelida the most basal form of the polychaetes is unknown. It is again either a burrowing form (similar to Opheliidae or Questidae) or an aciculate, epifaunal form (Rouse & Pleijel, 2003). The most complete approach to date to bring some light into the relationships between the different families of the Polychaeta was presented in 1997 by Rouse and Fauchald. They presented a cladistic analysis on morphological data covering almost all polychaete groups then distinguished. Rouse and Pleijel (2006) give an excellent summary of this analysis including a discussion of the monophyly of different groups based on autapomorphies. Due to a lack of appropriate alternatives based either on morphological or molecular data sets, the tree originating from that study is used here as systematic background where needed (App.-Fig. 1). The dendrogram suggests a monophyletic taxon Polychaeta, with a sister taxon Clitellata, within the monophyletic Annelida. The most basal polychaetes here are the simple-bodied Scolecida such as Orbinidae, Opheliidae, and Maldanidae. Two sister taxa of the Scolecida are proposed, the vagile Aciculata consisting of the Phyllodocida and Eunicida, and the less motile, often tube-dwelling Canalipalpata with the Sabellida, Terebellida, and Spionida. In contrast to former classifications, such as that of Fauchald, 1977, the Sabellariidae are considered to be Sabellida instead of Terebellida (Rouse & Fauchald, 1997).

30 MATERIAL & METHODS 21 2 Material and methods 2.1 The expeditions ANDEEP I, II and III: sampling and on-board treatment The expeditions ANDEEP I and II took place from January 23 rd, 2002 to April 1 st, Starting from Punta Arenas, Chile, samples were taken in the Drake Passage, off Elephant Island, the Bransfield Strait, across the Weddell Sea, and off the South Sandwich Islands. In early 2005 (January 21 st to April 6 th ) the expedition ANDEEP III started in Cape Town, South Africa, to take further samples on a transect from South Africa to the eastern Weddell Sea, crossing the Weddell Sea to the Antarctic Peninsula, sampling also some sites near the South Orkney Islands, in the Drake Passage, and in the Bransfield Strait (Fig. 2). Fig. 2: Position of stations: ANDEEP I/II (white stations) and ANDEEP III (black stations). Map by A. Brandt Four different gears were deployed to sample the epifauna. This study is based on the samples taken by an epibenthic sledge (EBS) at 29 different stations (Tab. 1). The EBS was constructed at the Ruhr-University of Bochum, a detailed description of

31 MATERIAL & METHODS 22 construction and deployment is given by Brenke, The EBS consists of two nets, the epi- and the supranet, each 1 m wide (Fig. 3). During deployment, the EBS was trawled on the bottom for 10 minutes steaming time (speed approximately 1.0 Kn) as soon as it touched the ground. Then the ship was stopped and the EBS was hauled in with 0.5 m/s winch speed. The exact times when the EBS touched the ground, started to trawl, and left the ground again was determined by curve changes in the tension recorder protocol. This way the trawling distance and sampling area (trawling distance x EBS width [1.0 m]) could be determined with minimum error (Tab. 1). For optimal conservation for molecular methods the samples were immediately fixed in precooled 96 % ethanol and gradually transferred to 70 % ethanol within the subsequent 48 hours. After final fixation in 70 % ethanol, samples were partly sorted to higher taxonomic levels on board. After the end of the expeditions samples were shipped to the German Center for Marine Biodiversity Research (DZMB) in Wilhelmshaven and to the Zoological Museum, University of Hamburg where the sorting to higher taxa was completed. Then, the Polychaeta were transferred to the Ruhr-University of Bochum for final analyses. Fig. 3: Epibenthic sledge: model deployed during the expeditions ANDEEP I-III. Photo by M. Schüller & N. Brenke

32 MATERIAL & METHODS 23 Tab. 1: Station coordinates and trawling distances of the expeditions ANDEEP I-III station date latitude longitude location depth (m) 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'S 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'E 'E 'E 'E 'W 'E 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W 'W trawling distance (m) Ona Basin/ Drake Passage Ona Basin/ Drake Passage Elephant Island/ Drake Passage Central Weddell Sea Central Weddell Sea Central Weddell Sea Central Weddell Sea Central Weddell Sea South Sandwich Islands South Sandwich Islands South Africa/ South Atlantic South Africa/ South Atlantic Atlantic Sector of SO Eastern Weddell Sea Eastern Weddell Sea Eastern Weddell Sea Eastern Weddell Sea Transect eastern to central Weddell Sea Transect eastern to central Weddell Sea Transect eastern to central Weddell Sea Transect eastern to central Weddell Sea Central Weddell Sea Central Weddell Sea Central Weddell Sea South Orkney Islands South Orkney Islands Elephant Island/ Drake Passage King George Island King George Island

33 MATERIAL & METHODS Taxonomic analyses Final sorting, identification, and labeling of species Polychaete specimens were sorted to family level, the number of individuals per family was documented. The families Ampharetidae, Glyceridae, Goniadidae, Hesionidae, Nephtyidae, Nereididae, Opheliidae, Sabellariidae, Scalibregmatidae, Sphaeodoridae, Syllidae, Terebellidae, and Trichobranchidae were determined to species level. Specimens of different stations and different EBS nets were documented separately in species assemblage matrices. Specimens are stored in single vials in 70 % ethanol at the Ruhr-University of Bochum and will be transferred to the Zoological Museum, University of Hamburg after completion of the ANDEEP project. Identification of species took place mainly with help of the monographs and studies of Hartman, 1964, 1966, 1967, 1978, Fauchald, 1977, and Hartmann-Schröder & Rosenfeldt, 1988, 1989, 1990, 1991, For species not found in these works, original species descriptions were consulted. Species of questionable identity and new species were named by the lowest taxonomic level known plus chronological numbers. New species also found by Dr. B. Ebbe during former studies were named with Ebbe s denotation (pers. comments) plus the appendix BH to achieve constant labeling Description of new species Fifteen new species were described. The type material is stored at the Ruhr-University Bochum and will be transferred to Zoological Museum, Hamburg after publication of descriptions. For magnification of specimens a stereomicroscope type Olympus SZH 10 and a microscope type Olympus BX40 were used. Drawings were prepared with Rotring Rapidograph pens, sizes 0.25 mm and 0.18 mm. After completion, drawings were scanned (600 dpi, tiff files), digitally optimized, and labeled with Adobe Photoshop 7.0.

34 MATERIAL & METHODS Construction of identification keys Based on the sampled material and information from literature (e.g. Fauchald, 1977; Fauchald & Rouse, 1997; Hartmann-Schröder, 1996) identification keys were prepared. The keys include species found in the ANDEEP I-III material only. During construction of keys emphasis was laid upon identification by simple distinct characters that do not require complex preparation. 2.3 Univariate and multivariate community analyses Analyses of species data were made with Microsoft Office Excel and PRIMER v 6.1.6, a program designed for the analysis of biological data in biodiversity and monitoring studies (Clarke & Warwick, 2001) Species accumulation plots To find out if the sampling volume covers the maximum of expected species for the sampled area a species accumulation plot is drawn for all species of ANDEEP I-III. By means of UGE analyses (after Ugland, Gray & Ellingsen, 2003) a smoothed S curve based on 999 permutations is achieved. A rising curve indicates an undersampling of the area, meaning that not all species present have been collected. A graph converging to maximum values indicates that all species of the area are sampled Standardization and transformation of sampling data The sampling volume of all stations is different due to different trawling distances. Additionally, samples of ANDEEP I/II are incomplete, not all net samples are available for this study. Before similarity analyses, the species assemblage matrix of ANDEEP

35 MATERIAL & METHODS 26 I/II is therefore transformed into a presence/ absence matrix. The same applies to the combined matrix of ANDEEP I-III. The sample data of ANDEEP III are complete. Species abundance is standardized to 1000 m trawling distance and quantitative data are accomplished. Before the calculation of similarities fourth root transformation is applied to reduce the influence of the few very abundant species and increase that of the numerous rare species Univariate biodiversity measures For the data of ANDEEP III the Shannon Index was chosen as biodiversity measure: H = - i p i log (p i ), with log- base = e p i = N i /N total N i = number of individuals of species i N total = number of individuals per station This index relates the number of individuals of each species to the number of individuals of all species from one sample. It is the one most used in biodiversity studies and allows the comparison of this study to data from literature. Due to its high dependence on the sample volume it is not suitable for non-quantitative data. In addition, the Pielou s Evenness Index is calculated for ANDEEP III-samples: J = H / log S, with S = number of species per station The index describes how evenly individuals between the species of one station are distributed. It is based on the Shannon Index and underlies the same dependences. For the non-quantitative data of ANDEEP I-III the Margalef s Index for species richness is chosen: d = (S-1) / log N, with S = number of species per station N = number of individuals per station

36 MATERIAL & METHODS Similarity measures The similarities between different stations were measured with the Bray-Curtis Index: S jk = 100 (1 [ p i=1 y ij - y ik ] / [ p i=1(y ij + y ik )]), with y ij/k = ith species in the jth/ kth sample i = 1, 2, 3,, p It is the most used similarity measure in ecological studies. Its main characteristics are: 1.) S = 0 when there are no similarities and S = 100 when samples are identical 2.) Changes in scales (e.g., g mg) do not change the result 3.) The lack of a species in both samples compared does not change the result which is thus exclusively based on similarities 4.) For a presence/ absence matrix the Bray-Curtis Index equals the Sörensen Coefficient The index was applied to all ANDEEP matrices. For comparison of ecological data, differences between stations instead of similarities are measured by means of Euclidean distance: d jk = p i=1(y ij - y ik ) 2, with y ij/k = ith value in the jth/ kth sample i = 1, 2, 3,, p Comparison of EBS epi- and supranets To determine if samples of the epi- and supranet of each station are to be treated as different stations or as pseudoreplicates (results in a summation of the nets to a single abundance value per station) a one-way ANOSIM (ANalysis Of SIMilarities) with 999 permutations was carried out on the species resemblance matrix of ANDEEP III (abundances standardized to 1000 m trawling distance, 4 th root transformation). The

37 MATERIAL & METHODS 28 method compares the similarities (R) between nets of one station with that of different stations: R = (r B -r W )/(1/2M), with r B = average similarities of nets between stations r W = average similarities of nets within stations M = n(n-1)/2, with n = number of samples R = 1 expresses that nets of one station are more similar to each other than nets of different stations. R = 0 expresses the null hypothesis that no differences in similarities between the nets of one station and that of different stations exist. During permutation the sample labels are altered and random data matrices are constructed. The R values for these test-matrices are determined and compared to that of the original data. If the R value of the original data lies outside the range of all random values, the null hypothesis can be rejected with a significance level (p) of 1 to 999 (in case of 999 permutations), and p < 0.1 % Cluster analysis and MDS plotting Based on the Bray-Curtis resemblance matrices similarities and relations between different stations are visualized by clustering and multi dimensional plotting (MDS) (Clarke & Warwick, 2001). Cluster analysis was done hierarchically with group-average linkage, resulting in a dendrogram. This is done by first grouping the two most similar stations. A new resemblance matrix is now created. The similarity of the formed group to other stations equals the average of the similarities of the single stations of this group to other stations. Then again the most similar stations are grouped together, and so on. The x-axis of the resulting dendrogram presents the different groupings, the y-axis the percental similarities. Statistical significance of the groups is tested by a SIMPROF (similarity profile permutation) test and visualized by the shape of the branches. Drawn through branches are well, dotted branches weakly supported.

38 MATERIAL & METHODS 29 During MDS plotting, station similarities are visualized by relative distances in a multi dimensional space. A two dimensional space is chosen for this study. MDS plots are achieved by the following steps (compare Kruskal, 1964): 1. Construction of a random starting configuration on the dimensional space chosen 2. Construction of a Shepard diagram comparing the actual similarities of stations with that in the random diagram 3. Construction of a regression line in the Shepard diagram giving the line of minimal stress level between the actual similarities and the diagram distances 4. Calculation of the present stress level (expresses the differences between the actual similarities and diagram ordination) 5. Movement of ordination points towards the direction of decreasing stress 6. Repetition of steps 2 to 5 until no lower stress level can be achieved The stress level shows how well the similarities are mirrored by the ordination in the end. Stress levels below 0.1 are very good values, below 0.2 show potentially good results. Higher stress levels have to be treated with caution, they might indicate random ordinations Environmental factors and species sets explaining station similarities BIO-ENV Based on the assumption that stations with similar environments have similar species compositions, the resemblance matrices of these two descriptive factors can be correlated to each other by rank correlation coefficients. Coefficients are based on rankings of stations instead of total values because the resemblance matrices are calculated by different coefficients (species data: Bray-Curtis Index, ecological data: Euclidean distances).

39 MATERIAL & METHODS 30 For this study the Spearman coefficient is chosen: ρ = 1 6 / (N (N 2-1)) N i=1 (r i - -s i ) 2, with N = n (n-1) / 2 (n = number of samples) r i / s i = elements of resemblence matrices The Primer function BIO-ENV uses this coefficient to compare every possible combination of environmental factor sets to the species matrix. The sets resulting in the highest ρ-values present a likely explanation for found species community structures. Significance of the result is tested by a permutation test (RELATE with 99 permutations) based on the same procedure as the ANOSIM test explained above. The BIO-ENV method is applied to the data of ANDEEP I/II comparing species composition with sediment grain size, O 2 depth, and water depth BV Step On the lines of the BIO-ENV procedure species matrices can be compared to themselves to find the set of species dominating station similarities. Due to the huge data size the BV Step method is used. This method is also based on the Spearman coefficient. It first searches for the species resulting in the highest ρ-value; then stepwise adds further species, always in search of the maximum ρ-value for the sets, until no higher values can be achieved. The method is applied to the ANDEEP I-III species matrix reduced to species contributing a minimum of 4 % to any station. The starting point of the procedure was determined with six random variables and ten repetitions, the significance of the result is tested by a 99 permutation RELATE test.

40 MATERIAL & METHODS Average Taxonomic Distinctness (AvTD) and Variations in Taxonomic Distinctness (VarTD) The AvTD expresses the expected taxonomic distance between two randomly chosen different species. For presence/ absence matrices it is defined as: Δ + = [ i<j ω ij ] / [S (S-1) / 2], with ω ij = distance between the species i and j S = total number of species in the sample The VarTD [Λ + ] describes the expected variation of the actual taxonomic distances between two randomly chosen species and the AvTD: Λ + = [ i<j (ω ij -Δ + ) 2 ] / [S (S-1) / 2], with ω ij = distance between the species i and j S = total number of species in the sample In this study the AvTD and VarTD of the stations of ANDEEP I-III (presence/ absence matrix) are compared with a master list including all species found during the expeditions. The master list gives the expected values for the sampling area. It also functions as a systematic tree for the analysis. It assigns species to their according genera (with a taxonomic distance of 1) and genera to their according families (taxonomic distance of 2). The AvTDs and VarTDs of different stations are separately compared to those of the master list in funnel plots. Also shown is the 95 % significance range for the values. A combined analysis of both two values is shown in elliptic graphs. This comparison is advisable in case negative correlations between AvTD and VarTD at some stations exist.

41 MATERIAL & METHODS Reconstruction of vertical and global distribution patterns Vertical distribution patterns Vertical distribution patterns are reconstructed by dividing water depths into depth ranges of 1000 m each and marking the ranges in which the different species were found Global distribution patterns The global distribution of named species is reconstructed based on former records of species. Charts were created with the programs GEBCO and Adobe Photo Shop 7.0. For comparison of the distribution patterns within the families the global distribution was split into six categories: LR- locally restricted to certain areas within the Southern Ocean, SU- Subantarctic (south of 45 S), SA- also found in the southern Atlantic, SPalso found in the southern Pacific, SH- southern hemisphere, C- cosmopolitan. All records used for the construction of the global patterns are taken from the literature (Augener, 1912, 1932; Benham, 1921, 1927; Blake, 1981; Blankensteyn & Lana, 1986; Ehlers, 1897, 1900, 1901, 1908, 1912, 1913; Fauchald, 1972; Fauvel, 1916, 1936, 1941, 1951; Gillet & Dauvin, 2000; Gravier, 1906a, 1906b, 1906c, 1907a, 1907b, 1911a, 1911b; Grube, 1877; Hartley, 1985; Hartman, 1952, 1953, 1964, 1966, 1967, 1971, 1978; Hartman & Fauchald, 1971; Hartmann-Schröder, 1965, 1996; Hartmann-Schröder & Rosenfeldt, 1988, 1989, 1990, 1991, 1992; Hessle, 1917; Hilbig & Blake, 2006; Holthe, 1986; Kinberg, 1866, ; Knox, 1962; Levenstein, 1964; Licher, 1999; Monro, 1930, 1936, 1939; McIntosh, 1879, 1885; Perrson & Pleijel, 2005; Pocklington & Fournier, 1987; Ramsay, 1914; San Martín & Parapar, 1997; Uschakov, 1952; Wesenberg-Lund, 1949, 1961; Willey, 1902, unpublished data).

42 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 33 3 Results 3.1 Composition of polychaete communities During the expeditions a total of 14,176 specimens were collected belonging to 47 families specimens from 38 families originated from the expeditions ANDEEP I- II and specimens from 46 families from ANDEEP III. Eighty-two specimens could not be identified to family level due to poor condition. The complete assemblage matrices are given in App.-Tab App.-Fig. 2 summarizes the family composition of the different stations focusing on the most abundant families. Spionidae, Polynoidae, Opheliidae, Hesionidae, Ampharetidae, and Cirratulidae are among the dominant families at most stations. Spionidae, Polynoidae, Opheliidae, and Hesionidae are also among the most abundant families overall, together with the Syllidae, Pholoididae, Sphaerodoridae, and Terebellidae. The latter are only seldomly dominant at one station, they have a more even distribution over all stations. Only the families Ampharetidae, Glyceridae, Goniadidae, Hesionidae, Nephtyidae, Nereididae, Opheliidae, Sabellariidae, Scalibregmatidae, Sphaerodoridae, Syllidae, Terebellidae, and Trichobranchidae were determined to species level. These included 6669 specimens from 155 species (ANDEEP I-II: 1308 specimens/ 89 species, ANDEEP III: 5361 specimens/ 130 species). App.-Tab. 4-6 give a detailed overview of the species composition at each station. Among the 155 discriminated species a total of 46 species are new to science, 17 species could not be determined to species level without doubt (labeled as aff. or cf.). Twenty species could only be determined to higher taxonomic levels due to low abundance and poor condition. It is, therefore, unclear whether these specimens are already named species or new to science. In course of this study 18 new species were described, three of these descriptions are already published (Schüller & Hilbig, 2007); the remaining 15 descriptions are presented in the following chapters. Additionally, species identification keys are presented considering only the species found and determined in this study.

43 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION Identification keys to selected species found during ANDEEP I-III Key to the Ampharetidae MALMGREN 1866 A total of 464 Ampharetidae have been collected belonging to 34 species. One specimen was a juvenile of the genus Amphicteis and could not be determined to any species. Ten species (Ampharetidae ssp. 1 8, Eusamythella sp. 1, and Samytha sp. 1) were only present with few individuals of poor condition, a determination of these species was not possible. The determination of three further species, respectively genera, is in question. Eight species new to science were collected. 1 Anterior chaetigers with needle-like uncini. Segment four with nuchal hooks. Segment six with a pectinate postbranchial membrane (App.-Fig. 3A)...Melinna only M. cristata # Uncini never needle-like. Nuchal hooks and postbranchial membrane absent Four pairs of branchiae..3 # Three pairs of branchiae Palae present (App.-Fig. 3B).4 # Palae absent 7 4 Twelve thoracic uncinigers 5 # Fourteen thoracic uncinigers.amphicteis Palae short, few. Abdominal segments number 10. Pygidium with 2 dorsal cirri A. gunneri Palae fine, of median length. 10 abdominal segments. Last thoracic segment dorsally with 2 wing-like appendages (App.-Fig. 3C) A. sp. 1 With eyes. Prostomium anteriorly tapering, projecting upwards. Dorsal ridge on segment 3. Wing-like appendages on last thoracic segment. Palae fine, of median length.a. sp. 2 Prostomium with 2 button-shaped anterior projections. Palae long and coarse. Abdominal notopodial rudiments button-shaped to spherical, posterior segments inflated.a. sp. 3

44 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 35 5 Fourth or fifth to last thoracic chaetiger with elevated parapodia or dorsal ridge. Uncini from third or fourth thoracic chaetiger..6 # Dorsal ridge absent. Parapodia not elevated. Uncini from third thoracic chaetiger. Abdomen without notopodial rudiments..ampharete only A. kerguelensis 6 Fifth-to-last parapodia elevated (App.-Fig. 3D) with hirsute chaetae. Branchiae and buccal tentacles papillose Anobothrella Palae slender, arranged in a whirl A. antarctica Palae slender, arranged in a straight line.a. sp. 1 # Fourth or fifth to last thoracic chaetiger with dorsal ridge. Branchiae and buccal tentacles smooth...anobothrus Palae long and slender. Uncini from fourth segment after palae...a. gracilis Palae stout. Suddenly tapering to a fine tip. Uncini from third segment after palae (Fig. 4A)..A. pseudoampharete sp.n. 7 Twelve thoracic uncinigers 8 # Fourteen thoracic uncinigers...amphisamytha # Eleven thoracic uncinigers...amage only A. sculpta 8 Parapodia not elevated...9 # Third to last thoracic parapodia elevated (App.-Fig. 3D)..Sosanopsis Prostomium distinctly scoop shaped, trilobed (App.-Fig. 3E-F), branchiae all of similar width...s. kerguelensis Prostomium not scoop shaped. Median branchiae distinctly broader than lateral ones..s. sp. 1 9 Branchial position nearly segmental. Branchiae and buccal tentacles smooth.grubianella Prostomium anterior with two spherical processes. Posterior end inflated with two long cirri.g. antarctica Prostomium anteriorly slightly incised. 12 abdominal segments. Posterior end not inflated G. sp. 1

45 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 36 # Branchial position one in front of the other three. Branchiae lamellate Phyllocomus only P. crocea 10 With palae (App.-Fig. 3B) # Without palae Twelve thoracic uncinigers..12 # Nine thoracic uncinigers. Last notopodia elevated, chaetae crossing over dorsum (App.-Fig. 3G)..Mugga only M. sp. 1BH 12 Uncini from third thoracic chaetiger. Abdomen without notopodial rudiments...neosabellides only N. elongatus # Uncini from fourth thoracic chaetiger. Abdomen with notopodial rudiments...eusamythella 13 More than ten thoracic uncinigers...14 # Ten thoracic uncinigers.muggoides Last notopodia slightly elevated..m. cinctus Last notopodia not elevated...m. sp. 1BH 14 Fourteen thoracic uncinigers 15 # Eleven thoracic uncinigers. Prostomium scoop-shaped. Abdomen without notopodial rudiments..glyphanostomum only G. scotiarum 15 Uncini from fourth thoracic chaetiger...samytha # Uncini from third thoracic chaetiger. Buccal tentacles short, on thick membrane. Outermost branchiae grooved...amythas only A. membranifera

46 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 37 Annotated species list Amage sculpta EHLERS 1908 Stations (No of specimens): 42-2 (1), 21-7 (8), 74-6 (1), 80-9 (3), (1), (2) Distribution: subantarctic, m Records: Benham, 1927; Ehlers, 1908; Hartman, 1966; 1967; 1978; Hartmann-Schröder & Rosenfeldt, 1989; 1991; Monro, 1930; 1936 Ampharete kerguelensis MCINTOSH 1885 Stations (No of specimens): 41-3 (2), 46-7 (7), (13), 59-5 (1), 78-9 (7), 81-8 (6), (1) Distribution: subantarctic and Southern Atlantic, m Records: Augener, 1932; Ehlers, 1913; Hartman, 1966; 1967; 1978; Hartmann-Schröder & Rosenfeldt, 1989; 1991; Hessle, 1917; McIntosh, 1885; Monro, 1936; 1939 Ampharetidae sp. 1 Stations (No of specimens): (1) Ampharetidae sp. 2 Stations (No of specimens): (2), 21-7 (1), 78-9 (2), (2), (1), (5) Ampharetidae sp. 3 Stations (No of specimens): (2) Ampharetidae sp. 4 Stations (No of specimens): (1) Ampharetidae sp. 5 Stations (No of specimens): 78-9 (2)

47 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 38 Ampharetidae sp. 6 Stations (No of specimens): 80-9 (1), 81-1 (1) Ampharetidae sp. 7 Stations (No of specimens): 81-8 (2) Ampharetidae sp. 8 Stations (No of specimens): Amphicteis gunneri (SARS 1835) Stations (No of specimens): 46-7 (1), 78-9 (1), 80-9 (1), (1) Distribution: cosmopolitan, m Records: Augener, 1932; Hartley, 1985; Hartman, 1952; 1953; 1966; Hartmann- Schröder, 1996; Hartmann-Schröder & Rosenfeldt, 1989; 1991; Hessle, 1917; Holthe, 1986; Monro, 1930; 1936; 1939 Amphicteis juvenile Stations (No of specimens): 78-9 (1) Amphicteis sp. 1 Stations (No of specimens): 41-3 (1), 78-9 (15), 81-8 (1), (32), (1), (8), (3) Amphicteis sp. 2 Stations (No of specimens): 78-9 (7) Amphicteis sp. 3 Stations (No of specimens): 74-6 (5), 80-9 (1), (1), (2), (1) cf. Amphisamytha Stations (No of specimens): 74-6 (1)

48 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 39 Amythas membranifera BENHAM 1921 Stations (No of specimens): (1), (3) Distribution: subantarctic, m Records: Benham, 1921; Hartman, 1966; Monro, 1939 Anobothrella antarctica (MONRO 1939) Stations (No of specimens): (1), 74-6 (3), 81-8 (1), (1) Distribution: subantarctic, m Records: Hartman, 1967; 1978; Hartmann-Schröder & Rosenfeldt, 1989; 1991; Monro, 1939 Anobothrella sp. 1 Stations (No of specimens): 81-8 (1) Anobothrus gracilis (MALMGREN 1866) Stations (No of specimens): 81-8 (2), (1), (7), (2) Distribution: cosmopolitan, shelf down to 4817 m Records: Hartmann-Schröder, 1996; Hessle, 1917; Hilbig & Blake, 2006 Anobothrus pseudoampharete sp.n. Stations (No of specimens): 42-2 (1), (1), (7), 21-7 (1), 74-6 (104), 81-8 (3), (9), 13-2 (4), (1), (12), (1) cf. Eusamythella Stations (No of specimens): 42-2 (4), 74-6 (1), 81-8 (2) Glyphanostomum scotiarum HARTMAN 1978 Stations (No of specimens): 42-2 (3), (1), 74-6 (3), 78-9 (1) Distribution: Drake Passage to Weddell Sea, m Records: Hartman, 1978

49 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 40 Grubianella antarctica MCINTOSH 1885 Stations (No of specimens): 42-2 (2), (2), (1) Distribution: subantarctic to Southern Atlantic, m Grubianella sp. 1 Stations (No of specimens): 74-6 (1) Melinna cristata (SARS 1851) Stations (No of specimens): 80-9 (4), (4) Distribution: cosmopolitan, m Records: Ehlers, 1908; Hartman, 1966; 1967; Hartmann-Schröder, 1996; Hartmann- Schröder & Rosenfeldt, 1989; Hessle, 1917; Holthe, 1986; Monro, 1930 Mugga sp. 1BH Stations (No of specimens): (1), (3), (1) Muggoides cf. cinctus HARTMAN 1965 Stations (No of specimens): 81-8 (11) Distribution: cosmopolitan, down to 4419 m Records: Ebbe (pers. comment) Muggoides sp. 1BH Stations (No of specimens): 42-2 (1), (2), (4) Neosabellides elongatus (EHLERS 1912) Stations (No of specimens): 46-7 (2), (1), 21-7 (1), 74-6 (4), 78-9 (2), 80-9 (1), 81-8 (1), (1), (2) Distribution: subantarctic, m Records: Benham, 1927; Ehlers, 1912; 1913; Hartman, 1953; 1966; 1967; 1978; Hartmann-Schröder & Rosenfeldt, 1989; 1991; Monro, 1930; 1936; 1939

50 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 41 cf. Neosabellides Stations (No of specimens): 74-6 (1) Phyllocomus crocea GRUBE 1877 Stations (No of specimens): 59-5 (2), 74-6 (2), 81-8 (2), (2) Distribution: subantarctic, m Records: Augener, 1932; Benham, 1921; Grube, 1877; Hartman, 1966; 1967; Hartmann-Schröder & Rosenfeldt, 1989; Hessle, 1917; Monro, 1930; 1936; 1939 Samytha sp. 1 Stations (No of specimens): 74-6 (1) Sosanopsis kerguelensis MONRO 1939 Stations (No of specimens): (3), (2), (4), 21-7 (6), 59-5 (4), 74-6 (3), 78-9 (1), 80-9 (2), 88-8 (1), (3), (1), (2), (3), (8), (2), (6), (1) Distribution: subantarctic and Soutern Atlantic Records: Hartman, 1966; 1978, Monro, 1939, m Sosanopsis sp. 1 Stations (No of specimens): (5), (2) Glyceridae GRUBE 1850 The Glyceridae are represented in the samples by 353 specimens that all belong to one species. Glycera kerguelensis MCINTOSH 1885 Stations (No of specimens): 41-3 (1), 42-2 (2), 46-7 (3), (17), (23), (31), (4), 21-7 (2), 59-5 (14), 74-6 (43), 78-9 (47), 80-9 (45),

51 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION (2), (19), (8), (29), (19), (6), (4), (5) Distribution: subantarctic and Southern Atlantic, m Records: Hartman, 1964; 1967; 1978; Hartmann-Schröder & Rosenfeldt, 1988; 1990; 1992; McIntosh, Key to the Goniadidae KINBERG 1866 Six goniadid specimens from three species have been collected, two of them are new to science. 1 Proboscis lateral with chevrons (App.-Fig. 3H). Neurochaetae only spinigers...goniada only G. maculata # Proboscis without chevrons. Neurochaetae variable Bathyglycinde Prechaetal lobes bilobate...bathyglycinde sp. 1BH Prechaetal lobes simple Bathyglycinde sp. 2 Annotated species list Bathyglycinde sp. 1BH Stations (No of specimens): 42-2 (3), (1) Bathyglycinde sp. 2 Stations (No of specimens): 42-2 (1) Goniada maculata ÖRSTEDT 1843 Stations (No of specimens): (1) Distribution: cosmopolitan, m Records: Hartman, 1950; Hilbig & Blake, 2006

52 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION Key to the Hesionidae GRUBE 1850 Ten species of at least six genera are found for the Hesionidae (1420 specimens). Fourteen specimens from two species could not be identified (Hesionidae sp. 1, aff. Hesionides). Five species are new to science, four of them are described in this study. 1 Four pairs of tentacular cirri, three antennae.hesionides # Six or eight pairs of tentacular cirri Six pairs of tentacular cirri.3 # Eight pairs of tentacular cirri.5 3 Two antennae. Parapodia uniramous.4 # Three antennae. Parapodia biramous. Eversible pharynx distally with numerous fine cirri.ophiodromus Dorsal cirri long, articulated. Two pairs of eyes.o. comatus Dorsal and ventral cirri smooth. Eyes absent. Posterior margin of prostomium light brown in ethanol (Fig. 5E-H) O. calligocervix sp.n. 4 Eversible pharynx distally with numerous fine cirri (Fig. 6D)...Parasyllidea only P. delicata sp.n. # Eversible pharynx with eleven distal papillae (Fig. 6A)......Micropodarke M. cylindripalpata sp.n. 5 Three antennae. Parapodia biramous.6 # Two antennae. Parapodia uniramous. Eversible pharynx distally with numerous fine cirri Kefersteinia only K. fauveli 6 Median antenna attached medially (Fig. 5A). Pharynx terminally with ring of numerous cirri..amphiduros Notochaetae chambered and serrated (Fig. 5C).A. serratus sp.n.

53 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 44 Notochaetae not serrated.a. sp. 1 # Median antenna attached frontally (App.-Fig. 3J). Eversible pharynx with 40 distal papillae.gyptis only G. incompta Annotated species list Amphiduros serratus sp.n. Stations (No of specimens): (2), (1), (2) Amphiduros sp. 1 Stations (No of specimens): 46-7 (12), (1), (1) Gyptis incompta EHLERS 1912 Stations (No of specimens): 74-6 (48), (736) Distribution: subantarctic and Southern Pacific, m Records: Ehlers, 1912; 1913; Wesenberg-Lund, 1961 Hesionidae sp. 1 Stations (No of specimens): (3) aff. Hesionides Stations (No of specimens): (4), 21-7 (3), 59-5 (1), 88-8 (1), (2) Kefersteinia fauveli AVERNICEV 1972 Stations (No of specimens): (35), (3), 59-5 (6), 74-6 (70), (203), (11) Distribution: South Atlantic and Atlantic sector of the Southern Ocean, m Records: Hartman, 1978; Hartmann-Schröder & Rosenfeldt 1988; 1990; 1992

54 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 45 Micropodarke cylindripalpata sp.n. Stations (No of specimens): 42-2 (9), 46-7 (4), (2), (2), (1), 21-7 (2), 59-5 (5), 80-9 (5), 81-8 (4), 88-8 (6), (1), (2), (1), (3), (2) Ophiodromus calligocervix sp.n. Stations (No of specimens): 42-2 (28), (3), (1), (6), (1), (1), (1), (2), 21-7 (3), 59-5 (2), 78-9 (14), 80-9 (12), 88-8 (8), (4), (1), (3), (1), (7), (2) Ophiodromus comatus (EHLERS 1912) Stations (No of specimens): 74-6 (25), 80-9 (7), 81-8 (3), (4), (43), (3), (17), (1) Distribution: subantarctic, m Records: Ehlers, 1912; 1913; Hartman, 1964 Parasyllidea delicata sp.n. Stations (No of specimens): (1), (2), 21-7 (3), 80-9 (4), (2), (3), (7), 53-7 (1) Key to the Nephtyidae GRUBE 1850 A total of 177 specimens from three species (two genera) were found for the Nephtyidae. The species of the genus Aglaophamus are named, that of the genus Micronephtys is new to science. 1 Interramal cirri strongly reduced or absent...micronephtys only M. sp. 1 # Interramal cirri involute (App.-Fig. 3I).....Aglaophamus Postchaetal lobes always shorter than parapodial lobes, broadly rounded.a. paramalmgreni Postchaetal lobes large, longer than wide A. trissophyllus

55 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 46 Annotated species list Aglaophamus paramalmgreni HARTMANN-SCHRÖDER & ROSENFELDT 1992 Stations (No of specimens): 42-2 (5), 46-7 (6), 59-5 (14), 78-9 (1), (2), (1), (2), (1), (15) Distribution: Weddell Sea, Antarctic Peninsula, m Records: Hartmann-Schröder & Rosenfeldt, 1992 Aglaophamus trissophyllus (GRUBE 1866) Stations (No of specimens): 42-2 (2), 46-7 (27), 74-6 (73), 78-9 (18), 80-9 (2), (1), (2), (4) Distribution: Weddell Sea, Antarctic Peninsula, m Records: Hartman, 1978 Micronephtys sp. 1 Stations (No of specimens): 46-7 (1) Key to the Nereididae JOHNSTON 1865 The Nereididae are represented by ten specimens from three different species and genera. Only one species is identified without doubt, one species might be new to science. 1 Eversible pharynx without paragnaths and papillae..nicon # Eversible pharnyx with pharyngeal processes Eversible pharynx with soft papillae. Ventral cirri partially double.. Ceratocephale only C. sp. 1BH

56 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 47 # Eversible pharynx with conical paragnaths. Ventral cirri simple throughout. Falcigers and spinigers in posterior notopodia.nereis only N. eugeniae Annotated species list Ceratocephale sp. 1BH Stations (No of specimens): 78-9 (1), 88-8 (1), (1), (1), (1) Nereis eugeniae (KINBERG 1866) Stations (No of specimens): 42-2 (1), 46-7 (1), (1) Distribution: Southern hemisphere, m Records: Ehlers, 1897; 1900; 1901; Fauvel, 1941; Hartman, 1964; Hartmann-Schröder & Rosenfeldt, 1992; Kinberg, 1866; Monro, 1930; 1936; 1939; Ramsay, 1914; Wesenberg-Lund, 1961 cf. Nicon KINBERG 1866 Stations (No of specimens): (1) Key to the Opheliidae MALMGREN 1867 A total of 479 specimens from two genera and 14 species of Opheliidae were found. Six of these species were already known to science, the remaining eight are new. In this study, two species of the genus Ophelina are described, as well as three species of Ammotrypanella. In addition, the genus Ammotrypanella is redefined and the type species redescribed. 1 Body elongated with a ventral groove along whole body length. Branchiae present on anterior and posterior segments..ophelina

57 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 48 Without branchiae on last four chaetigers. These distinctly reduced in length (App.-Fig. 3L)..O. breviata Without anal tube. Without branchiae on last three to four chaetigers. These not distinctly reduced (App.-Fig. 3K)..O. gymnopyge Without branchiae and distinct segmental sutures. Reminiscent of Nematoda.O. nematoides Without branchiae at posterior segments. These ventrally concave with a pair of cirriform processes..o. scaphigera Anterior chaetigers numerous, prolonged, and bent. Analtube marginally with circlet of fine cirri...o. setigera Branchiae enlarged in third charter of body and missing in last. Anal tube without ventral cirrus, margin with numerous fine cirri (Fig. 8F)..O. ammotrypanella sp.n. Anterior branchiae of median size, posterior ones enlarged. Anal tube seemingly articulated, with robust ventral cirrus and marginally with fine cirri (Fig. 8D) O. robusta sp.n. Anterior branchiae prolonged. Without branchiae on last three chaetigers. These not reduced in length. Anal tube with ventral cirrus...o. sp. 3 Branchiae only present from chaetiger Segmental sutures very indistinct O. sp. 4 Anterior branchiae of median size. Anal tube strongly reduced in length, without ventral cirrus O. sp. 5 # Body elongated with a ventral groove along whole body length. Branchiae limited to posterior half of the body (Figs. 7)..Ammotrypanella Anal tube without ventral cirrus, margin with short cirri (Fig. 7E) A. arctica Anal tube with thick ventral cirrus, margin with short cirri (Fig. 7B).A. cirrosa sp.n. Anal tube with ventral cirrus, margin smooth (Fig. 7F)..A. princessa sp.n. Without anal tube (Fig. 8B).A. mcintoshi sp.n. Annotated species list Ammotrypanella arctica MCINTOSH 1879 Stations (No of specimens): 42-2 (2), (7), (1), (6), 59-5 (4), 78-9 (1), (2), (14), (22), (2), (3) Distribution: cosmopolitan, m Records: Ebbe (pers. comment); Hartman & Fauchald, 1971; McIntosh, 1879

58 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 49 Ammotrypanella cirrosa sp.n. Stations (No of specimens): 42-2 (4), (64), (2), (1), (6), 59-5 (2), 78-9 (2), (4), (1), (40), (4), (1) Ammotrypanella princessa sp.n. Stations (No of specimens): 42-2 (1), (1), (1), (1), 78-9 (1), 81-8 (1), (1), (1) Ammotrypanella mcintoshi sp.n. Stations (No of specimens): (3), 21-7 (1), 59-5 (1), 74-6 (2), (3), (1) Ophelina breviata (EHLERS 1913) Stations (No of specimens): 42-2 (1), 46-7 (2), (16), (1), 74-6 (16), 78-9 (1), (1), (1), (6), (19), (1), (1), (1) Distribution: subantarctic and Southern Atlantic, m Records: Augener, 1932; Hartman, 1953; 1966; 1978; Hartmann-Schröder & Rosenfeldt, 1989; 1991; Monro, 1930; 1936; 1939 Ophelina gymnopyge (EHLERS 1908) Stations (No of specimens): 42-2 (3), (15), (2), 59-5 (1), 81-8 (3), (3), (2), (14), (4) Distribution: South Atlantic and Atlantic sector of the Southern Ocean, m Records: Ehlers, 1908; Hartman, 1952; 1953; 1966; Hartmann-Schröder & Rosenfeldt, 1989; 1991 Ophelina nematoides (EHLERS 1913) Stations (No of specimens): 41-3 (1), 42-2 (14), 46-7 (7), (2), (5), (2), 74-6 (18), 80-9 (1), (1) Distribution: subantarctic and Southern Atlantic, m Records: Ehlers, 1913; Hartman, 1966; 1967; 1978; Hartmann-Schröder & Rosenfeldt, 1989; 1991

59 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 50 Ophelina scaphigera (EHLERS 1901) Stations (No of specimens): (4), 59-5 (1), (2) Distribution: South Atlantic and Atlantic sector of the Southern Ocean, m Records: Ehlers, 1900; 1901; Hartman, 1953; 1966; Monro, 1936 Ophelina setigera HARTMAN 1978 Stations (No of specimens): 46-7 (1), (1), (1) Distribution: South Atlantic and Atlantic sector of the Southern Ocean, m Records: Ebbe (pers. comment); Hartman, 1978 Ophelina ammotrypanella sp.n. Stations (No of specimens): (2), (4), 78-9 (10), 81-8 (4), (4), (7), (8) Ophelina robusta sp.n. Stations (No of specimens): (1), 78-9 (10), 80-9 (2), (4), (5), (2), (7) Ophelina sp. 3 Stations (No of specimens): (2) Ophelina sp. 4 Stations (No of specimens): 42-2 (1) Ophelina sp. 5 Stations (No of specimens): (10), (2), (5)

60 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION Sabellariidae JOHNSTON 1865 Only two specimens have been sampled for the Sabellariidae, belonging to one species. Phalacrostemma elegans FAUVEL 1911 Stations (No of specimens): 46-7 (1), 80-9 (1) Distribution: cosmopolitan, m Records: Gillet & Dauvin, 2000; Hartman, Key to the Scalibregmatidae MALMGREN 1867 The Scalibregmatidae are represented by 642 specimens from 19 species. Nine different genera were found. Six species were new to science, three of them have already been described in course of this study, an additional description is presented here. The identity of two species is not completely confirmed. 1 Body grub-, maggot- or barrel-shaped..2 # Body more elongated, sometimes anteriorly inflated, prostomium bifid or T- shaped (Fig. 9A, App.-Fig. 3M) 4 2 Prostomium entire, cone-shaped 3 # Prostomium with two lateral processes or incised...axiokebuita Notopodia with postchaetal lobes A. millsia Notopodia without postchaetal lobes..a. minuta 3 Branchiae absent Kesun only K. abyssorum # Branchiae present...travisia Segments number Pygidium with anal cylinder...t. kerguelensis Segements number 52 53, body prolonged. Pygidium with anal disc.t. lithophila

61 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 52 4 Posterior parapodia reduced...5 # Posterior parapodia not reduced 6 5 With acicular spines (App.-Fig. 3M)...Asclerocheilus only A. ashworthi # Without acicular spines.....hyboscolex only H. equatorialis 6 Posterior parapodia with dorsal and ventral cirri...7 # Posterior parapodia without dorsal cirri. Acicular spines present.sclerocheilus only S. antarcticus 7 Without branchiae..8 # With branchiae in anterior chaetigers.scalibregma only S. inflatum 8 Without acicular spines Pseudoscalibregma Rounded nuchal crest dorsally on prostomium. Broad dorsal and ventral cirri...p. bransfieldium Dorsal and ventral cirri enlarged, foliose to wing-like in posterior segments (Fig. 9C).P. papilia sp.n. Dorsal and ventral cirri drop-shaped, with bacillary glands..p. ursapium # With acicular spines (App.-Fig. 3M).Oligobregma Chaetigers 1 and 2 with one row of acicular spines each.o. blakei Chaetigers 1 and 2 with two rows, chaetiger 3 with one row of acicular spines. Interramal sense organs present.o. collare Chaetigers 1 and 2 with inconspicious acicular spines. Dorsal surface papillated.o. hartmanae With Y-shaped eyes. One row of acicular spines in chaetigers 1 3.O. notiale Chaetigers 1 and 2 with two rows of acicular spines O. pseudocollare Chaetigers 1 and 2 with two rows, chaetigers 3 and 4 with one row of acicular spines..o. quadrispinosa Acicular spines as O. collare. No interramal sense organs present O. sp. 1

62 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 53 Annotated species list Asclerocheilus ashworthi BLAKE 1981 Station (No of specimens): 46-7 (1) Distribution: subantarctic, m Records: Blake, 1981 Axiokebuita millsi POCKLINGTON & FOURNIER 1987 Stations (No of specimens): (62) Distribution: cosmopolitan, m Records: Pocklington & Fournier, 1987 Axiokebuita minuta (HARTMAN 1967) Stations (No of specimens): 46-7 (1), (6), (1), (3), (11), 74-6 (8), 80-9 (7), 81-8 (1), (15), (2) Distribution: cosmopolitan, m Records: Blake, 1981; Hartman, 1967; 1978; Persson & Pleijel, 2005 Hyboscolex equatorialis BLAKE 1981 Stations (No of specimens): (1) Distribution: South Sandwich Trench, west coast of South America, m Records: Blake, 1981 Kesun abyssorum MONRO 1930 Stations (No of specimens): 46-7 (86), (1), (3), (8), 21-7 (1), 59-5 (14), 78-9 (24), 80-9 (8), 81-8 (1), (1), (3), (4), (14), (2), (4), (26), (54), (11) Distribution: South Atlantic and Atlantic sector of the Southern Ocean, m Records: Augener, 1932; Hartman, 1966; 1978; Monro, 1930; 1939

63 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 54 Oligobregma blakei SCHÜLLER & HILBIG 2007 Stations (No of specimens): 46-7 (1), (1), (2) Distribution: Weddell and Scotia Sea, m Records: Schüller & Hilbig, 2007 Oligobregma collare (LEVENSTEIN 1978) Stations (No of specimens): 42-2 (4), 46-7 (3), (8), (2), 59-5 (1), 74-6 (1), 78-9 (7), 80-9 (1), (1), (11), (3), (1), (1), (1), (10), (1) Distribution: subantarctic, m Records: Hartman, 1967; 1978; Blake, 1981 Oligobregma hartmanae BLAKE 1981 Stations (No of specimens): 59-5 (3), (2); (1) Distribution: Antarctic sector of the Southern Ocean, m Records: Blake, 1981 Oligobregma notiale BLAKE 1981 Stations (No of specimens): 42-2 (7) Distribution: subantarctic, m Records: Blake, 1981 Oligobregma pseudocollare SCHÜLLER & HILBIG 2007 Stations ( no specimens): 46-7 (20), (1), (8), 80-9 (2), (1), (8), (1), (2) Distribution: Weddell and Scotia Sea, m Records: Schüller & Hilbig, 2007

64 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 55 Oligobregma quadrispinosa SCHÜLLER & HILBIG 2007 Stations (No of specimens): 42-2 (5), (8), (2), (1), 21-7 (1), 59-5 (6), 88-8 (1), (2), (1), (1), (1), (1), (10) Distribution: Weddell and Scotia Sea, m Records: Schüller & Hilbig, 2007 Oligobregma sp. 1 Stations (No of specimens): (1) Pseudoscalibregma bransfieldium (HARTMAN 1967) Stations (No of specimens): 42-2 (8), 46-7 (5), (6), (2), 74-6 (2), 80-9 (1), 88-8 (1), (2), (1), (1), (1) Distribution: subantarctic, m Records: Blake, 1981; Hartman, 1967; 1978 Pseudoscalibregma papilia n. sp. Stations (No of specimens): 42-2 (3), 46-7 (2), (3), (1), (1), (5), (1) Pseudoscalibregma ursapium BLAKE 1981 Stations (No of specimens): 42-2 (1), 46-7 (1), (1), 80-9 (3), (5), (1) Distribution: subantarctic, m Records: Blake, 1981 Scalibregma inflatum RATHKE 1843 Stations (No of specimens): 42-2 (3), 46-7 (2), (1), (2) Distribution: cosmopolitan, m Records: Blake, 1981; Ebbe (pers. comment), Ehlers, 1900; 1901; Fauchald, 1972; Fauvel, 1941; Hartman, 1967; 1978; Hartmann-Schröder, 1965; 1996; Hartmann-Schröder & Rosenfeldt, 1989; 1991; Hilbig & Blake, 2006; Monro, 1930

65 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 56 Sclerocheilus cf. antarcticus ASHWORTH 1915 Stations (No of specimens): 80-9 (1) Distribution: Antarcic Peninsula and Weddell Sea, m Records: Blake, 1981 Travisia kerguelensis MCINTOSH 1885 Stations (No of specimens): 46-7 (1), (6), 59-5 (1), 74-6 (6), 78-9 (4), (2), (3), (1), (9) Distribution: subantarctic, m Records: Augener, 1932; Ehlers, 1897; 1900; 1901; 1912; Fauvel, 1941; Hartman, 1953; 1966; 1967; 1978; Hartmann-Schröder & Rosenfeldt, 1989; 1991; Knox, 1962; McIntosh, 1885; Monro, 1930; 1936; 1939; Willey, 1902 Travisia cf. lithophila KINBERG 1866 Stations (No of specimens): (1) Distribution: subantarctic and Southern Pacific, m Records: Hartman, 1952; 1966; Kinberg, 1866; Key to the Sphaerodoridae MALMGREN 1867 Three genera of Sphaerodoridae have been found, contributing 891 specimens from eight species. Four of the species are known to science, the other four are new and described in this study. 1 Macrotubercles seated on dorsum (Fig. 10)...2 # Macrotubercles on a short stem (App.-Fig. 3N)..Clavodorum only C. antarcticum 2 Macrotubercles in two rows...ephesiella Body long. More than 50 segments. First chaetiger with recurved hooks.e. antarctica

66 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 57 Body shorter, less than 50 segments. Recurved hooks not apparent (Fig. 10A)...E. hartmanae sp.n. # Macrotubercles in at least four rows Sphaerodoropsis Two pairs of lateral antennae. Tentacular cirri and antennae long. Macrotubercles large and distinctly spherical (Fig. 10E) S. distincta sp.n. Three pairs of lateral antennae. Macrotubercles cone-shaped. Surface speckled with purple to black pigments (Fig. 10H) S. maculata sp.n. Three pairs of lateral antennae. Macrotubercles well developed...s. parva With 7 9 rows of macrotubercles.s. polypapillata Two pairs of lateral antennae. Macrotubercles somewhat rectangular, little pronounced (Fig. 10K).S. simplex sp.n. Annotated species list Clavodorum antarcticum HARTMANN-SCHRÖDER & ROSENFELDT 1990 Stations (No of specimens): 46-7 (1), (1), (1) Distribution: Antarctic Peninsula and Weddell Sea, m Records: Hartmann-Schröder & Rosenfeldt, 1990; 1992 Ephesiella antarctica (MCINTOSH 1885) Stations (No of specimens): 42-2 (1), 46-7 (5), (8), (1), (2) Distribution: subantarctic, m Records: Ehlers, 1912; 1913; Hartman,1964; 1978; Hartmann-Schröder & Rosenfeldt, 1992; McIntosh, 1885; Monro, 1930; 1936; 1939 Ephesiella hartmanae sp.n. Stations (No of specimens): (3), (1), 74-6 (2), 80-9 (1), (3), (1) Sphaerodoropsis distincta sp.n. Stations (No of specimens): 46-7 (6)

67 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 58 Sphaerodoropsis maculata sp.n. Stations (No of specimens): 74-6 (23) Sphaerodoropsis parva (EHLERS 1913) Stations (No of specimens): 41-3 (2), 42-2 (82), 46-7 (333), (21), (11), (1), 21-7 (1), 59-5 (6), 74-6 (87), 78-9 (3), 80-9 (6), 81-8 (28), (189), (2), (11), (1), (3), (2) Distribution: Southern hemisphere, m Records: Ehlers, 1913; Hartman, 1953; 1964; 1967; 1978; Hartmann-Schröder, 1965; Hartmann-Schröder & Rosenfeldt, 1988; 1990; 1992; Wesenberg-Lund, 1961 Sphaerodoropsis polypapillata HARTMANN-SCHRÖDER & ROSENFELDT 1988 Stations (No of specimens): 42-2 (1), (2), 80-9 (4), (5), (2) Distribution: South Atlantic and Atlantic sector of the Southern Ocean, m Records: Hartmann-Schröder & Rosenfeldt, 1988; 1992 Sphaerodoropsis simplex sp.n. Stations (No of specimens): 46-7 (22), (1), 74-6 (3), 80-9 (1), (1) Key to the Syllidae GRUBE 1850 The Syllidae are represented by 1331 specimens. In total twenty-one species from eight genera have been found. The identification of four species is not without doubt, one of them is a stolon probably of Autolytus simplex EHLERS 1900 (station 46-7). Six species are new to science. 1 Without ventral cirri...2 # With ventral cirri 3

68 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 59 2 Two pairs of tentacular cirri, three antennae. Each chaetiger with a ciliary band. Simple chaetae delicate, thinner than composite ones.autolytus only A. gibber # Two pairs of tentacular cirri, three antennae. Chaetiger without ciliary bands. Simple chaetae as robust as composite ones...proceraea only P. mclearanus 3 Tentacular cirri and dorsal cirri more or less smooth 4 # Tentacular and dorsal cirri distinctly articulated.typosyllis Delicate species. Chaetal appendages bifid. Dorsal cirri alternate long (12 15 articles) and short (8 10 articles)...t. hyalina Chaetae composite, unidentate falcigers. Long dorsal cirri with about 50 articles T. variegata 4 One pair of tentacular cirri.5 # Two pairs of tentacular cirri Body epidermis covered with numerous fine papillae. Dorsal cirri flask shaped (App.-Fig. 4A)...Sphaerosyllis Sparsely papillated. Chaetiger 2 without dorsal cirri. Eyes black. Proventriculus in 4 5 segments (18 20 cell rows) S. antarctica Sparsely papillated. Chaetiger 2 with dorsal cirri. Eyes red. Proventriculus in 5.5 segments (25 28 cell rows)...s. joinvillensis Strongly papillated. Chaetiger 2 without dorsal cirri. Proventriculus in about 3 segments (13 17 cell rows)..s. lateropapillata uteae # Epidermis without numerous papillae. Dorsal cirri variable in size and shape Dorsal cirri long, slender. Eversible pharynx unarmed Braniella only B. palpata # Dorsal cirri short, papilliform. Eversible pharynx with a single tooth..exogone Proventriculus in segments (13 16 cell rows). Modified chaetae with triangular blades. Two pairs of eyes. Lateral and median antennae similar.e. heterosetosa

69 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 60 Proventriculus in 3 segments. Long and short falcigers present with serrated blades (composite, plus some simple in median body region). Median antenna prolonged..e. minuscula Proventriculus in 1.5 segments (12 cell rows). Chaetal blades serrated, bidentate.e. sp. 2BH Proventriculus in 2 3 segments (~ 14 cell rows). Two pairs of eyes close to each other. Three antennae similar in shape, in a narrow row between the eyes.e. sp. 5 Proventriculus in segments (~ 17 cell rows). Median antenna spindle-shaped, longer than lateral ones E. sp. 6 No eyes. Lateral antennae distinctly lateral in position. Proventriculus in about six segments.e. sp. 7 7 Small forms of few millimeters. Palps fused at least partially. Dorsal cirri long..brania only B. sp.1bh # Larger forms. Palps maximally fused at base 8 8 Pharynx unarmed Syllides only S. articulosus # Pharynx with a single tooth. Dorsal cirri cylindrical.pionosyllis Prostomium posteriorly notched. Notch covered by first subsequent segment. Two pairs of eyes (App.Fig. 4B).P. comosa Prostomium with deep longitudinal groove and posterior incision. These not covered. Two pairs of eyes (App.-Fig. 4C) P. epipharynx Prostomium neither notched nor incised. Two pairs of eyes P. maxima Prostomium with deep longitudinal groove and posterior incision. Eyes absent.p. sp.1 Annotated species list Autolytus gibber EHLERS 1897 Stations (No of specimens): 74-6 (1) Distribution: subantarctic and Southern Pacific, m Records: Ehlers, 1897; 1901; Fauvel, 1936; 1951; Gravier, 1906; 1907; Hartman, 1954; 1964; Hartmann-Schröder & Rosenfeldt, 1992; Monro, 1930; 1936

70 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 61 Brania sp. 1BH Stations (No of specimens): (2), (1) Braniella palpata HARTMAN 1967 Stations (No of specimens): (2), 21-7 (1), 59-5 (1), 74-6 (3), 80-9 (2), 81-8 (1), (2), (32) Distribution: cosmopolitan, m Records: Ebbe (pers. comment); Hartman, 1967; 1978 Exogone heterosetosa MCINTOSH 1885 Stations (No of specimens): 42-2 (1), 74-6 (1) Distribution: cosmopolitan, m Records: Augener, 1912; Benham, 1921; 1927; Blankensteyn & Lana, 1986; Ehlers, 1897; 1901; 1913; Fauvel, 1916; 1936; Gravier, 1906; 1907; 1911; Hartman, 1953; 1964; Hartmann-Schröder, 1965; Hartmann-Schröder & Rosenfeldt, 1988; 1990; 1992; McIntosh, 1885; Monro, 1939; Wesenberg-Lund, 1961 Exogone minuscula HARTMAN 1953 Stations (No of specimens): 74-6 (8), (1), (18), (1) Distribution: Antarctic Peninsula and Weddell Sea, m Records: Blankenstey & Lana, 1986; Hartman, 1953; 1964; 1967; 1978 Exogone sp. 2BH Stations (No of specimens): 46-7 (1) Exogone sp. 5 Stations (No of specimens): 74-6 (5) Exogone sp. 6 Stations (No of specimens): (16)

71 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 62 Exogone sp. 7 Stations (No of specimens): (42) Pionosyllis comosa GRAVIER 1906 Stations (No of specimens): 74-6 (7) Distribution: subantarctic, m Records: Benham, 1921; 1927; Ehlers, 1912; 1913; Gravier, 1906; 1907; 1911; Harman, 1954; 1964; 1967; Monro, 1930 Pionosyllis epipharynx HARTMAN 1953 Stations (No of specimens): 46-7 (1), (1), (1), 74-6 (14), (24), (1), (1), (2) Distribution: Weddell Sea and Antarctic Peninsula, m Records: Hartman, 1964; 1967 Pionosyllis cf. maxima MONRO 1930 Stations (No of specimens): 74-6 (1) Distribution: Weddell Sea, m Records: Hartman, 1964; Hartmann-Schröder & Rosenfeldt, 1988; Monro, 1930 Pionosyllis sp. 1 Stations (No of specimens): (1) Proceraea cf. mclearanus (MCINTOSH 1885) Stations (No of specimens): 74-6 (1) Distribution: subantarctic and Southern Pacific, m Records: Benham, 1927; Ehlers, 1912; 1913; Hartman, 1964; Hartmann-Schröder & Rosenfeldt, 1990; 1992; McIntosh, 1885

72 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 63 Sphaerosyllis antarcticus GRAVIER 1907 Stations (No of specimens): 74-6 (1) Distribution: Weddell Sea, m Records: Hartmann-Schröder & Rosenfeldt, 1988; 1990; 1992 Sphaerosyllis joinvillensis HARTMANN-SCHRÖDER & ROSENFELDT 1988 Stations (No of specimens): (1), 74-6 (12), (285) Distribution: Weddell Sea, m Records: Hartmann-Schröder & Rsoenfeldt, 1988; 1992; San Martín & Parapar, 1996 Sphaerosyllis lateropapillata uteae HARTMANN-SCHRÖDER & ROSENFELDT 1988 Stations (No of specimens): (12), (1), 74-6 (156), (217), (5), (4), (38) Distribution: Weddell Sea, m Records: Hartmann-Schröder & Rosenfeldt, 1988; 1992 Syllides articulosus EHLERS 1897 Stations (No of specimens): 74-6 (1), (317) Distribution: subantarctic, m Records: Augener, 1932; Blankensteyn & Lana, 1986; Ehlers, 1879, 1901; 1912; 1913; Fauvel, 1916; Hartman, 1953; 1964; 1967; 1978; Hartmann-Schröder & Rosenfeldt, 1988; 1990; 1992; Monro, 1939 Typosyllis cf. hyalina (GRUBE 1863) Stations (No of specimens): (8), 74-6 (1), (5) Distribution: cosmopolitan, m Records: Ehlers, 1879; 1901; Fauvel, 1936; Gravier, 1911; Hartman, 1964; Hartmann- Schröder, 1996; Hartmann-Schröder & Rosenfeldt, 1992; Licher, 1999; Willey, 1902

73 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 64 Typosyllis variegata (GRUBE 1860) Stations ( no specimens): (4), (60) Distribution: cosmopolitan, m Records: Ehlers, 1900; 1901; Hartman, 1953; 1964; 1967; Hartmann-Schröder, 1996; Hartmann-Schröder & Rosendfeldt, 1992, Licher, 1999; Monro, 1930; Wesenberg-Lund, Key to the Terebellidae MALMGREN 1867 For the Terebellidae 683 specimens belonging to 32 species from at least 13 genera have been found. Due to a rather poor condition of most specimens the identity of seven species remains unclear. Four new species have been found. 1 Thoracic uncini in one row throughout..2 # Thoracic uncini at least partially in two rows 6 2 Branchiae present...3 # Branchiae absent 4 3 Three pairs of branchiae from segments 2 4. Notochaetae from first branchial segment (segment 2), uncini from 4 th chaetiger..streblosoma only S. variouncinatum # Three pairs of branchiae from segmenst 2 4. Notochaetae from second branchial segment (segment 3), uncini from 3 rd chaetiger Thelepus only T. cincinnatus 4 Chaetae present..5 # Chaetae absent. Ten thoracic segments.hauchiella only H. tribullata

74 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 65 5 Notochaetae from third segment, neurochaetae (uncini) absent...lysilla only L. sp. 1BH # Notochaetae from third segment, uncini from chaetigers 7 12 Polycirrus 11 thoracic chaetigers, 12 abdominal uncinigers P. antarcticus 11 thoracic setigers, 14 abdominal uncinigers. Notochaetae of one kind, slightly limbate, blade weakly denticulated...p. insignis Notochaetae of two kinds. Long slender ones smooth, shorter ones with serrated knob...p. sp. 1 Notochaetae of two kinds. Short ones limbate with broad wings...p. sp. 2 6 Branchiae present...7 # Branchiae absent 9 7 Two pairs of branchiae..8 # Three pairs of branchiae. Lateral lappets present. 17 thoracic segments Thelepides Branchial filaments in sessile bundles....t. koehleri Branchiae as single filaments...t. venustus 8 17 thoracic chaetigers. Branchiae smooth. Lateral lappets on segments 2 and 3. Some anterior uncini with prolonged shafts Eupistella Two pairs of branchiae on segments 2 and 3, both with single filaments (App.-Fig. 4D)...E. grubei Two pairs of branchiae on segments 2 and 3. Second pair with two filaments (App.-Fig. 4E).E. sp. 1 # Number of thoracic chaetigers varies from Branchiae stalked. Anterior thoracic uncini long-handed (App.-Fig. 4F) Pista Without lateral lappets on segment 2. Narrow lateral lappets on segment 4. Two pairs of branchiae on segments 2 and 3..P. corrientis With lateral lappets on segment 2. Two pairs of branchiae on segments 2 and 3.P. cristata Without lateral lappets on segment 2. Lappets on segment 1 greatly enlarged. One pair of branchiae on segment 2...P. spinifera

75 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 66 9 Lateral lappets present.10 # Lateral lappets absent Notochaetae distally smooth or dentate. Uncini from segment 3. Segments dorsally without ridges Proclea only P. graffii # Third segment dorsally with transverse ridge..leaena Thorax with chaetigers. Uncini in double rows through seventh abdominal segment.l. antarctica 16 thoracic chaetigers. Second segment dorsally short and laterally enlarged, projecting forward to form a ventral hood L. arenilega 17 thoracic chaetigers. Segment 3 with low dorsal ridge. Uncini in double rows through last thoracic segment L. collaris 15 thoracic chaetigers. Segments 2 and 3 with large lateral lappets and short digitiform processes that remind of branchiae. Uncini in double rows through first abdominal segment L. pseudobranchiata 15 thoracic chaetigers. First ventral segment with ventral collar. Segments 2 and 3 with lateral lappets. Uncini in double rows from chaetigers 7 15.L. wandelensis 17 chaetigers. Segment 4 with lateral lappets partially covering segment 3...L. sp thoracic segments. Notochaetae smooth, uncini from chaetiger 7.Laphania only L. boecki # 14 thoracic segments. Notochaetae distally denticulated, uncini from chaetiger 2 Phisidia 14 thoracic chaetigers...p. rubrolineata 16 thoracic chaetigers. Short chaetae with hirsute blades...p. sp. 1 Annotated species list Eupistella grubei (MCINTOSH 1885) Stations (No of specimens): 74-6 (9), 80-9 (3), (4) Distribution: subantarctic, m

76 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 67 Records: Hartman, 1966; 1978; Levenstein, 1964; McIntosh, 1885 Eupistella sp. 1 Stations (No of specimens): (2) Hauchiella tribullata (MCINTOSH 1869) Stations (No of specimens): 42-2 (1), 74-6 (2) Distribution: cosmopolitan, m Records: Hartman, 1966; 1978; Hartmann-Schröder, 1996; Hartmann-Schröder & Rosenfeldt, 1989; 1991; Hessle, 1917; Holthe, 1986; Monro, 1930; 1936 Laphania cf. boecki MALMGREN 1866 Stations (No of specimens): 46-7 (2) Distribution: cosmopolitan, m Records: Hessle, 1917 Leaena antarctica MCINTOSH 1885 Stations (No of specimens): 81-8 (1), (1), (2), (7) Distribution: subantarctic, m Records: Benham, 1927; Ehlers, 1897; 1900; 1901; 1913; Hartman, 1966; Hartmann- Schröder & Rosenfeldt, 1989; 1991; Hessle, 1917; Levenstein, 1964; McIntosh, 1885; Monro, 1930; 1936 Leaena arenilega EHLERS 1913 Stations (No of specimens): 74-6 (5), (1) Distribution: subantarctic, m Records: Benham, 1921; Ehlers, 1913; Hartman, 1966; 1978; Hartmann-Schröder & Rosenfeldt, 1991; Hessle, 1917 Leaena collaris HESSLE 1917 Stations (No of specimens): 74-6 (2), (64) Distribution: subantarctic and Southern Atlantic, m

77 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 68 Records: Hartman, 1966; Hartmann-Schröder & Rosenfeldt, 1989; 1991; Hessle, 1917; Monro, 1930; 1936 Leaena cf. collaris HESSLE 1917 Stations (No of specimens): (1), 74-6 (3) Leaena pseudobranchiata LEVENSTEIN 1964 Stations (No of specimens): 74-6 (3) Distribution: subantarctic, m Records: Hartman, 1966; Levenstein, 1964 Leaena wandelensis GRAVIER 1907 Stations (No of specimens): 21-7 (1) Distribution: subantarctic, m Records: Benham, 1927; Gravier, 1907; 1911; Hartman, 1952; 1966; Levenstein, 1964 Leaena sp. 4 Stations (No of specimens): 74-6 (1), (3) Lysilla sp. 1BH Stations (No of specimens): 46-7 (1) Phisidia rubrolineata HARTMANN-SCHRÖDER & ROSENFELDT 1989 Stations (No of specimens): (266) Distribution: Weddell Sea, m Records: Hartmann-Schröder & Rosenfeldt, 1989; 1991 Phisidia sp. 1BH Stations (No of specimens): (1) Pista corrientis MCINTOSH 1885 Stations (No of specimens): 74-6 (1)

78 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 69 Distribution: subantarctic and Southern Atlantic, m Records: Benham, 1927; Ehlers, 1913; Fauvel, 1951; Hartman, 1952; 1966; 1967; Hartmann-Schröder & Rosenfeldt, 1989; Hessle, 1917; Levenstein, 1964; McIntosh, 1885; Monro, 1930; 1939 Pista cristata (MÜLLER 1776) Stations (No of specimens): 74-6 (2) Distribution: cosmopolitan, m Records: Augener, 1932; Ehlers, 1900; 1901; Gravier, 1907; 1911; Hartman, 1966; 1967; Hartmann-Schröder, 1996; Hessle, 1917; Levenstein, 1964 Pista spinifera (EHLERS 1908) Stations (No of specimens): 74-6 (5) Distribution: subantarctic, m Records: Augener, 1932; Ehlers, 1908; 1913; Gravier, 1911; Hartman, 1966; 1967 Polycirrus cf. antarcticus (WILLEY 1902) Stations (No of specimens): 74-6 (1) Distribution: subantarctic, 1047 m Records: Hartman, 1966; Willey, 1902 Polycirrus insignis GRAVIER 1907 Stations (No of specimens): 46-7 (1), (1) 74-6 (13), 78-9 (3), (241), (2), (1), (1) Distribution: subantarctic, m Records: Fauvel, 1951; Gravier, 1907; Hartmann, 1966; Hartmann-Schröder & Rosenfeldt, 1989; Hessle, 1917 Polycirrus sp. 1 Stations (No of specimens): 59-5 (1)

79 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 70 Polycirrus sp. 2 Stations (No of specimens): 74-6 (1) Streblosoma variouncinatum HARTMANN-SCHRÖDER & ROSENFELDT 1991 Stations (No of specimens): (2) Distribution: Weddell Sea and Drake Passage, m Records: Hartmann-Schröder, 1991 Thelepides koehleri GRAVIER 1911 Stations (No of specimens): 74-6 (2) Distribution: Weddell Sea, m Records: Gravier, 1911; Hartman, 1966; 1967; 1978; Hartmann-Schröder & Rosenfeldt, 1989; 1991 Thelepides venustus LEVENSTEIN 1964 Stations (No of specimens): 74-6 (3) Distribution: subantarctic, m Records: Hartman, 1966; Levenstein, 1964 cf. Thelepides venustus LEVENSTEIN 1964 Stations (No of specimens): 74-6 (1) cf. Thelepus cincinnatus (FABRICIUS 1880) Stations (No of specimens): 74-6 (1) Distribution: cosmopolitan, m Records: Augener, 1932; Benham, 1927; Fauvel, 136; 1951; Hartman, 1952; 1966; 1967; Hartmann-Schröder & Rosenfeldt, 1989; 1991; Hessle, 1917; Levenstein, 1964; Monro, 1930; 1939; Willey, 1902 Thelepodinae sp. 1 Stations (No of specimens): 46-7 (7), 74-6 (1)

80 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 71 Terebellidae sp. 1 Stations (No of specimens): (1) Terebellidae sp. 2 Stations (No of specimens): 46-7 (1) Terebellidae sp. 3 Stations (No of specimens): 21-7 (1) Terebellidae sp. 4 Stations (No of specimens): 46-7 (1) Key to the Trichobranchidae MALMGREN 1866 Five species of Trichobranchidae have been found. Two genera could be identified without doubt, the taxonomy of two species remains unresolved. A total of 211 specimens were collected. 1 Four pairs of lanceolate branchiae. 16 thoracic chaetigers, uncini from chaetiger 4 Octobranchus only O. antarcticus # One single branchia of four lamellate branchial lobes (App.-Fig. 4G). 18 thoracic chaetigers, uncini from chaetiger 6..Terebellides Branchial lobes basally fused.t. stroemi Branchial lobes basally free..t. sp. 1BH

81 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 72 Annotated species list Octobranchus antarcticus MONRO 1936 Stations (No of specimens): 46-7 (1), (1), 74-6 (19), 80-9 (4), (119), (1) Distribution: Weddell Sea and Antarctic Peninsula, m Records: Hartman, 1966; 1967; Monro, 1936 Terebellides stroemi SARS 1835 Stations (No of specimens): 42-2 (1), 46-7 (2), (1), (1), 59-5 (1), 74-6 (6), 78-9 (12), 80-9 (5), 81-8 (2), (2), (1), (3), (15), (1), (6), (4) Distribution: cosmopolitan, m Records: Augener, 1932; Ehlers, 1897; 1900; 1908; Fauchald, 1972; Hartman, 1966; Hartmann-Schröder, 1996; Hessle, 1917; Holthe, 1986 cf. Terebellides sp. 1BH Stations (No of specimens): 80-9 (1) Trichobranchidae sp. 1 Stations (No of specimens): 46-7 (1) Trichobranchidae sp. 2 Stations (No of specimens): (1)

82 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION Descriptions of new species Ampharetidae MALMGREN Anobothrus pseudoampharete sp.n. Genus Anobothrus LEVINSEN 1884 Anobothrus pseudoampharete sp.n. Holotype. ANDEEP III, eastern Weddell Sea, st. 74-6, 20 February 2005, S, W, 1047 m, EBS, ZMH P Paratypes. ANDEEP III, eastern Weddell Sea, st. 74-6, 20 February 2005, S, W, 1047 m, EBS; 50 specimens, ZMH P Etymology. The name refers to the strong reminiscence of this species to Ampharete kerguelensis at first sight Diagnosis. The species can be recognized by the palae which are wide at the base and then abruptly tapering to a long, delicate tip. Description Holotype complete except for lack of branchiae, 5 mm long and 0.5 mm wide for 30 chaetigers. A species of median size, between 3 13 mm long. Body long, gradually tapering to the posterior end (Fig. 4A). Color in alcohol light tan to white. Prostomium slightly scoop-shaped, fused to peristomium and anterior segments. 15 thoracic chaetigers present, first bearig pairwise whirls of palae. Palae stout and broad at base suddenly tapering to a delicate tip (Fig. 4B). First two subsequent segments only with notopodia. Twelve thoracic uncinigers and up to 15 abdominal uncinigers. Fifth-to-last thoracic unciniger with elevated parapodia connected by a dorsal ridge, with modified chaetae and uncinigers (Fig. 4E, G). Thoracic chaetae limbate, of two sizes (Fig. 4D). Limbate chaetae of fifth to last chaetiger of three sizes plus some simple capillaries (Fig. 4E). Thoracic uncini with three rows of small teeth, laterally kidney shaped (Fig. 4F). Those of fifth-to last chaetiger also with three rows of teeth, more or less round in lateral view (Fig. 4G).

83 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 74 Abdominal uncinigers lacking notopodia, neuropodia with uncini with four rows of small teeth, one row of three teeth and one median main tooth (Fig. 4H). Pygidium with uneven margin, cirri lacking, anus terminal (Fig. 4A). Eight pairs of branchiae present, arranged in a row. Branchiae rather robust, digitiform (Fig. 4C), reaching back to about third chaetiger. Remarks. Only one further species of the genus Anobothrus LEVINSEN 1884 is known for the Southern Ocean to date. This species, A. gracilis (MALMGREN 1866), bears very long palae that gradually taper in width from base to tip. The palae of A. pseudoampharete n.sp. in contrast are shorter and very wide in their complete basal half. They suddenly taper to a fine, long tip in their distal half.

84 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 75 Fig. 4: Anobothrus pseudoampharete sp.n. A- lateral view, B- palae, C- branchiae, D- thoracic notochaetae, E- notochaetae 5 th -to-last thoracic segment, F- thoracic uncinus, G- thoracic uncinua 5 th -tolast segment, lateral and frontal view, H- abdominal uncini, lateral and frontal view

85 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION Hesionidae GRUBE Amphiduros serratus sp.n. Genus Amphiduros HARTMAN 1959 Amphiduros serratus sp.n. Holotype. ANDEEP I II, Weddell Sea, Antarctic Peninsula, Sta , 06 March 2002, 'S, 'W, m, EBS, ZMH P Paratypes. ANDEEP I II, Weddell Sea, Antarctic Peninsula, Sta , 06 March 2002, 'S, 'W, m, EBS, 1 specimens, ZMH P Additional material. ANDEEP I II, Weddell Sea, Antarctic Peninsula, Sta , 09 March 2002, 'S, 'W, m, EBS, 1 specimens Etymology. The name refers to the serration of the notopodial chaetae Diagnosis. Distinguishing characters of this species are the types of the notopodial (chambered and serrated) and neuropodial (composite, with chambered shafts) chaetae. Description Holotype incomplete, 3.0 mm long and 1.0 mm wide for 10 chaetigers. Antennae lost. Color in alcohol white.prostomium about as long as wide. Palps biarticulated with terminal article about twice as long as basal. Antennae short and delicate throughout, median antenna attached medially on prostomium. Peristomium dorsally reduced, laterally visible. Eyes absent. Tentactular cirri eight pairs, arranged as , all articulated. Length about that of body width (Fig. 5A). Parapodia biramous (Fig. 5B). Notopodium a short massive lobe, neuropodium longer, with a somewhat pointed tip. Dorsal cirri articulated, long, similar to tentacular cirri. Ventral cirri smooth, shorter, clearly extending tip of neuropodia. Notochaetae simple, chambered and serrated at distal margin (Fig. 5C). Neurochaetae composite falcigers with chambered shafts and long appendages with very delicate tips (Fig. 5D). Remarks. Amphiduros serratus sp.n. is the second species of the genus. It can clearly be distinguished by the absence of eyes and the form of the antennae. Amphiduros

86 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 77 fuscescens (MARENZELLER 1875) in contrast has large eyes and strongly tapering antennae with delicate tips (Pleijel, 2001) Micropodarke cylindripalpata sp.n. Genus Micropodarke OKUDA 1938 Micropodarke cylindripalpata sp.n. Holotype. ANDEEP I II, Scotia Sea northeast off Elephant Island, Sta. 46-7, 30 January 2002, S, W, 2889 m, EBS, ZMH P Paratypes. ANDEEP I II, Scotia Sea northeast off Elephant Island, Sta. 46-7, 30 January 2002, S, W, 2889 m, EBS, 2 specimens, ZMH P Additional material. ANDEEP I II, Scotia Sea northeast off Elephant Island, Sta. 42-2, 27 January 2002, S, W, m, EBS, 9 specimens Etymology. The name refers to the presence of pin-shaped biarticulated palps Diagnosis. The species can be recognized by the pin-shaped form of the palps in combination with the button-shaped tip of the parapodial lobes. Description Holotype incomplete, 3.0 mm long and 1.0 mm wide for 14 chaetigers. Color in alcohol white. Prostomium oval in shape, slightly wider than long. Palps biarticulated and pin-shaped. Two antennae, attached frontodorsally between palps. Peristomium indistinct, dorsally reduced. Everted pharynx with eleven distal papillae. Eyes absent (Fig. 6A). Body segmentation sutures indistinct, segmentation apparent due to parapodia arrangement. Six pairs of tentactular cirri on three segments, arranged in Cirri smooth, length about half the width of body. Parapodia uniramous (Fig. 6B). Parapodial lobe robust with somewhat button-shaped tip. Dorsal cirri resembling tentacular cirri in size and shape, ventral cirri similar, slightly shorter. Chaetae all composite falcigers with long appendages with very delicate tips (Fig. 6C). Chaetae arranged in dense fans.

87 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 78 Remarks. The species is the only species of the genus Micropodarke OKUDA 1938 described for the Southern Oceans so far and is thus easily recognized. The other only known species of this genus, M. dubia (HESSLE 1925), is only reported from temperate and tropic waters of the Pacific and Indic. Distinguishing characters of the species are the shape of the palpal articles and chaetal appendages Ophiodromus calligocervix sp.n. Genus Ophiodromus SARS 1862 Ophiodromus calligocervix sp.n. Holotype. ANDEEP I II, Weddell Sea, Antarctic Peninsula, Sta , 06 March 2002, 'S, 'W, m, EBS, ZMH P Paratypes. ANDEEP I II, Weddell Sea, Antarctic Peninsula, Sta , 06 March 2002, 'S, 'W, m, EBS, 1 specimens, ZMH P Additional material. ANDEEP I II, Weddell Sea, Antarctic Peninsula, Sta , 09 March 2002, 'S, 'W, m, EBS, 6 specimens Etymology. The name refers to the distinct dark coloring of the posterior end of the prostomium Diagnosis. The species can be recognized by the distinct coloring of the posterior margin of the prostomium that is mostly present in ethanol preservation. The round shape of the prostomium is also characteristic, even when antennae and tentacular cirri are lost. Description Holotype incomplete, 1.7 mm long and 0.5 mm wide for eight chaetigers. Color in alcohol white. Promstomium about as long as wide, almost round in shape. Three antennae, median one attached mediofrontally on prostomium. Palps biarticulated with basal article large and stout, terminal article of about equal length but more narrow. Peristomium well developed, dorsally reduced, laterally visible. Eyes absent (Fig. 5E). Boarder part between prostomium and peristomium distinctly colored, light brown in alcohol.

88 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 79 Six pairs of tentacular cirri, length about as body width, robust, often lost, on one to two visible segments. First chaetae in segment 2; parapodia biramous. Notopodia increasing in size from anterior to posterior. Neuropodia with a somewhat pointed tip (Fig. 5F). Dorsal and ventral cirri smooth, tapering to apex. Dorsal cirri about 1.5 times the length of neuropodia; ventral cirri shorter than neuropodia. Notochaetae simple capillaries, interiorly chambered (Fig. 5G). Neurochaetae composite falcigers; shaft of chaetae chambered, appendage long, about half as long as shaft, with very delicate tip (Fig. 5H). Remarks. The species seems very common and is easily recognized due to a dark transverse pigmentation on the dorsoposterior margin of the prostomium. In contrast to O. comatus (EHLERS 1912) which is found in the Southern Ocean deep sea as well, the species lacks eyes. Also the dorsal and ventral cirri are not as distinctly articulated in O. calligocervix n.sp. as in O. comatus Parasyllidea delicata sp.n. Genus Parasyllidea PETTIBONE 1961 Parasyllidea delicata sp.n. Holotype. ANDEEP III, Weddell Sea, Antarctic Peninsula, Sta , 18 March 2005, 'S, 'W, 3403 m, EBS, ZMH P Paratypes. ANDEEP III, Weddell Sea, Antarctic Peninsula, Sta , 18 March 2005, 'S, 'W, 3403 m, EBS, 2 specimens, ZMH P Additional material. ANDEEP III, Weddell Sea, South Orkney Islands, Sta , 20 March 2005, 'S, 'W, 1970 m, EBS, 5 specimens Etymology. The name refers to the delicate structure of the tentacular and dorsal cirri Diagnosis. The species can be recognized by its very delicate and long tentacular and dorsal cirri and the lack of eyes.

89 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 80 Description Holotype incomplete. Complete paratype of 29 chaetigers, 8 mm long and 1 mm wide. Color in alcohol white. Prostomium trapezoid, about as long as wide. Two antennae present, inserted frontally between the palps, very thin, about as long as first palpal article. Palps biarticulated with both articles long and slender. Pharynx smooth with fimbriated margin. Peristomium a slender ring, dorsally reduced. Eyes absent (Fig. 6D). Six pairs of tentacular cirri arranged in First five pairs slender and delicate, about as long as body width. Third dorsal pair more robust, even longer and indistinctly articulated. Parapodia uniramous, increasing in size towards middle of body, decreasing again towards pygidium. One acicula present ending in a stout tip. Dorsal and ventral cirri similar in shape, slender, dorsal cirri about 1.5 times as long as ventral cirri (Fig. 6F). Chaetae all composite falcigers in a dense fan. Appendages shortest at margins of parapodial lobe, increasing in size towards median tip of lobe (Fig. 6G). Pygidium a smooth ring, pointing terminally (Fig. 6E). Remarks. Parasyllidea delicata sp.n. is the only species of the genus Parasyllidea PETTIBONE 1961 described for the Southern Ocean so far. It is found in deep waters below 1000 m depth in contrast to P. australiensis HARTMANN-SCHRÖDER 1980, which is described for the Australian coast s sublitoral. The only other known species and type species of this genus, P. humesi PETTIBONE 1961 is a commensale species associated with the bivalve Tellina nymphalis (LAMARCK 1818) also known for shallow waters (Pettibone, 1961).

90 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 81 Fig. 5: A-D Amphiduros serratus sp.n. A-anterior segments, B- parapodium, C- notochaeta, D- neurochaeta. E-H Ophiodromus calligocervix sp.n. E-anterior segments, F- parapodium, G- notochaeta, H- neurochaeta

91 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 82 Fig. 6: A-C Micropodarke cylindripalpata sp.n. A-anterior segments, B- parapodium, C- neurochaeta, D-G Parasyllidea delicata sp.n. D-anterior segments, E- posterior segments, F- parapodium, G- neurochaeta

92 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION Opheliidae MALMGREN Ammotrypanella MCINTOSH 1879 Genus Ammotrypanella MCINTOSH 1879 Typespecies: A. arctica MCINTOSH 1879 Generic rediagnosis Body long and thin. Ventral groove along whole length of body. Prostomium bluntly rounded to conical with small palpode, peristomium indistinct. Eyes absent. Anterior parapodia button shaped with long, bent chaetae arranged in tufts. Parapodia embedded into lateral groove in median region, becoming more distinct in posterior region. Parapodia with branchiae in third quarter of body. Posterior chaetae longer than median ones, stiff and straight. All chaetae simple. Branchiae flat, wide at base, tapering to top. Posterior end of body laterally flattened with chaetigers reduced in length. Pygidium with or without anal tube, this with or without ventral cirrus Ammotrypanella arctica MCINTOSH 1879 Ammotrypanella arctica MCINTOSH 1879 Holotype. Davis Strait, Greenland (1785 fms), Globigerina ooze, H.M.S. Valerous, Sta. 16, N, W, 1875 (NHM, ) Additional material. ANDEEP I II, Scotia Sea northeast off Elephant Island, Sta. 42-2, 27 January 2002, S, W, m, EBS, 2 specimens, Weddell Sea, Antarctic Peninsula, Sta , 05 March 2002, S, W, m, EBS, 7 specimens, Sta , 09 March 2002, S, W, m, EBS, 1 specimen Additional records. Hartman & Fauchald (1971) A66, N, W, 2802 m; A70, N, W, 4680 m; A121, N, W, 4800m; A125, N, W, 4825 m; A122, N, W, 4833 m; A124, N, W, 4862 m; A120, N, W,

93 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION m; Ch84, N, W, 4749 m; Ch100, N, W, m Diagnosis. The species can be recognized by the characters of the anal tube which are the lack of a ventral cirrus and the presence of numerous short cirri on the posterior margin. Redescription Holotype incomplete, body long and thin, 15 mm long and 1 mm wide for 42 chaetigers. A moderately large species of 9 33 mm length and mm; number of chaetigers With ventral groove along whole length of body. Posterior body region laterally flattened. Color in alcohol white to a light tan. Prostomium conical with a short palpode. Peristomium a thin ring around the lips. Nuchal organs apparent as narrow lateral grooves, eyes absent (Fig. 7C-D). First following segment without chaetae. Anterior 8 10 parapodia button shaped with long, stiff chaetae in bushy fascicles. Following parapodia embedded in lateral groove. Posterior parapodia more distinct with long, straight chaetae. All chaetae simple. Branchiae can be present in chaetigers 22 32, all branchiae of similar length, flat with wide base, tapering to top. Posterior abranchiate chaetigers reduced in length, close to each other. Pygidium with anal tube; length of anal tube about that of last 5 8 chaetigers; posterior margin with numerous short cirri, without ventral cirrus (Fig. 7E). Remarks. A. arctica is the type species of the genus. The holotype is of poor condition, the diagnostic characters, however, are still present. Therefore it is without doubt that the newly found specimens from the Southern Ocean belong to this species Ammotrypanella cirrosa sp.n. Ammotrypanella cirrosa sp.n. Holotype. ANDEEP I II, Weddell Sea, Antarctic Peninsula, Sta , 05 March 2002, S, W, m, EBS, ZMH P-24751

94 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 85 Paratypes. ANDEEP I II; Weddell Sea, Antarctic Peninsula, Sta , 05 March 2002, S, W, m, EBS, 63 specimens, ZMH P Additional material. Sta , 09 March 2002, S, W, m, EBS, 2 specimens, Scotia Sea northeast off Elephant Island, Sta. 42-2, 27 January 2002, S, W, m, EBS, 4 specimens, South Sandwich Islands, east off Monatgu Island, Sta , 23 March 2002, S, W, m, EBS, 1 specimen Etymology. The name refers to the presence of numerous small cirri and a large ventral cirrus on the posterior margin of the anal tube. Diagnosis. The species can be recognized by the presence of a thick ventral cirrus and numerous small cirri on the posterior margin of the anal tube. Description Holotype complete, body long and thin, 16 mm long and 1.5 mm wide for 40 chaetigers. A median species of 7 25 mm length and mm; number of chaetigers Ventral groove present along whole length of body. Posterior body region bilaterally flattened. Color in alcohol white to a light tan. Prostomium conical ending in a short palpode. Peristomium indistinct, a thin ring around the lips. First subsequent segment without chaetae. Nuchal organs apparent as narrow grooves laterally, eyes absent (Fig. 7A). Anterior 7 8 parapodia button shaped, chaetae long, stiff, in bushy fascicles. Median parapodia embedded in lateral groove, becoming more distinct in posterior part of body; posterior chaetae long and straight. All chaetae simple. Branchiae flat with wide base, tapering to top; all of similar length; present in region from chaetigers 23 31, exact number variable. Posterior chaetigers shorter, close to each other. Pygidium with anal tube; length of anal tube about that of last 5 8 chaetigers; posterior margin with few short cirri; ventral cirrus robust, about half the length of anal tube (Fig. 7B). Remarks. The species is most similar to A. arctica. The most apparent diagnostic difference is the presence of a robust ventral cirrus on the anterior margin of the anal tube. Other than that the anal tube is very similar to that of A. arctica and recognition of

95 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 86 this species becomes difficult when the ventral cirrus is lost. In that case the structure of the branchiae can be considered, as they are less flattened and more robust than in A. arctica Ammotrypanella mcintoshi sp.n. Ammotrypanella mcintoshi sp.n. Holotype. ANDEEP III, st , Southern Atlantic, off South Africa, 26 January 2005, S, E, 4720 m, EBS, ZMH P Paratypes. ANDEEP III, st. 21-7, Southern Atlantic, 29 January 2005, 'S, 'E, 4574 m, EBS, 1 specimens, ANDEEP III, st. 59-5, Atlantic Sector Southern Ocean, 14 February 2005, 'S, 'W, 4651 m, EBS, 1 specimens, ZMH P Etymology. The name is chosen in honour of W.C. McIntosh who defined the genus Ammotrypanella in 1879 Diagnosis. The diagnostic character of this species is the lack of an anal tube. Description Holotype complete, body long and thin, 6 mm long and 0.5 mm wide for 35 chaetigers. A small species of 5 16 mm length and mm; number of chaetigers about or more, very variable. With ventral and lateral groove along whole length of body. Posterior body region bilaterally flattened. Color in alcohol white to a light tan. Prostomium conical, bearing a short palpode. Peristomium a thin ring around the lips. First subsequent segment apparent as a narrow ring from above, without chaetae. Nuchal organs indistinct narrow lateral grooves, eyes absent (Fig. 8A). Anterior 8 10 parapodia button shaped with long, stiff chaetae in bushy fascicles. Following parapodia indistinct, embedded in lateral groove. Posterior parapodia more distinct with long, straight chaetae. All chaetae simple capillaries. Branchiae present in third quarter of body, all of similar length, flat with wide base, tapering to top. Posterior abranchiate chaetigers reduced in length, close to each other. Pygidium without anal tube (Fig. 8B).

96 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 87 Remarks. The species is most similar to the type species of the genus Ammotrypanella MCINTOSH 1879, A. arctica. In contrast to all other species of the genus the species lacks an anal tube and thus can easily be recognized at first sight Ammotrypanella princessa sp.n. Ammotrypanella princessa sp.n. Holotype. ANDEEP I II, Weddell Sea, Antarctic Peninsula, Sta , 09 March 2002, S, W, m, EBS,ZMH P Paratypes. Scotia Sea northeast off Elephant Island, Sta. 42-2, 27 January 2002, S, W, m, EBS, 1 specimen, Weddell Sea, Antarctic Peninsula, Sta , 09 March 2002, S, W, 4678 m, EBS, 1 specimen, ZMH P Etymology. The name refers to the crown-shaped prostomium and the long, slightly bent chaetae along the anterior and median body that give the species a noble, feminine look. Diagnosis. Distinguishing characters of the species are the shape of the prostomium, the presence of relatively long chaetae in the median body region, and the smooth margin of the anal tube in combination with the presence of a ventral cirrus. Description Holotype complete, body long and thin, 11 mm long and 1 mm wide for 35 chaetigers. Length of species 5 11 mm, width about 02 1 mm; number of chaetigers With ventral groove along whole length of body. Posterior body region laterally flattened. Color in alcohol white to a light tan. Prostomium crown-shaped to conical, with a short palpode. Peristomium limited to the lips. First following segment achaetous. Nuchal organs apparent as lateral grooves, eyes absent (Fig. 7G). Anterior eight parapodia button-shaped with prolonged, stiff chaetae in bushy fascicles. Median parapodia less distinct, embedded in lateral groove, with few long, slightly bent chaetae. Posterior parapodia prominent, chaetae long and straight. All chaetae simple.

97 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 88 Branchiae present in various numbers in third quarter of body (about chaetigers 23 30), all of similar length, flat with wide base, tapering to top. Posterior abranchiate chaetigers reduced in length, close to each other. Pygidium with anal tube; about as long as last six chaetigers, opening slightly ventrally; posterior margin smooth, with short and stout ventral cirrus (Fig. 7F). Remarks. The species stands out by its median parapodia. These are more distinct than in A. arctica and A. cirrosa sp.n., with long, slightly bent chaetae. Therefore, the difference in chaetation between the anterior and median body region is less apparent. The prostomium is not completely conical, its form rather reminds of a crown. A. princessa sp.n. and A. cirrosa sp.n.have the ventral cirrus on the posterior margin of the anal tube in common. The margin of the anal tube, however, is smooth in A. princessa sp.n Ophelina Örsted, Ophelina ammotrypanella sp.n. Ophelina ammotrypanella sp.n. Holotype. ANDEEP I II; Weddell Sea, Antarctic Peninsula, Sta , 05 March 2002, S, W, m, EBS, ZMH P Paratypes. ANDEEP III, Weddell Sea, South Orkney Islands, Sta , 20 March 2005, 'S, 'W, 1970 m, EBS, 5 specimens, ZMH P Additional material. ANDEEP III, Weddell Sea, South Orkney Islands, Sta , 21 March 2005, 'S, 'W, 1178 m, EBS, 2 specimens Etymology. The name refers to the close resemblance of this species to Ammotrypanella arctica McIntosh, 1879 which only differs from it in the lack of branchiae in anterior and median segments. Diagnosis. The species can be recognized by the limtiation of enlarged branchiae to the third body quarter and an anal tube without a ventral cirrus.

98 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 89 Description Holotype complete, 30.5 mm long and 2 mm wide for 45 chaetigers. A large species of about mm length and 1 2 mm width for chaetigers. Color in alcohol a light tan. Prostomium conical with a distinct palpode. Peristomium forming a ring around the lips. Nuchal organs indistinct, but present. Eyes absent (Fig. 8E). First subsequent segment achaetous. Following segments with small, reduced parapodia. Anterior chaetigers with apparent annulation, this and segmental sutures fading towards median body region. Segmental sutures more apparent in posterior body region again. Chaetae simple capillaries throughout, anterior ones long and curved, median ones short, and posterior ones long and straight. Branchiae present in anterior and median chaetigers, very small and indistinct in first body half. Very large, somewhat limbate branchiae in third quarter of body, up to 15 of them present, lacking in posterior chaetigers. Posterior chaetigers laterally flattened and strongly decreasing in size. Pygidium with robust anal tube. Margin of this with numerous fine cirri, ventral cirrus lacking (Fig. 8F). Remarks. The species is most similar to O. setigera (HARTMAN 1978). Both species share the prolonged chaetae in anterior segments and the lack of an ventral cirrus on the anal tube. The anterior branchiae of O. ammotrypanella sp.n. are however smaller and less distinct than that of O. setigera, at first sight the species is therefore reminiscent of Ammotrypanella arctica Ophelina robusta sp.n. Ophelina robusta sp.n. Holotype. ANDEEP I II; Weddell Sea, Antarctic Peninsula, Sta , 05 March 2002, S, W, m, EBS, ZMH P Paratype. ANDEEP III, Weddell Sea, Sta , 14 March 2005, 'S, 'W, 2668 m, EBS, 5 specimens, ZMH P-24760

99 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 90 Etymology. The name refers to the presence of a very robust ventral cirrus on the anal tube. Diagnosis. A diagnostic character of this species is the presence of median sized branchiae in the first 7 8 parapodia. Enlarged branchiae are present in the posterior region of the body. The anal tube bears a robust ventral cirrus. Description Holotype complete, 18 mm long and 1.5 mm wide for 30 chaetigers. A species of median size. Length about mm, width 1 2 mm, number of chaetigers between Color in alcohol a light tan. Prostomium conical, carrying a distinct palpode. Peristomium limited to the lips. Nuchal organs present, but indistinct. Eyes absent (Fig. 8C). First follwing segment achaetous. Subsequent segments with reduced button-shaped parapodia. Anterior chaetigers with slight annulation. Segmental sutures indistinct in median body region becoming more apparent in posterior body region again. Chaetae simple capillaries throughout, anterior ones long and curved, median ones short, and posterior ones longer but few. Anterior 7 8 branchiae distinct, of median length. Very small and indistinct branchiae in median body region becoming long and flat in posterior part of body. Posterior chaetigers laterally flattened, terminally with an anal tube. Anal tube pseudoarticulated, bearing a robust ventral cirrus (Fig. 8D). Remarks. The species is similar to O. setigera and O. ammotrypanella sharing the presence of prolonged chaetae in anterior segments. It differs from both species by bearing a robust ventral cirrus on the anal tube. The anterior branchiae are larger than that of O. ammotrypanella, but still shorter than the posterior branchiae of both species.

100 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 91 Fig. 7: A-B Ammotrypanella cirrosa sp.n. A- entire animal, B- posterior segments, C-E Ammotrypanella arctica MCINTOSH 1879 C- anterior segments dorsal view, D- anterior segments lateral view, E- posterior segments, F-G Ammotrypanella princessa sp.n. F- posterior segments, G- anterior segments

101 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 92 Fig. 8: A-B Ammotrypanella mcintoshi sp.n. A- anterior segments, B- posterior segments, C-D Ophelina robusta sp.n, C- anterior segments, D- posterior segments E-F Ophelina ammotrypanella sp.n. E- anterior segments, F- posterior segments

102 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION Scalibregmatidae MALMGREN Pseudoscalibregma papilia sp.n. Genus Pseudoscalibregma ASHWORTH 1901 Pseudoscalibregma papilia sp.n. Holotype. ANDEEP I II, South Sandwich Islands, Sta , 23 March 2002, S, W, m, EBS, ZMH P Paratypes. ANDEEP I II, South Sandwich Islands, Sta , 23 March 2002, S, W, m, EBS, 2 specimens, ZMH P Additional material. ANDEEP I II, Scotia Sea northeast off Elephant Island, Sta. 42-2, 27 January 2002, S, W, m, EBS, 3 specimens, Scotia Sea northeast off Elephant Island, Sta. 46-7, 30 January 2002, S, W, 2889 m, EBS, 2 specimens Etymology. The species is named after the shape of the posterior parapodia which remind of butterfly wings. Diagnosis. The species can be recognized by prominent, almost foliose dorsal and ventral cirri in its posterior parapodia, distinctly rounded prostomial lobes and a rather smooth to irregularly wrinkled body surface. Description Holotype. complete, 6 mm long and 1 mm wide for 33 chaetigers. A moderately large species of 5 12 mm length and mm width. Number of chaetigers (Fig. 9A). Color in alcohol white to a light tan. Body sometimes expanded in anterior region to about chaetiger 12. Prostomium with two spherical lobes anterolaterally; no eyes, nuchal organs not apparent. Peristomium a single achaetous ring, well developed (Fig. 9B). Body surface almost smooth, sometimes irregularly wrinkled, a scheme in annulation not apparent. Anterior parapodia with reduced parapodial lobes, dorsal and ventral cirri, these rapidly increasing in size in median region; posterior dorsal and ventral cirri of large size, almost foliose, ventral cirri larger than dorsal ones; interramal sense organs missing (Fig. 9C).

103 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 94 All parapodia with simple chaetae; furcate chaetae with unequal tynes covered by fine hairs, present from chaetiger 2 (Fig. 9D). Pygidium terminal, formed by a ring of large tubercles carrying cirri of different lengths (Fig. 9E). Remarks. The species is most similar to P. bransfieldium (HARTMAN 1967) which is also very common in the Southern Ocean (Blake, 1981). They have in common the moderately large size and the lack of a schematic annulation (unlike P. ursapium e.g. which is covered by prominent tubercles). It can easily be distinguished from this species by the lack of a prominent nuchal organ dorsally on the prostomium, the distinctly spherical form of the anterolateral prostomial lobes, and the exceptionally large size of the posterior dorsal and ventral cirri Sphaerodoridae MALMGREN Ephesiella hartmanae sp.n. Genus Ephesiella Chamberlin, 1919 sensu Hartman & Fauchald, 1971 Ephesiella hartmanae sp.n. Holotype. ANDEEP I II, South Sandwich Islands, east off Monatgu Island, Sta , 25 March 2002, S, W, 774 m, EBS, ZMH P Paratypes. ANDEEP I II, South Sandwich Islands, east off Monatgu Island, Sta , 25 March 2002, S, W, 774 m, EBS, 2 specimens, ZMH P Etymology. The name refers to Olga Hartman, who contributed strongly to our knowledge about the Southern Ocean polychaetes through detailed and thorough taxonomic studies. Diagnosis. The species can be recognized by the limited number of segments of less than 50 and the lack of recurved hooks in the first parapodia. Description Holotype complete with 39 chaetigers. Length of body 4 mm, width 0.5 mm.

104 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 95 A small and thin species of 3 4 mm length and mm width for up to 40 chaetigers. Color in alcohol white to a light tan. Whole body, including prostomium and pygidium covered with numerous small tubercles. Prostomium with one median and one pair of lateral short antennae. One pair of tentacular cirri present. Eyes absent (Fig. 10A). Chaetigers with well developed parapodia. Dorsally with two lateral rows of macrotuberclese each bearing a small papilla on top. A distinct row of microtubercles dorsally to the macrotubercles. Parapodia uniramous with a well developed ventral cirrus reaching the tip of the parapodial lobe. A distinct prechaetal lobe dorsally on parapodium and a small postchaetal lobe present (Fig. 10F). Chaetae composite falcigers with short appendanges (Fig. 10C). Recurved hooks absent. Pygidium with two large bulbous like appendages similar to macrotubercles and two short cirri similar to microtubercles (Fig. 10B). Remarks. The species is the third species of this genus described for the Southern Ocean (Fauchald, 1974). In contrast to both other species from that region, E. antarctica (MCINTOSH 1885) and E. pallida FAUCHALD 1974, it lacks recurved hooks in the first parapodia. The chaetal appendages of E. hartmanae sp.n. are similar to those of E. antarctica, the number of segments is similar to E. pallida Sphaerodoropsis HARTMAN & FAUCHALD Sphaerodoropsis distincta sp.n. Sphaerodoropsis distincta sp.n. Holotype. ANDEEP I II, Scotia Sea northeast off Elephant Island, Sta. 46-7, 30 January, S, W, 2889 m, EBS, ZMH P Paratypes. ANDEEP I II, Scotia Sea northeast off Elephant Island, Sta. 46-7, 30 January, S, W, 2889 m, EBS, 5 specimens, ZMH P Etymology. The name refers to the well-defined and comparably large size of the macrotubercles.

105 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 96 Diagnosis. Diagnostic characters of this species are a distinct spherical and pronounced shape of the macrotubercles and the presence of two pairs of lateral antennae. Description Holotype complete, 2 mm long and 0.5 mm wide for 13 chaetigers. A delicate species of 1 4 mm length and mm width. Chaetigers number Body grub shaped, completely covered with fine tubercles (Fig. 10E). Color in alcohol white. Prostomium with one long median and two pairs of long lateral antennae. One pair of tentacular cirri of similar length present. Eyes absent. First chaetigers with reduced parapodia, subsequent parapodia well developed. Dorsum covered with four rows of dorsolateral macrotubercles. These strongly pronounced, spherical, sometimes distinctly white in color. Parapodia uniramous, dorsally smooth, ventrally with one small tubercle and a short ventral cirrus (Fig. 10D). One postchaetal lobe present. Parapodial lobe supported by one acicula. Chaetae composite with long falcigerous appendages (Fig 10G). Pygidium with two large bulbus like appendages, these spherical to triangular in shape (Fig. 10E). Remarks. At first sight the species seems to resemble S. parva (EHLERS 1913). The macrotubercles take the same position in S. distincta sp.n. as in S. parva, their outline is however more spherical and the size is larger in relation to total body size. In contrast to S. parva the species only bears two lateral antennae, and all antennae are comparably long Sphaerodoropsis maculata sp.n. Sphaerodoropsis maculata sp.n. Holotype. ANDEEP III, eastern Weddell Sea, st. 74-6, 20 January 2005, S, W, 1047 m, EBS, ZMH P Paratypes. ANDEEP III, eastern Weddell Sea, st. 74-6, 20 January 2005, S, W, 1047 m, EBS, 19 specimens, ZMH P-24768

106 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 97 Etymology. The name refers to the pigmentation of the body which is speckled with black to purple dots. Diagnosis. The macrotubercles are cone-shaped. The body is speckled with dark pigments. Three pairs of lateral antennae are present. Description Holotype complete, 3 mm long and 0.5 mm wide for 15 chaetigers. A small species up to 3 mm long and 0.5 mm wide for chaetigers. Body grub shaped, sparsely covered with distinct microtubercles. Distinct coloration due two numerous purple spots throughout the body that resist fixation in ethanol, rest of body white (Fig. 10H). Prostomium with long antennae, one median and three lateral pairs present. One additional pair of tentacular cirri present. Eyes indistinct brown dots dorsally on the prostomium, visible under high magnification. Dorsum with four pairs of lemon shaped macrotubercles and four rows of enlarged mircotubercles in addition to the smaller microtubercles. Parapodia of all chaetigers well developed with a distinct postchaetal lobe and a short ventral cirrus. No tubercles on parapodial lobes present (Fig. 10I). Chaetae composite with long falcigerous appendages (Fig. 10J). Pygidium with two large bulbous appendages of triangular shape, and a median, long cirrus (Fig. 10H). Remarks. The species stands out from all other species found in the deep Southern Ocean by a distinct pigmentation. The entire surface is spreckled with black to purple dots of various sizes. The prostomium bears a pair of light brown eyes that seem to vanish in fixation. The original position of the eyes can then only be determinde under a microscope. The macrotubercles are somewhat lemon to cone-shaped and not distinctly spherical as known for S. parva and S. distincta sp.n. Three pairs of lateral antennae are present

107 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION Sphaerodoropsis simplex sp.n. Sphaerodoropsis simplex sp.n. Holotype. ANDEEP I II, Scotia Sea northeast off Elephant Island, Sta. 46-7, 30 January, S, W, 2889 m, EBS, ZMH P Paratypes. ANDEEP I II, Scotia Sea northeast off Elephant Island, Sta. 46-7, 30 January, S, W, 2889 m, EBS, 21 specimens, ZMH P Etymology. The name refers to the weakly developed macrotubercles. Diagnosis. The species can be recognized by a stout body form and weakly pronounced macrotubercles in lateral position. Description Holotype complete, 1.5 mm long and 0.5 mm wide for 16 chaetigers. A small species with mm length and mm width for chaetigers. Body grub shaped, robust, completely covered with fine tubercles (Fig. 10K). Color in alcohol white. Prostomium with one median and two pairs of lateral antennae. One pair of tentacular cirri present. Eyes absent. Chaetigers with distinct parapodia, those of first chaetiger reduced. Dorsum covered with four rows of dorsolateral macrotubercles. These somewhat rectangular, only little pronounced. An additional transverse ridge formed by small mircotubercles across the dorsum (Fig. 10K). Parapodia uniramous, dorsally with two small tubercles. Ventral cirrus and postchaetal lobe short. Parapodial lobe supported by one acicula (Fig. 10M). Chaetae composite with short falcigerous appendages (Fig. 10L). Pygidium with two bulbous appendages and short anal cirri (Fig. 10K). Remarks. The shape of the macrotubercles is an outstanding characteristic of this species. It differs from that of other Southern Ocean species in being only little pronounced and almost square in outline. The body is more compact, almost a third as wide as long. The species general appearance is most similar to S. parva, the lack of a third pair of antennae however puts it closer to S. distincta sp.n.

108 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 99 Fig. 9: Pseudoscalibregma papilia sp.n. A- entire animal, B- anterior segments, C- posterior parapodium, D- furcate chaetae, E- pygidium

109 RESULTS COMMUNITY COMPOSITION & SPECIES IDENTIFICATION 100 Fig. 10: A-C, F Ephesiella hartmanae sp.n. A- anterior segments, B- posterior segments, C- composite chaeta, F- parapodium, D-E, G Sphaerodoropsis distincta sp.n. D- parapodium, E- entire animal, G- composite chaeta, H-I Sphaerodoropsis maculata sp.n. H- entire animal, I- parapodium, J-composite chaeta, K-M Sphaerodoropsis simplex sp.n. K- entire animal, L- composite chaeta, M- parapodium

110 RESULTS- COMMUNITY ANALYSES Univariate and multivariate community analyses Analysis of the epi- and supranet The EBS bears two nets for sampling, the epi- and the supranet. Samples from both nets were fixed, sorted and counted separately. Additionally, individuals found in the gear outside the nets were treated likewise and labeled with Ü (abbreviation for Überstand supernatant). For the expedition ANDEEP III all stations are represented by an epi- and a supranet. For ANDEEP I-II only the samples of station are complete. The other stations are represented by each one net only. In order to test the null hypothesis that there is no significant difference between the similarities of the nets of one station and that of different stations, a one-way ANOSIM was performed on the species assemblage matrix of ANDEEP III (standardized to 1000 m trawling distance). The result with R = shows (Fig. 11) that the null hypothesis can be rejected with a level of significance of 0.1 %. Fig. 11: Comparison of epi- and supranet similarities of EBS samples of ANDEEP III by means of oneway ANOSIM with 999 permutations

111 RESULTS- COMMUNITY ANALYSES 102 A standard operation of a student s t-test on the unstandardized family data of ANDEEP III (App.-Tab. 2) results in a rejection of the null hypothesis of % (degrees of freedom: 90, t = -2.58, standard deviation = 209). It is therefore statistically proven that the nets of one station are significantly more similar to each other than nets of different stations. For further analyses the nets of each station are since summed up and treated as one sample Species richness and biodiversity During the expeditions ANDEEP I, II and III a total of 14,176 polychaete specimens were sampled. The individuals were sorted into 47 different families (App.-Tab. 3). The most abundant families were the Spionidae, Hesionidae, Syllidae, and Polynoidae with more than 1000 individuals each (App.-Fig. 2A-B). Of the 47 families the Ampharetidae, Glyceridae, Goniadidae, Hesionidae, Nephtyidae, Nereididae, Opheliidae, Sabellariidae, Scalibregmatidae, Sphaerodoridae, Syllidae, Terebellidae, and Trichobranchidae have been determined to species level, 155 different species were distinguished. Based on the resulting species assemblage matrix for ANDEEP I-III a species accumulation plot has been drawn. The curve shows no saturation (Fig. 12) and consequently suggests an undersampling of the sampled areas. Fig. 12: Species accumulation plot based on species assemblage matrix of ANDEEP I-III

112 RESULTS- COMMUNITY ANALYSES Species richness (Margalef s Index) The great differences in sampling distance and sample volume between the stations of the expeditions ANDEEP I-III do not allow an analysis of the overall data volume by means of quantitative biodiversity measures as e.g. the Shannon Index. Therefore, the Margalef s Index for species richness [d] is chosen to compare all stations. This index relates the number of species (respectively families) with the number of individuals at each station. It does not consider the abundance of species (respectively family) the dependence on the sample volume is therefore distinctly weaker than for quantitative indices. Fig. 13 presents the Margalef s Index for all stations of ANDEEP I-III at family level. In addition, the trawling distances of station are shown. A correlation between the size of the sampled area and the family richness [d F ] is seen for stations within the Drake Passage (st. 41-3, 42-2, 46-7), the South Sandwich Trench (st , 143-1), near King George Island (st , 154-9), and within the central Weddell Sea (st , 132-2, 133-3, 134-4). This is evidence that the differences in family richness of stations within these regions might be biased by the trawling distances. No correlation is apparent for stations connecting the eastern Weddell Sea with the central Weddell Sea (st. 88-8, 94-14, , and 110-8). While the trawling distances decrease from east to west, family richness increases. The d F s of these stations are lower than that of stations near the eastern Weddell Sea coast (st. 74-6, 78-9, 80-9, 81-8) and that of st , 21-7 and 59-5 connecting the South Atlantic with the eastern Weddell Sea. The highest family richness is reported for the Drake Passage, the Southern Atlantic and Eastern Weddell Sea, and the area around the King George Islands with d F s > 3.8. Those of the central Weddell Sea lie between 1.6 and 3.7. The smallest family richness is found at st (d F = 0.9) positioned in the Drake Passage near Elephant Island. A similar picture is presented when the taxonomic level is elevated to the observation of species (Fig. 14). Correlation of species richness to trawling distances is found for the same areas as at family level. Also, st , 133-3, 134-4, and (central Weddell Sea), and st. 88-8, 94-14, , and on the transect between the central Weddell Sea and the eastern Weddell Sea show the lowest species richnesses of d S s < 4. High species richnesses are found at st (South Orkney Islands), (King-George

113 RESULTS- COMMUNITY ANALYSES 104 Island), 42-2 and 46-7 (Drake Passage), and st (eastern Weddell Sea). The highest value is found in the eastern Weddell Sea at station 74-6 [df = 9.2]. It is based on the smallest area sampled. The smallest d S s are found at stations (central Weddell Sea) and (near Elephant Island). Margalef's Index df traw ling distance (m) family richness trawling distance (m) station Fig. 13: Family richness for ANDEEP I-III-stations (Margalef s Index) Margalef's Index ds trawling distance (m) species richnes station trawling distance (m) Fig. 14: Species richness for ANDEEP I-III-stations (Margalef s Index)

114 RESULTS- COMMUNITY ANALYSES Biodiversity and Evenness Quantitative biodiversity measures are applied to the species data of the expedition ANDEEP III. In contrast to ANDEEP I/II the samples are complete, no vials were lost during transfer from the vessel to the home laboratories. Therefore, comparability of abundances can be achieved by standardization to 1000 m 2 sampling area (App.-Tab. 7). As biodiversity measures the Shannon Index and the Pielou s Evenness Index were chosen. Both indices have proven to be suitable for most benthic diversity data and are commonly used. Comparable data, especially of different taxa, is therefore available. During ANDEEP III a total of 10,635 specimens belonging to 46 different families were sampled. The most abundant families were the Spionidae, Hesionidae, Syllidae, and Polynoidae. The sampling volume ranged between 58 specimens (st , sampling area 3283 m 2, central Weddell Sea) and 4226 specimens (st , sampling area 1164 m 2, central Weddell Sea). Standardized to 1000 m 2 sampling area a theoretical total of 8471 specimens was sampled, the most abundant families being the same as in the unstandardized data. At family level the highest diversity (H > 2.5) is found in the Southern Atlantic (st , 21-7, 59-5), the eastern Weddell Sea (st. 78-9, 80-9, 81-8), and around King George Island (st ). The central Weddell Sea is clearly the least diverse area sampled (H = ). Within the central Weddell Sea the easternmost stations (st. 88-8, 94-14) are less diverse than that close to the Antarctic Peninsula (st , 142-5), resulting in an east to west gradient in family diversity. The least diverse station is st near Elephant Island with H = 0.3. The highest evenness is found at station in the western part of the central Weddell Sea with J = The lowest is found for station (Elephant Island, J = 0.2). Relatively similar values are found for stations from the Southern Atlantic to the eastern Weddell Sea with J = Evenness in the central Weddell Sea (st to 133-2) and around King George Island (st and 154-9) lies below J = 0.8. (Fig. 15). On a geographical scale species diversity is similar to family diversity (Fig. 16). The central Weddell Sea (st to 142-5) is less diverse than the easternmost and westernmost sites. Also, st is least diverse (H = 1.04). In comparison to family level, the differences between the diversity indices of the stations are more distinct. The

115 RESULTS- COMMUNITY ANALYSES 106 highest diversity is found at st (South Orkney Islands, H = 3.04), (South Africa, H = 3.02), 74-6 (eastern Weddell Sea, H = 3.0), and (King George Island, H = 2.87). The most diverse stations in the central Weddell Sea are st and (J = 2.59). Evenness is highest for st with J = With exception of st (J = 0.72), the evenness for stations from the Southern Atlantic and the eastern Weddell Sea ranges from J= 0.8 (st. 80-9, 81-8) and J= 0.92 (st ). Evenness of the central Weddell Sea (st to 142-5) ranges from J = , that of the King George Island stations are J = 0.76 (st ) and J = 0.89 (st ). Shannon Index/ Pielou's Evenness 3 2,5 2 1,5 1 0, Biodiversity and Evenness station J' H'(loge) S total families Fig. 15: Family diversity and evenness of ANDEEP III-stations (Shannon Index, Pielou s Evenness) Shannon Index/ Pielou's Evenness 3,5 3 2,5 2 1,5 1 0, Biodiversity and Evenness station J' H'(loge) S species total Fig. 16: Species diversity and evenness of ANDEEP III-stations (Shannon Index, Pielou s Evenness)

116 RESULTS- COMMUNITY ANALYSES Clustering and Multi Dimensional Scaling (MDS) With help of the Bray-Curtis Index similarities between different stations can be defined. These statistical numbers are presented in similarity resemblance matrices (App.-Tab. 8-10) based on which dendrograms of the relationships between stations (clustering) and two- to multidimensional plots (MDS) can be calculated to graphically visualize the similarities. In the following chapter cluster and MDS plots for all ANDEEP stations are presented ANDEEP I-III To minimize bias resulting from different trawling distances and sample volumes the species matrix was transformed to a presence/ absence matrix. After calculation of Bray-Curtis similarities, cluster and MDS analyses for the stations of ANDEEP I-III at species and family level were performed. Clustering of species results in eleven statistically supported groups with 1 11 stations (Fig. 17). The similarities between stations lie below 50 %. Geographical relations are not apparent in the analysis. The largest cluster with eleven stations includes stations of the Drake Passage (st. 42-2), the central Weddell Sea (st , , 131-1, and 134-4), and the eastern Weddell Sea (st. 78-9, ). Also, st and 59-5 between South Africa and the eastern Weddell Sea, and st and off King George Island are found in this main cluster. The MDS plot (Fig. 18) suggests the presence of one main clusters and six solitaire stations (st. 41-3, from the Drake Passage, and st , 133-3, 135-4, and from the central Weddell Sea). The remaining Weddell Sea stations (WS) and all eastern Weddell Sea stations (EWS) are concentrated in the upper part of the main clusters. Also within the WS and EWS sites stations 16-10, 21-7 (SA, Southern Atlantic), and 59-5 (EA, eastern Atlantic sector of the Southern Ocean), as well as the stations from King Georg Island (KGI), st and 154-9, are found, indicating high similarities between the polychaete assemblages in the Southern Atlantic, the Weddell Sea and west off the Antarctic Peninsula. Stations and from the South

117 RESULTS- COMMUNITY ANALYSES 108 Sandwich Trench (SST) and the stations of the Drake Passage and South Orkney Islands (DP, st and 46-7, SOI, st , 151-7) form the bottom part of the main cluster. They are less close to the WS and EWS stations than the SA, EA, and KGI stations. A clear formation of a separate clusters is, however, not apparent. Fig. 17: Cluster analysis of ANDEEP I-III-stations (pres/abs species matrix, Bray-Curtis similarities) Fig. 18: MDS plot of ANDEEP I-III-stations (pres/abs species matrix, Bray-Curtis similarities)

118 RESULTS- COMMUNITY ANALYSES 109 Clustering and MDS ordination of the family data result in a similarly weak resolution as that of the species data. Therefore only the MDS plot is presented (Fig. 19). A main cluster including the stations and (King George Island), stations 16-10, 21-7 and 59-5 (South Africa to Eastern Antarctica), stations and (South Sandwitch Trench), stations and (South Orkney Island), and some stations from the East and Central Weddell Sea (74-6, 78-9, 80-8, 81-8, , 131-3, 133-2) can be observed. The stations from the central and eastern Weddell Sea are positioned in the lower part of the ordination while the stations positioned closer to the Drake Passage lie in the upper part. Below the main cluster, stations 88-8, 94-14, , and 110-8, positioned on a transect connecting the eastern with the central Weddell Sea, form a small group, together with station (WS). These stations seem to be similar in their faunal composition. Also stations 132-2, and from the central Weddell Sea are positioned below the main cluster. Although these stations are not part of the main cluster, a close relation to the other stations from the Weddell Sea is evident. St (DP), in contrast, lies above the main cluster closer to the stations from the Drake Passage and the South Sandwich Trench. St (EI) is the station least similar to all other stations. A B Fig. 19. MDS plot of ANDEEP I-III-stations, A- entire, B- detail of main cluster (pres/abs family matrix, Bray-Curtis similarities)

119 RESULTS- COMMUNITY ANALYSES ANDEEP I/II As for the analysis of the ANDEEP I-III data, the species assemblage matrix of ANDEEP I/II was transformed to a presence/ absence matrix. After calculating the similarities by Bray-Curtis Index, cluster and MDS analyses at species level were performed. Cluster analysis (Fig. 20) of the species data results in two solitaire stations (st and from the Weddell Sea) and two statistically supported clusters. Both clusters include stations from the Weddell Sea, the Drake Passage, and the South Sandwich Trench. The similarities between stations lie below 40 %. This results in a poorly resolved MDS plot (Fig. 21). The ordination of stations seems rather random without clear groupings. It becomes apparent that the stations of the Weddell Sea (st to 134-5) are concentrated in the lower part of the plot, that of the Drake Passage (st. 41-3, 42-2, and 46-7) and the South Sandwich Trench (st and 143-1) in the central and upper part. Fig. 20: Cluster analysis of ANDEEP I/II-stations (pres/abs species matrix, Bray-Curtis similarities) A comparison of this result with station depths and the species matrices (Tab. 1, App.- Tab. 4) shows that all stations below 2000 m and with more than ten species cluster together (stations 131-3, 134-4, , 42-2, and 46-7). For better resolution of station similarities, MDS analysis is applied to an excerpt of these stations (Fig. 22). The

120 RESULTS- COMMUNITY ANALYSES 111 resulting plot indicates a relation between faunal composition and geographical position. Stations of the same basins (stations and from the Weddell Sea, stations 42-2 and 46-7 from the Drake Passage, and station from the South Sandwich Trench) are ordinated closest to each other. Additionally, similarities between the Drake Passage and the Weddell Sea are suggested. The similarities of the South Sandwich Trench (st ) to the Weddell Sea (st and 134-4) are lower than to the Drake Passage (st and 46-7). Fig. 21: MDS plot of ANDEEP I/II-stations (pres/abs species matrix, Bray-Curtis similarities) Fig. 22: MDS plot of ANDEEP I/II-stations deeper 2000 m and with at least ten different species (pres/abs species matrix, Bray-Curtis similarities)

121 RESULTS- COMMUNITY ANALYSES ANDEEP III Before calculation of the resemblance matrix for ANDEEP III (App.-Tab. 10), a fourth root overall transformation was used to strengthen the position of rare species and weaken that of very abundant species. The Bray-Curtis Index is then applied, cluster and MDS analyses are carried out. Cluster analysis results in four solitaire stations of which st (Drake Passage, near Elephant Island) is the one least similar to all others (Fig. 23). In addition, four clusters can be recognized. The first combines stations 74-6 from the eastern Weddell Sea and from the central Weddell Sea. In a second cluster station 21-7 from the Southern Atlantic, and st and between the eastern and central Weddell Sea are included. Both remaining clusters include stations from the Southern Atlantic, the eastern Weddell Sea, the central Weddell Sea, and off King George Island (western Antarctic Peninsula). Fig. 23: Cluster analysis of ANDEEP III-stations (standardized species matrix, Bray-Curtis similarities) The MDS plot (Fig. 24) supports the solitaire positions of stations 81-8 (EWS), (WS), (SOI), and (EI), and the high similarity between stations 74-6 (EWS) and (WS). All remaining stations are combined in one main cluster. In its lower part the South Atlantic stations (st , 21-7, and 59-5) group within stations

122 RESULTS- COMMUNITY ANALYSES 113 from the eastern Weddell Sea (st to 110-8). In the upper part the stations off King George Island (st and 154-9) and the South Orkney Islands (st ) cluster with stations of the eastern and central Weddell Sea (st. 78-9, 80-9 and ). Fig. 24: MDS plot of ANDEEP III-stations (standardized species matrix, Bray-Curtis similarities) Correlation of polychaete communities to environmental data (BIO-ENV) During the expeditions ANDEEP I/II data about sediment type at different sites were collected. Information are taken from Howe et al. (2004) and Diaz (2004) and presented in App.-Tab. 11. Taken into account are minimum and maximum grain size, water depth, and O 2 depth in the sediment layer. The grain sizes of stations 41-3, 42-2, 46-7, and were only expressed in words, not measures. Measures were therefore complemented through comparison of the overall description of these stations to other stations. In addition, O 2 depths for stations 41-3 and are unknown. A correlation of the ecological data with the species data of ANDEEP I/II is achieved with the Primer v function BIO-ENV (compare material and methods). The results give an idea which combination of environmental factors might play an important role in determining species composition of stations. Two different station combinations are analyzed. First all stations of ANDEEP I/II are considered. The station list is then

123 RESULTS- COMMUNITY ANALYSES 114 reduced to stations deeper than 2000 m and with at least ten species. The resulting five best matches and their significance level are presented in Tab. 2. Tab. 2: Most likely factor combinations explaining the species distribution of ANDEEP I-II, B 1- best match, to B 5- fifth best match, factors: minimum grain size (1), maximum grain size (2), water depth (3), O 2 depth (4) Station matrix B 1 B 2 B 3 B 4 B 5 Significance (%) All stations 4 3 1,3 3,4 1,3,4 29 Reduced stations 2,4 1,2,4 2 1, Considering all stations of the expedition, minimum grain size and water depth play an important role in the species distribution. Also O 2 depth has to be taken into account. After reducing the number of stations to those below 2000 m depth and with at least ten different species, grain size seems to be the most important factor. In analogy to the species assemblage matrices the family composition of stations is correlated to ecological factors. This is of interest because the family assemblage matrices consider all polychaete specimens found during the expedition, and therefore represent a more complete excerpt of the real community. During the analysis two different station lists are taken into account. First, all stations of ANDEEP I/II are included; second, all stations with less than ten species and 2000 m water depth are excluded. Tab. 3: Most likely factor combinations explaining the family distribution of ANDEEP I-II, B 1- best match, to B 5- fifth best match, factors: minimum grain size (1), maximum grain size (2), water depth (3), O 2 depth (4) Station matrix B 1 B 2 B 3 B 4 B 5 Significance (%) All stations 2 1,2 2,4 1,2, > 2000 m depth, min. 10 species 4 1,4 1 2,4 1,2,4 6 The significance level comparing all stations is very high (60 %), the results show no evidence for a relation between depth and family composition (Tab. 3). The significance

124 RESULTS- COMMUNITY ANALYSES 115 level of the reduced station list is distinctly lower. The excerpt of all stations below 2000 m and with at least ten species favors a correlation between sediment characters, especially minimum grain size and O 2 depths, to family composition Correlation of species to stations similarities (BV Step) In addition to the correlation to ecological factors, species composition can be correlated to a set of species that has the greatest influence on the similarities between stations by BV Step-analysis. Due to varying sampling volumes this analysis is only applied to the standardized data of ANDEEP III. The result (with a significance level of 1 %) suggests a set of 15 species to most likely determine the station similarities. These species are: Aglaophamus paramalmgreni, Ammotrypanella arctica, Ampharete kerguelensis, Amphicteis sp. 3, Kefersteinia fauveli, Kesun abyssorum, Micropodarke cylindricaudata sp.n., Ophelina ammotrypanella sp. n., Ophelina robusta sp.n., Ophiodromus calligocervix sp.n., Ophiodromus comatus, Polycirrus insignis, Pseudoscalibregma papilia sp.n., Sosanopsis kerguelensis and Travisia kerguelensis Average Taxonomic Distinctness (AvTD) and Variation in Taxonomic Distinctness (VarTD) The AvTD and the VarTD for all stations of ANDEEP I-III were calculated and are separately compared with an expected range (95 % significance range) based on a master list (all species found during ANDEEP I-III). The results are presented in two funnel plots. The AvTD funnel plot shows (Fig. 25) that stations 81-8 (eastern Weddell Sea), and (central Weddell Sea) have a significantly smaller average taxonomic distinctness, indicating that the species found at these stations are more closely related to each other than expected. The AvTDs of stations (Weddell Sea), 16-10, 78-9, and 74-6 (South Atlantic and eastern Weddell Sea) lie at the lower border of the

125 RESULTS- COMMUNITY ANALYSES 116 expected values for the according number of species. Stations 152-6, and (off Elephant Island and central Weddell Sea) show the highest AvTDs. Also stations (South Sandwich Trench) and 46-7 (Drake Passage) have AvTDs close to being significantly higher than expected. The VarTD shows almost the inverse result (Fig. 26) of the AvTD, both values being strongly negatively correlated in most cases. Stations and show a significantly higher VarTD than the expected values, with Λ + around 400 (expected value for Λ + between ). Also the VarTDs of stations 134-4, 110-8, 16-10, and 78-9 (South Atlantic, eastern and central Weddell Sea) lie above the 95 % significance range. Stations 81-8, and 74-6 (eastern and central Weddell Sea) have increased VarTDs, the increase being not significant. The lowest VarTDs are found for stations 152-6, and (off Elephant Island and central Weddell Sea). Due to the negative correlation of the results the joint analysis of AvTD and VarTD allows a better comparison of stations with the expected values (Fig. 27). Stations 152-6, and 134-5, that were at the border of being significantly different from the expected in the analyses above, now lie within their expected range. Also does station Stations 131-3, , 110-8, 81-8 (eastern and central Weddell Sea), and (South Atlantic) show significant difference, with values expected for stations with lower species abundances. Stations 42-2 (Drake Passage), 78-9 and 74-6 (eastern Weddell Sea), show expected values. All remaining stations have values significantly higher than the expected, indicating that the diversity of these stations is based on species that are less taxonomically related than expected.

126 RESULTS- COMMUNITY ANALYSES 117 Fig. 25: AvTD of ANDEEP I-III-stations (95 % significance range) Fig. 26: VarTD of ANDEEP I-III-stations (95 % significance range)

127 RESULTS- COMMUNITY ANALYSES 118 A B Fig. 27: AvTD/ VarTD- joint analysis for ANDEEP I-III-stations (95 % significance range), A- entire result, B- detail

128 RESULTS- VERTICAL AND GLOBAL DISTRIBUTION PATTERNS Zoogeography Vertical distribution patterns in the Southern Ocean The following results present the vertical distribution of the Southern Ocean deep-sea polychaetes collected during the expeditions ANDEEP I-III. App.-Fig. 5 illustrates the depth ranges in which species were found. The least number of species (15) is found at stations shallower than 1000 m depth. Of these, fourteen species are also found in deeper waters, only Axiokebuita millsi is limited to the shallow depth. Thirty species are only found in depths shallower than 3000 m, these include Gyptis incompta, Sphaerosyllis antarctica, Syllides articulosus, and all species of the genera Phisidia, Pista, and Typosyllis. A total of thirty-six species was collected from depths of 0 m to 5000 m, respectively 1000 m to 5000 m, and consequently can be considered eurybath species. The most abundant of these are Aglaophamus paramalmgreni, Aglaophamus trissophyllus, Anobothrus pseudoampharete sp. n., Glycera kergulensis, Kefersteinia fauveli, Ophelina breviata, Ophelina gymnopyge, Sosanopsis kerguelensis, Sphaerodoropsis parva, and Terebellides stroemi. Fifty-six species are exclusively found below 2000 m, fourteen of them being collected from below 3000 m and seven from below 4000 m. The depth range richest in species is that between m Global distribution patterns Global distribution patterns were compiled for all named species found during ANDEEP I-III including data from former records (compare chapter 2.4.2). New species are not included. App.-Tab. 12 gives the complete list of 84 species and a global distribution category. As shown in App.-Fig. 6, the distribution of the thirteen families analyzed is not limited to the Southern Ocean but covers all ocean basins world-wide. Most species records outside the Southern Ocean originate from Atlantic sites, especially from the Northern Atlantic. Records from the Pacific are mostly from the west coast of South and North

129 RESULTS- VERTICAL AND GLOBAL DISTRIBUTION PATTERNS 120 America, or from sites close to Australia. Records from the Indic are rare, maily due to an undersampling of this ocean. A separate view on the single families shows that distribution patterns differ distinctly at this taxonomic level. In the following an overview of the family distribution is given in alphabetical order. Characterized by a high number of species (thirteen named species are observed, all from different genera), the Ampharetidae are very wide spread with a clear tendency to being bipolar (App.-Fig. 8). Records from temperate waters are rare. The centre of distribution lies in subantarctic waters. Four cosmopolitan species are found (App.-Fig. 7A). Amphicteis gunneri, Melinna cristata, and Muggoides cinctus are recorded from northern-hemisphere waters with a connection to the Atlantic ocean, Anobothrus gracilis is additionally found in the North Pacific. Five species seem to be endemic to the Southern Ocean. Ampharete kerguelensis, Grubianella arctica, and Sosanopsis kerguelensis are additionally found at ANDEEP station in the eastern South Atlantic. The Glyeridae and Goniadidae are each represented by one species only in this analysis. While Glycera kerguelensis is restricted to the subantarctic region, Goniada maculata has been reported from Atlantic and Pacific sites in the northern hemisphere and from the Red Sea (App.-Fig. 9-10). The three hesionid species are mainly found in Antarctic and subantarctic waters, Gyptis incompta reaching into the South Pacific (App.-Fig. 11). A similar distribution is found for Nereis eugeniae, the only Nereididae included (App.-Fig. 12). A locally restricted distributional pattern is observed for the Nephtyidae that are only represented by the genus Aglaophamus (App.-Fig. 13). The Opheliidae are represented by two genera that show distinct differences in their distributional patterns. The species of the genus Ophelina are only recorded from the southernmost Atlantic and the Atlantic district of the Southern Ocean (App.-Fig. 14). Ophelina gymnopyge and O. scaphigera were to date only known for the Weddell Sea while O. breviata and O. nematoides have been reported for the subantarctic region. During the ANDEEP cruises these four species were additionally found at station north of the Antarctic Convergence. Ophelina setigera is reported from the Weddell Sea quadrant in the Southern Ocean, in addition records from the South Atlantic were found

130 RESULTS- VERTICAL AND GLOBAL DISTRIBUTION PATTERNS 121 in the Angola Basin (SE Atlantic, Ebbe, pers. comment).the second genus found is represented by Ammotrypanella arctica which has a clearly cosmopolitan distribution (App.-Fig. 7B). Only one sabellariid species is found (Phalacrostemma elegans) which is also known for southern and northern Atlantic waters (App.-Fig. 15). The most common distributional pattern within the Scalibregmatidae is a subantarctic one (App.-Fig. 16). Also two species restricted to the Weddel Sea are found, namley Oligobregma hartmanae and Sclerocheilus antarcticus (App.-Tab. 12). Travisia kerguelensis and T. lithophila are found throughout the Southern Ocean, T. lithophila is also recorded from the east Australian coasts. Hyboscolex equatorialis is reported for some sites at the pacific coasts of South America. Altogether three potentially cosmopolitan species are found (App.-Fig. 7C). Of these Scalibregma inflatum shows the distribution furthest spread, while Axiokebuita millsi and Axiokebuita minuta show a tendency to a bipolar distribution. Of the four sphaerodorid species, Sphaerodoropsis parva shows the widest distribution, being reported for the whole Southern hemisphere (App.-Tab. 12). Sphaerodoropsis polypapillata has so far only been recorded for the Weddell Sea, during this study new records from station are found. This is evidence for a South Atlantic distribution of this species (App.-Fig. 17). Ephesiella antarctica shows a circumpolar distribution while Clavorodum antarcticum seems to be endemic for the Weddell Sea (App.-Fig. 7D). The distibutional patterns within the Syllidae are very heterogenous. Of the 14 species found, six show a restricted distribution (App.-Fig. 7E), including both Sphaerosyllis species (Sphaerosyllis joinvillensis and Sphaerosyllis lateropapillata uteae) as well as Pionosyllis maxima and Pionosyllis epipharynx (App.-Fig. 18). Autolytus gibber and Proceraea mclearanus show a subantarctic and South Pacific distribution. In spite of the high number of locally restricted species, four cosmopolitan species are found with Braniella palpata, Exogone heterosetosa, Typosyllis hyalina, and Typosyllis variegata. The widest distribution of all families analyzed is discovered in the Terebellidae. Hereby a clear difference between the genera can be found. Most species are locally restricted (3 species) or subantarctic (11 species) (App.-Fig. 7F). Among these are the species of the genera Leaena, Thelepides, and Polycirrus (App.-Fig. 19). Only Leaena

131 RESULTS- VERTICAL AND GLOBAL DISTRIBUTION PATTERNS 122 collaris is found at station and thus north of the Antarctic Convergence. The genus Pista shows a far spread distribution, Pista cristata being a cosmopolite that is reported for the North Pacific, North Atlantic, as well as the Red Sea and the Mediterranean. Four further cosmopolitan species are found (Laphania boeckii, Hauchiella tribullata, Thelepus cincinnatus, and Proclea graffii), Laphania boeckii and Hauchiella tribullata are concentrated in polar waters of the Arctic and south of South Africa. A similar difference between the genera is observed within the Trichobranchidae. While Octobranchus antarcticus is restricted to the Weddell Sea, Terebellides stroemi is supposed to be a cosmopolitan species (App.-Fig. 20). Differences in species richness and diversity (Fig. 14, 16) give evidence that sites in the Drake Passage, around the Antarctic Peninsula, and the eastern Weddell Sea are influenced by adjacent ocean basins. These influences might be missing in the central Weddell Sea resulting in lower diversities. Additionally, clustering and MDS analyses presented under chapters indicate that stations from South Atlantic, eastern Weddell Sea and central Weddell Sea sites are closely related. The same applies to stations from the Drake Passage, off King George Island and the South Sandwich Trench. The results suggest the presence of an east to west gradient in polychaete composition in the Southern Ocean originating from different faunal influences from Atlantic and Pacific waters. If such a longitudinal gradient exists it should be reflected in an east to west shift in the distribution patterns of species found at eastern and western sites. Species known for Pacific waters are expected to be present in higher numbers at stations in the Drake Passage and around the Antarctic Peninsula. Similarly, species reported from Indic and eastern Southern Atlantic waters are mainly expected at eastern Weddell Sea sites. App.-Fig present the distribution charts for the regions as defined in the community analysis. No clear difference is found between distributional patterns of eastern and western sites. Species recorded for the South Pacific are found at all sites including those close to South Africa and in the eastern Weddell Sea. In return, species from the northern Atlantic have been collected from west of the Antarctic Peninsula. In contrast, it becomes obvious that with rising number

132 RESULTS- VERTICAL AND GLOBAL DISTRIBUTION PATTERNS 123 of stations per region and therefore of species per region the number of world-wide records changes but not the extent of the patterns. The same effect can be seen when comparing the global patterns for the different depth ranges as defined above (App.-Fig ). Depths between meter contain species from ocean basins world-wide. The four charts resulting are almost identical (App.-Fig ). Only the chart regarding the species found in depths shallower than 1000 m is different (App.-Fig. 30). Species records are exclusively found from southern hemisphere sites. The chart, however, is only based on one station. The species number included is smaller than that from the other depth ranges possibly causing the different pattern.

133 DISCUSSION Discussion 4.1 Efficiency of the gear and methods used for sampling The epibenthic sledge is constructed to function at any depth, and on soft sediment as well as primary hard substrate (Brenke, 2005). The width of the netboxes (1 m) allows an easy determination of the sampled area with given trawling distance. The mesh size of the net cones is 500 µm, plus an additional filter of 300 µm in the net buckets. This combination ensures the sampling of macrofaunal elements of all sizes while at the same time the bycatch of hugh sediment volumes is minimized. Valves and mechanically closing flaps secure the catch inside the net buckets and cone nets during heaving of the EBS (Brenke, 2005). Brenke (2005) gives instructions about the handling of the EBS and the calculation of the trawling distance. During the expedition ANDEEP I III these instructions were followed as closely as possible. Individual adjustments to weather and current conditions were carried out when required. The calculation of the trawling distance and the sampling area allows standardization of abundances to 1000 m 2 (Basford et al., 1989; Svavarsson et al, 1990; Brattegard & Fossa, 1991; Brandt, 1993; Brandt & Piepenburg, 1994). A quantitative comparability of qualitative data is achieved this way. Nevertheless, values have to be handled with great care since the EBS does not function without a systematic error. Brenke (2005) predicted a minimum systematic error of 25 % at all depths. He states, however, that this prediction is only preliminary. A higher number of deployments is needed to give a more adequate value. During his analysis of the deep-sea benthos of the Angola Basin Brenke (2005) also found out that there is no significant difference in the sampling result of the epi- and supranet. This is supported by the findings in this study. Neither at species level nor at family level a difference in the composition of net samples could be statistically proven. However, the sample volume of the epinet (7733 individuals) is distinctly larger than that of the supranet (2580 individuals). In comparison to the great box corer that is preferably used for gathering quantitative data, the EBS covers greater areas and thus samples a larger number of specimens (Tab. 4). The box corer is limited to a small sampling area of usually 0.25 m 2 per deployment. In addition, it creates a blast wave before touching the ground that represses large water masses and with them many epibenthic organisms. The chance to catch a nearly

134 DISCUSSION 125 representative extract of the species present seems more likely with an EBS. Due to its movement, the EBS catches part of the up-churned and repressed sediment and water masses, and also some organisms fleeing to the frontward direction of the gear. Tab. 4: Comparison of EBS and box corer deployments during ANDEEP I/II (Hilbig, 2004) area area station location depth [EBS] N [EBS] N [GKG] analyzed (m 2 ) analyzed (m 2 ) [EBS] [GKG] 42 Drake Passage 3690 m Drake Passage 2889 m Weddell Sea 3050 m Weddell Sea 2086 m Weddell Sea 1123 m Weddell Sea 4069 m South Sandwich Islands 2313 m However, the polychaete community sampled by the EBS seems in its structure very similar to that of box-corer samples known from former studies in the Southern Ocean. At ANDEEP I/II site 133 in the Weddell Sea Ampharetidae, Polynoidae, and Syllidae were among the most abundant families in EBS and in box corer samples (Hilbig, 2004). The polychaete communities also agree well with studies from different worldwide sites (App.-Tab. 13). Spionidae and Cirratulidae are known to be among the most abundant polychaete families in deep-sea communities. The same applies to scale worms as Polynoidae, and to some extent to Ampharetidae, Syllidae, and Opheliidae. Distinct differences from the expected are found for Pholoididae and Paraonidae. The Pholoididae are present in remarkably high numbers in some samples. Most findings originate from stations located around the Antarctic Peninsula, the Drake Passage, and the South Sandwich Trench. In the Weddell Sea only few Pholoididae are found. The family Pholoididae is only little studied to date. Therefore an explanation for this distribution cannot be given. The contribution of Paraonidae to the assemblages is rather low in the EBS samples. Paraonidae are known to be one of the most abundant polychaete families in the northern hemisphere (Cosso-Saradin et al., 1998; Glover et al., 2001; Thistle et al., 1985). The lack of their dominance in the Weddell Sea was already discovered in box-corer samples from ANDEEP I-II (Hilbig, 2004). Both studies indicate that Paraonidae are less important in the Southern Ocean deep sea than

135 DISCUSSION 126 in more temperate regions. A potential relation of these findings to the sampling method can be neglected. 4.2 Polychaete abundance and family composition Experiences from deep-sea basins from lower latitudes indicate that polychaetes make up around % of macrobenthic communtities in the deep sea (App.-Tab. 14). This study predicts a comparably smaller percentage of polychaete contributions to the samples of the ANDEEP expeditions. In comparison to the Polychaeta (10,635 individuals) peracaridan crustaceans were represented by 22,974 individuals in the EBS samples of ANDEEP III (Brökeland et al., submitted). An overview of the percentual invertebrate composition of the ANDEEP expeditions is not yet available. In the AGT samples the polychaetes contributed 19 % to all invertebrate individuals found (Linse et al., submitted). It has to be considered that the AGT is not constructed for the sampling of macrofaunal elements. An undersampling of the polychaetes is thus underlying this value. However, a reduced contribution of polychaetes in the Southern Ocean deep-sea benthos is not unexpected. Brandt & Schnack (1999) found an increased dominance of crustaceans in Arctic Seas near Greenland. On the basis of the recent database (App.- Tab. 14) a shift in dominance from Polychaeta to Crustacea with increasing latitude might be observed. Still, Polychaeta are one of the most flexible and successful invertebrate taxa in the deep seas. Their presence in large numbers and the finding of many cosmopolitan species in the ANDEEP samples indicate that the Southern Ocean deep sea is not as isolated in its faunal composition as the Antarctic shelf (Hilbig, 2004). A faunal exchange with lower latitude deep-sea basins is imaginable. The Antarctic Circumpolar Current (ACC), that is known to be one major distributional barrier between the Southern Ocean shelf and temperate waters, does not reach down into great depths. In contrast, the Antarctic deep water flows below into lower latitudes and can be identified as far north as the North Atlantic (e.g., Knox & Lowry, 1977). The family composition of polychaetes found in the Atlantic sector of the deep Southern Ocean shows some resemblance to that of other ocean basins (App.-Tab. 13). The

136 DISCUSSION 127 Spionidae are among the most abundant as are the Cirratulidae. Remarkable is the high abundance of Syllidae and Hesionidae in this study. Both are common, but usually not dominant families. The high abundance mainly originates from st (central Weddell Sea) and 74-6 (Eastern Weddell Sea). Both stations are characterized by high individual densities that are not found at adjacent sites. Cluster analysis indicates strong similarities of these stations (Fig. 17). A correlation of the polychaete assemblages of ANDEEP I-II with environmental factors (after Howe et al. (2004) and Diaz (2004)) suggests that family composition is strongly correlated to sediment grain size at sites. Comparable sediment parameters might be one explanation for the high similarities of st (eastern Weddell Sea) and (central Weddell Sea). Additionally, Syllidae are known to often be associated with sponges. Hilbig et al. (2006) found high syllid abundances on the southeastern Weddell Sea shelf and explained it by strong influences of epibenthic sponge communities. However, the AGT samples of ANDEEP III did not show increased numbers of sponges in the eastern Weddell Sea compared to the remaining stations (Linse et al, submitted). Further sampling is needed to investigate the unusual high abundance of syllids and hesionids. Remarkable family compositions are also found for stations 131-3, (central Weddell Sea), and (King George Island) where Opheliidae are most abundant. At station near Elephant Island almost exclusively Cirratulidae are present. The Cirratulidae all belong to one species. Specimens were surrounded by a dense fibrous material, presumably of organic origin. This is possible evidence for a special food fall or disturbance that favored the dominance of Cirratulidae at this station. Cirratulidae are typical pioneer polychaetes. They are able to fast settle in disturbed environment (e.g., Borowski & Thiel, 1998; Glover et al., 2001) and become very abundant. Rather typical deep-sea communities as known e.g. for the Atlantic deep sea are found at stations 59-5, 81-8, (Eastern and central Weddell Sea below 3000 m) and (South Orkney Islands, below 1000 m). Most abundant here are Spionidae, Cirratulidae (except for st ), Ampharetidae, as well as Paraonidae. The great depth range of these stations supports the result of the BIO-ENV-anlysis that depth is a subordinated factor determining polychaete family composition. Grain size and oxygene depth (after Howe et al. (2004) and Diaz (2004)) have been identified as more important. The great variety in family composition in the ANDEEP samples is probably

137 DISCUSSION 128 due to further ecological factors. Some of the different communities might present different successive stages of communities recovering from disturbance (e.g., eddies, iceberg rafting, sudden food input, lack of seasonal food input due to prolonged ice coverage).

138 DISCUSSION Species identification, composition and descriptions of new species Species identification was mainly carried out using monographs on Southern Ocean polychaetes (compare chapter 2.2). Original species descriptions were only consulted when identification with secondary literature were ambiguous. The risk of possible discontinuities in the naming of species remains when original descriptions are not regarded. However, the monographs are standard works and a high percentage of published studies rely on them. Their usage results in species lists of good comparability. In this study 155 species from 13 different families were distinguished. The families belong to four orders/ suborders (Glyceriformia, Nereidiformia, Opheliida, and Terebellida, taxonomy based on Fauchald, 1977) that differ in their life strategies. While Glyceriformia and Nereidiformia are vagile hunters, Opheliida are mainly endobenthic deposit feeders. The Terebellida are tube-dwelling suspension and deposit feeders. The 13 families make up 47 % of all specimens found in the analyzed samples. With a percentage of ~ 30 % the number of new species in the samples is comparable to that known from former studies in the Southern Ocean (Hartman, 1964; 1966;1967; 1978; Hartmann-Schröder & Rosenfeldt, 1988; 1989; 1990; 1991; 1992). Although the Southern Ocean has been subject to intensified sampling during the last century, this high amount of new species indicates an undersampling of the area. A percentage of ~ 46 % species found were formerly named. All of these have been recorded for the Southern Ocean before, although not necessarily in the same depths. It remains to verify that morphologically equal speciemens of different sites are members of one species. They might also be genetically separated cryptic species. Molecular studies on this topic are desirable. First attempts for crustacean and mulluscs have been made (e.g., Held, 2003; Held & Leese, 2007; Held & Wägele, 2005; Linse et al., 2007; Raupach & Wägele, 2006). In addition, Mincks & Glover (pers. comment) are working on Southern Ocean polychaete samples with special focus on Spionidae. The 155 species found during this study are included in new identification keys. The most recent, published monographs including keys for polychaetes of the Southern Ocean were presented by Hartman (1964; 1966; 1967, 1978). Since then a great number of new species has been described, but keys including these new species are not

139 DISCUSSION 130 published to date. The presented keys therefore represent an useful addition to recent taxonomic literature Species composition of families As mentioned, the Ampharetidae, together with the Terebellidae, are the most speciose family in the samples. Species are mostly present in low abundances. High abundances and a large distribution is limited to few species such as Sosanopsis kerguelensis, Anobothrus pseudoampharete sp. n., Ampharete kerguelensis, and species of the genus Amphicteis. Consequently, the Ampharetidae do not contribute dominant species to any station, although they are among the most abundant families at some stations (e.g., 16-10, 21-7 (South Atlantic), , (Weddell Sea)). The percentage of unknown and unidentified species within this family lies above 50 %. The weak knowledge of the ampharetid fauna of the deep Southern Ocean results from an undersampling of the area and often poor conditions of specimens after sampling. The drawn picture partially also applies to the Terebellidae. The family is not as abundant at single stations as Ampharetidae. Its high presence in the sum of all samples results from high abundances of Polycirrus insignis and Phisidia rubrolineata at station The particularities of this station have been discussed above. The Opheliidae and Scalibregmatidae are both present with median abundance and median diversity. The Opheliidae show a less even distribution than the Scalibregmatidae. They are very dominant at some stations (e.g., 131-3, , 154-9), although their high abundance is not due to dominance of single species as seen in the cases discussed above. The Trichobranchidae, Nephtyidae, Sphaerodoridae, and Glyceridae are present at most stations. However, only one to a few species are found. The Glyceridae are known to be a species rare family. In the samples, they are only represented by Glycera kerguelensis. For the Sphaerodoridae only Sphaerodoropsis parva is found in high abundance. Two species build the main community of the Nephtyidae (Aglaophamus paramalmgreni and A. trissophyllus) and the Trichobranchidae (Octobranchus antarcticus and Terebellides stroemi). While the determination of the nephtyid species is undoubted, it may be

140 DISCUSSION 131 possible that the two trichobranchid species are clusters of cryptic species. Trichobranchidae are only distinguished by few characters that are hard to determine in preserved species. For Terebellides stroemi a subspecies has already been described, differing in the shape of the uncini (T. stroemi kerguelensis). The Nephtyidae, as well as the Sphaerodoridae are considered basal polychaetes (see App.-Fig. 1). The species found are mainly endemic for the Southern Ocean. Therefore, these species are presumably not invaded species, high abundance of single species might be a sign of slow evolution rates. Also, a fast reaction to local food input is a possible explanation. The families Goniadidae, Nereididae and Sabellariidae are very rare, with low numbers of species. They seem to play a subordinated role in the Southen Ocean deep sea Descriptions of new species Descriptions of 15 new species were given in this study. In addition, the genus Ammotrypanella MCINTOSH 1879 was revised. Except for the hesionid genera Micropodarke and Parasyllidea, all genera were already known for the Southern Ocean. The formerly classified species of these two genera were only reported from northern hemisphere waters and southern hemisphere waters close to Australia Ampharetidae MALMGREN 1866 The only species of the genus Anobothrus LEVINSEN 1884 recorded for the Southern Ocean were A. gracilis (MALMGREN 1866) and A. patagonicus (KINBERG 1867) (Hartman, 1966; Parapar & San Martín, 1997). With A. pseudoampharete sp.n. a third Antarctic species is introduced. The former species A. antarcticus MONRO 1939 has been excluded from the genus by now, being the type species of a new genus, Anobothrella antarctica (MONRO 1939). Almost half of all species known for the genus are reported from the Southern Ocean. Anobothrus pseudoampharete sp.n. clearly differs from A. gracilis and A. patagonicus by the shape of its palae. These are similar

141 DISCUSSION 132 to that of Ampharete kerguelensis. Anobothrus gracilis bears very long, thin palae, that of A. patagonicus are small and similar to the notosetae (Hartman, 1966). The palae of A. pseudoampharete sp.n. are of median length with a broad base and a suddenly tapering, long delicate tip Hesionidae GRUBE 1850 Within the Hesionidae four species are newly described, all belonging to different genera. The genus Ophiodromus SARS 1861 has formerly been reported for the Southern Ocean with one species, Ophiodromus comatus (EHLERS 1913). The most apparent difference between this species and Ophiodromus calligocervix sp.n. is the presence of eyes in O. comatus. The tentacular cirri, as well as the doral cirri of O. calligocervix sp.n. are stouter. A distinct articulation of the dorsal cirri as known for O. comatus could not be discovered. The genus Amphiduros HARTMAN 1959 was originally believed to consist of five species. The holotypes of all formerly known species originated from northern hemisphere waters, specimens from Australia and Papua New Guinea were also recorded (Pleijel, 2001). Pleijel (2001) revised the genus. He excluded the species Amphiduros alensis BLAKE & HILBIG 1990 and formed a new genus Amphiduropsis. The remaining species were synonymized as A. fuscescens (MARENZELLER 1875). Amphiduros serratus sp.n. is consequently the second species of the genus at present time. It differs from the type species in the lack of eyes, also the tips of the antennae are less fine. While A. fuscescens is only reported from warm to temperate waters on both hemispheres, A. serratus sp.n. seems to be a cold water species of greater depths. Micropodarke cylindripalpata sp.n. is the second species described for the genus. As formerly Amphiduros, the genus Micropodarke OKUDA 1938 was revised by Pleijel & Rouse, They synonymized the formerly distinguished species M. dubia (HESSLE 1925), M. amemiyai OKUDA 1938, and M. trilobata HARTMANN-SCHRÖDER 1983, leaving M. dubia the only species. This species has a more or less cosmopolitan distribution. Records are present in temperate waters from the Pacific and Indic ocean, records from the Atlantic and polar regions are lacking. Micropodarke cylindripalpata

142 DISCUSSION 133 sp.n. is clearly different in its distribution pattern, being found in much colder waters and greater depths. Morphologically the two species differ in the shape of their palps. The second article of M. dubia is equal to the first while it is clearly thicker and pinshaped in M. cylindripalpata sp.n. The chaetal appendages of M. dubia are serrated while that of M. cylidripalpata sp.n. are smooth. Parasyllidea delicata sp.n. can be easily recognized by the lack of eyes. Both other species of this genus, P. humesi PETTIBONE 1961 and P. australiensis HARTMANN- SCHRÖDER 1980, bear four eyes. The chaetal appendages of P. delicata sp.n. end in a simple tip while they are bifid in P. australiensis. While P. delicata sp.n. is obviously adapted to cold waters, P. australiensis is reported for temperate waters of the Australian coast (Hartmann-Schröder & Hartmann, 1980). P. humesi was described to live in a commensale relationship associated with Tellina nymphalis (LAMARCK 1818), a bivalve known for shallow waters (Pettibone, 1961) Opheliidae MALMGREN 1867 The genus Ammotrypanella MCINTOSH 1879 was to date defined by the description of its only species A. arctica (McIntosh, 1879). According to McIntosh (1879), the main characters distinguishing it from Ophelina aulogaster (RATHKE 1843) are a bluntly rounded prostomium, bent silky bristles in the anterior seven to eight segments, median bristles sunk in lateral grooves, and short caudal segments with strong bristles. Fauchald (1977) summarized the generic characters of Ammotrypanella. In his monograph he defines the presence of two ventral cirri on the anal tube as a key feature of the genus. This character is, however, not present in the type species A. arctica which totally lacks a ventral cirrus. In contrast, McIntosh (1879) does not mention these ventral cirri. The finding of three new species of the genus enabled to rewrite the diagnosis and to define characters more clearly. The genus shows some plesiomorphic characters known for other opheliid genera such as Ophelina ÖRSTEDT 1843 and Antiobactrum CHAMBERLIN These characters are a long and thin habitus with a ventral groove, a conical prostomium with a palpode, and the possible presence of an anal tube with or without ventral cirrus.

143 DISCUSSION 134 Considered autapomorphies for Ammotrypanella are prolonged, bent setae in tufts in anterior parapodia in combination with a limitation of branchiae to the posterior body region. The type species A. arctica has been described from polar and temperate waters. Whether all records belong to this species has yet to be proven since the genus has been considered monotypic until now. It is, however, without doubt that the species has a bipolar distribution. The holotype originates from Arctic waters, the new records from Antarctic waters (App.-Fig. 14). Records of Hartman and Fauchald (1971) originate from a transect along the Hudson Canyon to Bermuda. Records of Fauvel (1914) and Levenstein (1978) do not represent specimens of A. arctica. Although both authors point out many similarities to the former description of McIntosh (1879), the specimens described present branchiae in the anterior and median body region. This character clearly excludes them from the genus Ammotrypanella. It is rather proposed that the specimens belong to the genus Ophelina. Comparing all four species of Ammotrypanella, it becomes apparent that the shape of the anal tube is the most distinguishing character within the genus. The presence of a ventral cirrus and the shape of the posterior margin of the anal tube occur in various combinations that clearly differentiate the species (Tab. 5). Tab. 5: Anal-tube characters of the species of Ammotrypanella MCINTOSH 1879 species posterior margin ventral cirrus A. arctica numerous fine anal cirri absent A. cirrosa numerous fine anal cirri present A. mcintoshi no anal tube no anal tube A. princessa smooth present Five of the ten species of the genus Ophelina found in this study are new to science. Two of them have been classified and described. Except for O. cylindricaudata (HANSEN 1878), all species formerly known for the Southern Ocean have been found in the samples proposing that the species of Ophelina have a common distribution, none of them can be considered rare species. In comparison to the most abundant opheliid species (O. breviata (EHLERS 1913), O. gymnopyge EHLERS 1908), and O. nematoides (EHLERS 1913)) the two new species are of rather large size, O. ammotrypanella sp.n. is

144 DISCUSSION 135 larger than 30 mm in some cases. Both new species are most similar to O. setigera HARTMAN 1978, sharing a robust body and prolonged anterior chaetae. The anterior chaetae of both species are distinctly shorter than described for O. setigera. Ophelina robusta sp.n. in addition bears a robust ventral cirrus on its anal tube Scalibregmatidae MALMGREN 1867 The new scalibregmatid species, Pseudoscalibregma papilia sp.n. is the 15 th scalibregmatid species known for Subantarctic and Antarctic waters. It can be distinguished from its most related species P. bransfieldium HARTMAN 1967 by an extraordinary well development of the dorsal and ventral cirri in the median and posterior parapodia, and the lack of a clearly apparent nuchal crest dorsally on the prostomium. Pseudosaclibregma papilia sp.n. is sampled from depths between 2889 and 3690 m, and therefore seems to represent a true deep-sea species. All together 12 of the 15 recorded scalibregmatid species from the Southern Ocean are found in the deep sea (Tab. 6), proposing that the Southern Ocean inhabits a highly divers scalibregmatid deep-sea fauna Sphaerodoridae MALMGREN 1867 The Sphaerodoridae were represented with 50 % of species undescribed in the samples. Especially the genus Sphaerodoropsis has grown after this study to a total number of 48 named species world wide. Known for the Southern Ocean are eight species including the formerly described S. arctowskyensis HARTMANN-SCHRÖDER & ROSENFELDT 1988, S. oculata FAUCHALD 1974, S. parva (EHLERS 1913), S. polypapillata HARTMANN- SCHRÖDER & ROSENFELDT 1988, and S. pyenos FAUCHALD 1974 (Hartman & Fauchald, 1971; Fauchald, 1974, Hartmann-Schröder & Rosenfeldt, 1988; 1990; 1992). Tab. 7 gives a comparison of the eight species concentrating on the most distinguishing

145 DISCUSSION 136 Tab. 6: Distribution of scalibregmatid species known for the Southern Ocean (after Blake, 1981; Schüller & Hilbig, 2007) Species distribution depth (m) Ascleirocheilus ashworthi BLAKE 1981 off Elephant Island west of Antipodes Island Hyboscolex equatorialis BLAKE 1981 Ecuador, Peru intertidal South Sandwich Trench Axiokebuita millsi POCKLINGTON & FOURNIER 1987 South Sandwich Trench Axiokebuita minuta HARTMAN 1967 South Shetland Islands South Orkney Islands Antarctic Peninsula Ross Sea Weddell Sea off Elephant Island South Sandwich Trench Oligobregma blakei SCHÜLLER & HILBIG 2007 off Elephant Island Drake Passage Oligobregma collare (LEVENSTEIN 1975) Ross Sea 6070 (?) Weddell Sea Bellinghausen Sea 2562 Oligobregma hartmanae BLAKE 1981 Weddell Sea 585 Oligobregma notiale BLAKE 1981 Antarctic Peninsula Ona Basin Weddell Sea Budd and Knox Coasts Ross Sea Oligobregma pseudocollare SCHÜLLER & HILBIG 2007 South Sandwic Trench off Elephant Island Weddell Sea Oligobregma quadrispinosa SCHÜLLER & HILBIG 2007 Ona Basin Weddell Sea South Sandwich Trench Pseudosaclibregma bransfieldium (HARTMAN 1967) Antarctic Peninsula Bransfield Strait Weddell Sea off Elephant Island Ona Basin South Sandwich Trench Ross Sea Pseudoscalibregma papilia n.sp. Ona Basin off Elephant Island South Sandwich Trench Ross Sea Pseudoscalibregma ursapium BLAKE 1981 Ona Basin off Elephamt Island Weddell Sea Scalibregma inflatum RATHKE 1843 cosmopolitan intertidal-abyssal Sclerocheilus antarcticus ASHWORTH 1915 Antarctic Peninsula Bransfield Strait

146 DISCUSSION 137 characters. These are the number of lateral antennae, the number of macrotubercle rows, and the parapodial structure. Tab. 7: Differentiating characters of species of the genus Sphaerodoropsis known for the Southern Ocean (after Fauchald, 1974; Hartmann-Schröder & Rosenfeldt, 1988; 1990; 1992) species Longitudinal Parapodial macrotubercle Lateral antennae Parapodial lobes papillae rows (max) S. arctowskyensis 7 3, short, oval post- & prechaetal 1 anterobasal S. distincta 4 2, long postchaetal 1 ventral S. maculata 4 3, long postchaetal none S. oculata 4 2, basally swollen prechaetal 1 median S. parva 4 3 prechaetal up to 8 S. polypapillata 9 3 prechaetal 1 anterior, 1 posterior S. pyenos 11 2 prechaetal, foliose unknown S. simplex 4 2 postchaetal 2 dorsal It becomes apparent that one group of species has four rows of macrotubercles on the dorsum, the number of rows in the other species is clearly higher. All newly described species are characterized by the presence of four rows. The number of lateral antennae is either two or three pairs in this genus. Within the group of species with four tubercle rows only S. parva and S. maculata sp.n. share the presence of three pairs of lateral antennae. They can clearly be distinguished by the shape of the parapodia, that of S. maculata sp.n. lacking papillae, and the presence of numerous colored spots on the entire surface of S. maculata sp.n. Of all species with two pairs of lateral antennae, S. distincta sp.n. stands out by the unusual pronouncation of its macrotubercles. These are greatly enlarged. In contrast, S. simplex sp.n. has small, somewhat flattened macrotubercles that are unusual for this genus. With its high number of species, the genus Sphaerodoropsis is the largest among the Sphaerodoridae. The variability in macrotubercle number and the presence of a large group of species with four rows suggests that the genus is a generic cluster. A careful revision of this group might lead to the formation of different genera for the known

147 DISCUSSION 138 species. Also the number of lateral antennae might play an important role in the definition of genera. The new species of the genus Ephesiella, E. hartmanae sp.n., can easily be recognized by the absence of recurved hooks in the first parapodium. The only species known with that trait is E. gallardi FAUCHALD It differs from E. hartmanae sp.n. in having two kinds of chaetae. E. gallardi is recorded from South Vietnam (Fauchald, 1974), further species known from the Southern Ocean are E. antarctica, E. mühlenhardtae HARTMANN-SCHRÖDER & ROSENFELDT 1988, and E. pallida FAUCHALD Apart from the difference in lacking recurved hooks in the first parapodia, the parapodial and chaetal structure of E. hartmanae sp.n. is different from that of these three species. E. hartmanae sp.n. bears a postchaetal and a prechaetal lobe (unlike E. antarctica), a papillation of the parapodial lobe is not apparent (unlike E. mühlenhardtae and E. pallida). Chaetae are composite with more or less smooth appendages (that of E. mühlenhardtae bear 4 6 teeth (Hartmann-Schröder & Rosenfeldt, 1988)) of median size (short in E. pallida).

148 DISCUSSION Polychaete diversity in the Southern Ocean As mentioned before, the samples of ANDEEP I/II are incomplete. This results in a reduction of the actual sample size and polychaete abundance for these stations. Due to the resemblance of the community structure in the epi- and supranet, a significant reduction in species richness is not expected. Analysis of the species assemblage matrices indicates that the deep Southern Ocean is still undersampled. The rising species accumulation plot proposes that the found number of species is lower than the expected. Continuing the graph to a maximum, a total number of about 180 species for the 13 analyzed families is expected (Fig. 28). Due to the great structuring of the Southern Ocean deep sea and the small area sampled this number is presumably still underpredicted. Fig. 28: Hypthetical course of the species accumulation plot resulting in a saturation (ANDEEP I-III) Biodiversity of all stations of the ANDEEP expeditions was calculated with the Margalef s Index. Additionally, the stations of ANDEEP III were standardized to achieve quantitative samples of 1000 m 2 sampling area. To this quantitative data the Shannon Index and Pielou s Evenness Index were applied. These indices are commonly used in biodiversity studies of different areas and invertebrate taxa, and comparability of the data is achieved. The Margalef s Index was applied to the species assemblage matrix, as well as to the family assemblage matrix of ANDEEP I-III. Families are taxonomic artefacts and not

149 DISCUSSION 140 comparable natural units. Biodiversity and systematic studies on families are therefore not favorable. However, for the present data analysis of family level is desirable for two reasons: At family level all polychaetes found during ANDEEP I-III are included while the species analyzed are limited to 13 families. In addition, polychaete families combine species of similar life forms and serve as indicators for ecological diversity. The environmental structure of areas as well as the occurrence of disturbances might therefore be easier detected by family diversity than species diversity. At family level diversity is highest on the transect between South Africa and the eastern Weddell Sea (st to 81-8) and off King George Island on the western side of the Antarctic Peninsula (st and 154-9). The lowest diversity was found at stations connecting the eastern Weddell Sea with the sites close to the Antarctic Peninsula (st to 110-8). Also the central Weddell Sea shows comparably low diversities (ANDEEP III st and 133-2, ANDEEP I/II st ). A correlation of low diversities with trawling distance and depth can be neglected. Trawling distances were greatest on the transect between the eastern and central Weddell Sea, decreased diversity is thus not due to reduced sample volumes. Stations in the central Weddell Sea were located between 1123 m (st ) and 4928 m (st. 88-8) depth, depths of the Southern Atlantic and eastern Weddell Sea stations ranged from 1047 m (st. 74-6) to 4720 m (st ). Nevertheless, the result is not unexpected. The analysis of isopod samples from ANDEEP I/II also resulted in the lowest diversity in the central Weddell Sea with the exception of st (Brandt et al., 2004). In addition, Hilbig et al (2006) reported lower polychaete diversity in the deep Weddell Sea than on the south eastern Weddell Sea shelf and the Antarctic Peninsula region. Brandt et al. (2005) explained increased species richness for Isopoda in the Antarctic Peninsula region and off the South Shetland Islands by possible faunal exchanges with South American benthic communities. This could also apply to the polychaete fauna and lead to increased family diversity around the Antarctic Peninsula. Influences from the Southern Atlantic might serve as an explanation for high diversities at stations in the eastern Weddell Sea. The lowest diversity was found at st More than 94 % of all specimens found, belong to one cirratulid species. A possible explanation was already given in chapter 4.2.

150 DISCUSSION 141 At species level the differences between stations are more distinct than at family level. While the geographical differences found for the family diversity are also recognized at species level it becomes apparent that some stations are more divers than others. The most divers stations are st and st in the Drake Passage, st in the eastern Weddell Sea, st off South Orkney Islands, and st near King George Island. The high diversity at stations in the Drake Passage might be due to the joining of different water masses in this area. The Drake Passage is the southernmost connection between the Pacific and the Atlantic Ocean. Faunal elements of both oceans are found in this region. Also, the Antarctic bottom water formed in the Weddell Sea passes the Drake Passage, before entering the South Atlantic. Some species are found in the Drake Passage and in the Atlantic or Pacific ocean, but not in the Weddell Sea (e.g., Phalacrostemma elegans, Hauchiella tribullata, or Proclea graffii). Other species are present in the Drake Passage and in the Weddell Sea, and further records from the Atlantic or Pacific are known. Among those are Ampharete kerguelensis, Amphicteis gunneri, Ammytropanella arctica, Axiokebuita minuta, Sphaerodoropsis parva, and Terebellides stroemi. The Drake Passage consequently combines polychaete species recorded from three ocean basins, explaining the high diversity found. The remaining stations pointed out above are all located on the continental slope that begins in depths of approximately 600 m in the Southern Ocean. The continental slope serves as a direct faunal connection between shelf and abyssal plain. Unlike temperate oceans with steep temperature gradients, the continental slope of the Southern Ocean offers a potential habitat for species of great depth ranges from the abyssal plain as well as from the shelf. The vertical distribution patterns of the species analyzed support the impression that eurybathy is a common trait among polychaetes in the Southern Ocean (App.-Fig. 5, see also Hilbig, 2004; Hilbig & Blake, 2006, Hilbig et al. 2006). High diversity of the slope stations is therefore evidence for the presence of faunal elements from shelf and deep-sea communities. In addition, sedimentation rates are higher on the slope than in the abyss. An increase in food input might also account for increased diversity on the continental slope.

151 DISCUSSION 142 The Shannon Index applied on the standardized family and species assemblage matrices of ANDEEP III, supports the impression that the central Weddell Sea is the least divers region sampled. Within the central Weddell Sea an increase in diversity from eastern (st. 88-8) to western stations (st ) can be observed. Hilbig et al. (2006) assumed that differences found in polychaete communities originate from differences in food income. The Antarctic Peninsula region is known to be very productive. Primary production in the Southern Ocean is highest during the austral summer when the ice cover breaks apart to form the pack ice and a sufficient amount of light is available. A decrease in diversity from the western to the eastern Weddell Sea sites might be correlated to a decrease in primary production with increasing distance to the Antarctic Peninsula. The highest species diversity is found at st off South Orkney Islands and st in the South Atlantic. These stations do not have remarkably high species abundances. The highest species abundances are found at st (eastern Weddell Sea) and (central Weddell Sea). However, the evenness of these stations is lower than that of st and explaining lower diversities. Station is characterized by the dominance of single species (e.g., Phisidia rubrolineata, Polycirrus insignis, Syllides articulosus, Gyptis incompta); at st Anobothrus pseudoampharete sp.n., Sphaerodoropsis parva, and Sphaerosyllis lateropapillata uteae are the most abundant species found. In general, evenness is not apparently correlated to geographical regions. Differences in evenness are presumably explained by local differences of sites. On a general scale, the diversity of the Southern Ocean deep-sea polychaetes in this study is comparable to that of former studies from the Southern Ocean and other ocean basins. Hilbig et al. (2006) found diversity values of and higher and an evenness between for stations in the eastern Weddell Sea and around the Antarctic Peninsula. Hilbig and Blake (2006) report polychaete diversities between (Shannon Index) and an evenness of 0.5 and upper for shelf to deep-sea stations off the Gulf of Farallones, north-eastern Pacific. Compared to different invertebrate taxa the polychaete diversity is equally high or even higher, underlining the importance of polychaetes for benthic communities. The diversity of isopods from ANDEEP I/II EBS samples ranged between 1.71 and 3.62 with an evenness of above 0.5 (Brandt et al., 2004). This supports the common idea that polychaetes are among the most robust

152 DISCUSSION 143 invertebrate taxa with a very high tolerance towards great depth ranges, extreme environments, and disturbance (Hilbig & Blake, 2006). In conclusion, the results give evidence that depth is not a limiting factor for polychaete diversity in the deep Southern Ocean. A reduced input of food due to a strong seasonality in primary production and low sedimentation rates, are more likely to influence the diversity patterns within the central Weddell Sea. In addition, faunal exchanges with adjacent ocean basins might lead to increased diversities in the eastern Weddell Sea, the Drake Passage, and the western side of the Antarctic Peninsula. 4.5 Similarities between sampling areas All cluster analyses clearly differentiate st from all other stations. The peculiarities of this station have been discussed formerly. It is therefore excluded from further discussions. In general, similarities are comparably low, lying below 60 % in all analyses. This might be due to an undersampling of the area. Further data will presumably result in more distinct similarity patterns. Clustering of all samples of ANDEEP I-III at family level and at species level show that the stations of the Southern Atlantic (st , 21-7 and 59-9) and off King George Island (st , 154-9) cluster within stations from the eastern and central Weddell Sea. Most stations are located in one main cluster. Within this cluster geographical ranges can be identified. At family level the stations of the eastern Weddell Sea and the Southern Atlantic are concentrated on one side of the cluster. Stations off King George Island are closer to the Drake Passage and off the South Orkney Islands on the other side of the cluster. The central Weddell Sea stations are found on both sides. A similar ordination is found at species level. A difference is found for the stations off King George Island that are more similar to the eastern Weddell Sea sites than to the Drake Passage in this analysis. Clustering of the standardized species data of ANDEEP III also indicates a strong resemblance of sites off King George Island and the Southern Atlantic to the eastern and central Weddell Sea. A similar clustering of stations in the Weddell Sea and Drake

153 DISCUSSION 144 Passage is found in a former study by Hilbig et al. (2006). The material in that study originated from box corer samples taken during the EASIZ II expedition (1998) to the eastern Weddell Sea shelf, deep-sea sites in the eastern Weddell Sea and stations around the Antarctic Peninsula and the Drake Passage. The authors distinguished three different groups, the Peninsula shelf group (including three sites of the eastern Weddell shelf), the deep station group and the south-eastern Weddell Sea shelf group. It has formerly been noticed that stations 74-6 (eastern Weddell Sea) and (central Weddell Sea) share the highest family and species abundances. Clustering and MDS plots indicate high similarities of these stations. Both stations are located on the continental slope. However, st lies at the east coast of the Weddell Sea while st is a north-western Weddell Sea site. A faunal overlap of shelf stations from the eastern Weddell Sea and the Antarctic Peninsula has formerly been reported (Hilbig et al., 2006). This supports the idea that the sampled area hosts a more or less uniform faunal assemblage that underlies local variations due to different depths and abiotic factors. The presence of the similar faunal compositions near the east coast and the west coast of the Weddell Sea can be explained by two models (Fig. 29): Fig. 29: Possible ways of polychaete dispersal within the Weddell Sea (Southern Ocean)

154 DISCUSSION 145 Model one proposes a connection through the Weddell shelf with a distribution along the coastlines. Dispersal is most likely from east to west due to clockwise currents in the Weddell Sea. Polychaetes are not very vagile, an active distribution over long distances against current systems is not probable. The second possibility is a connection through the deep Weddell Sea. As mentioned earlier, eurybathy is a common trait among polychaetes in the Southern Ocean. Submergence of shelf and slope species to deeper waters at the east and the west coast of the Weddell Sea by down-slope currents is very likely, followed by a subsequent transport across the Weddell abyssal plain by the Antarctic bottom water. Few individuals could have been able to emerge to lower depths in both parts of the Weddell Sea again, in spite of a lack of currents in that direction. Emergence against current direction has already been reported for isopods in the Southern Ocean (Brandt et al., 2004). The higher abundance of species in the coastal zones might result from the fact that the deep sea is not the optimal habitat for submerging shallow water species. They are able to survive and reproduce there but not as successfully as on the continental slope and shelf. Both models are supported by the data of this study. A great number of species are present at stations 74-6 and and are lacking on the Weddell abyssal plain. Among these are Gyptis incompta, Kefersteinia fauveli, Leaena collaris, Polycirrus insignis, Sphaerosyllis joinvillensis, Sphaerosyllis lateropapillata uteae, Syllides articulosus, and Travisia kerguelensis. All of these species occur in comparably high abundance and can not be considered rare species. A lack of records in the Weddell Sea abyss therefore indicates absence in that area. Species found in high numbers at stations 74-6 and and in lower numbers in the deep Weddell Sea are e.g., Amage sculpta, Amphicteis gracilis, Axiokebuita minuta, Neosabellides elongatus, Ophiodromus comatus, and Terebellides stroemi. Regarding this, a connection of the two sites through the abyssal plain seems possible. The dataset is evidence for emergence but does not prove it. The presence of species on the shelf of both coastal sides of the Weddell Sea and in the abyssal plain might also result from distribution along the shelf and submergence of species into the deep sea. From the analysis of ANDEEP I/II stations it becomes apparent that the Weddell Sea stations (st , 134-4) group together as do the stations from the Drake Passage (st.

155 DISCUSSION , 46-7). St is more similar to the Drake Passage than to the Weddell Sea. A possible explanation of that pattern is the flow of the Antarctic bottom water. The Antarctic bottom water originates from the Weddell abyssal plain. It enters the Drake Passage and flows past the South Sandwich Trench into the Southern Atlantic. With it, faunal elements from the deep Weddell Sea might be transported into the South Atlantic, decreasing in number with distance. Consequently, the Weddell Sea stations are more similar to Drake Passage stations than to stations of the South Sandwich Trench. Furthermore, the South Sandwich Trench and Drake Passage stations might share some Atlantic and even Pacific elements that are rare in the Weddell Sea. The similarity analyses show that the Atlantic sector of the Southern Ocean seems to host a potentially uniform poylchaete fauna. Geographical gradients between eastern and western sites, as known from former studies (Hilbig et al., 2006) are present. However, these are only indistinct and based on low similarities. The differences in polychaete composition found for different station are presumably rather due to local differences of environmental factors and events of disturbance. Also, it becomes evident that the Weddell deep sea is not isolated from the Southern Atlantic. A faunal exchange between the basins occurs, which is not hindered by the Antarctic Circumpolar Current. The ACC does not reach into these depths and therefore cannot be considered a distributional barrier for the Antarctic deep-sea fauna (Brandt et al., 2006). 4.6 Influence of environmental factors and species on similarities The Bray-Curtis Index is based on the presence and abundance of species to determine the similarities between stations. Some species thus have a greater impact on the similarities than others. These are not necessarily the most abundant species, but species that show distinct differences in their distribution within the samples. The species determined to have the greatest impact in the similarities of the ANDEEP III stations were Aglaophamus paramalmgreni, Ammotrypanella arctica, Ampharete kerguelensis, Amphicteis sp. 3, Kefersteinia fauveli, Kesun abyssorum, Micropodarke cylindripalpata sp.n., Ophelina ammotrypanella sp.n., Ophelina robusta sp.n., Ophiodromus

156 DISCUSSION 147 calligocervix sp.n., Ophiodromus comatus, Polycirrus insignis, Pseudoscalibregma papilia sp.n., Sosanopsis kerguelensis, and Travisia kerguelensis. Among these species five are vagile predators; four of them belong to the Hesionidae. Syllidae, the most speciose vagile family in the samples, is not among them. The stated filter feeders are all but one Ampharetidae. The suspension feeders are to equal parts Opheliidae and Scalibregmatidae. Those families might hence be of high ecological importance, reacting towards environmental changes not by being present or absent but by changes in their species composition. Of all species stated, only Ophiodromus calligocervix sp.n., Polycirrus insignis, and Travisia kerguelensis are present in depths shallower than 1000 m. Amphicteis sp. 3, Ophelina robusta sp.n., Polycirrus insignis,and Pseudoscalibregma papilia sp.n. are only present above 4000 m. The depth ranges of the species are very wide, proposing that eurybath species have the strongest influence on similarities of stations. This results in a weakening of the importance of depth as a differentiation factor for stations below 1000 m. This finding is also supported by the BIO-ENV analysis of the ANDEEP I/II stations. The results show that depths is the most important factor when station (774m depth) is included. After the exclusion of this slope station, the grain size and oxygen availability in the sediment are more likely explanations for station similarities. Sedimentary parameters regarded in this study are taken from Howe et al. (2004) and Day (2004). The data originate from the expeditions ANDEEP I/II and were taken directly at the sample sites. The coarsest sediment was found in the South Sandwich Trench (st and 143-1) with silty sand (35-40 µm) to pebble of up to 235 µm grain size. The environment is energetic with stronger currents and higher sedimentation rates compared to the Drake Passage and Weddell Sea sites. Up to 28 polychaete families have been found at the sites (st ), indicating a strongly structured environment. The polychaete community at these stations is dominated by Spionidae, a pioneer taxon typical for disturbed environments. Also, vagile hunters and deposit feeders are present. Because of their higher vagility or burrowing abilities they have an advantage to suspension feeders on coarse and mobile sediment. Grain sizes in the Drake Passage are slightly larger than in the Weddell Sea. In the Drake Passage the highest number of different families has been found (16-33 families per station). As for the South Sandwich Trench, vagile hunters are present in high abundance. Also

157 DISCUSSION 148 Spionidae and Cirratulidae, both indicators for disturbances, are among the most abundant families. Further burrowing deposit feeders and suspension feeders play a subordinated role. In the finer sediments in the Weddell Sea with slower sedimentation rates, suspension and deposit feeders dominate the polychaete communities. Pioneer taxa as Spionidae and Cirratulidae are less abundant. At st the highest number of families is reported for this region with 18 families. As suggested by the BIO-ENV analysis, a high correlation between the grain size and the polychaete composition is observed. Coarse sediment results in highly structured communities dominated by vagile families. Vagile hunters need hard surfaces to crawl on and approach their prey. The abundance of pioneer taxa indicates disturbance events. Fine sediments, in contrast, favor the presence of suspension feeders; these are less vagile and more sensitive towards fast sedimentation. Also deposit feeders are abundant in fine sediments; they are mostly burrowing forms that easily move through fine sediments. The general importance of grain size in contrast to depth was already reported by Bilyard and Carey (1979) for polychaete compositions in the western Beaufort Sea. It thus seems to be a global characteristic rather than one specific for the Southern Ocean. 4.7 Taxonomic diversity Most stations show a taxonomic diversity that lies among or above the expected. The expected value is calculated based on a masterlist including all species found in this study. The species accumulation plot has shown that the area is strongly undersampled. The masterlist is consequently shorter than expected. This might explain why strong differences to expected AvTDs and VarTDs have not been found for the samples. St has been formerly pointed out to be peculiar, its taxonomic diversity lies far below the expected. The same applies to st The station is characterized by low abundances. However, the samples of this station are incomplete; the result is therefore strongly biased. Surprisingly, st and in the central Weddell Sea show values below the expected although they are among the most speciose stations. This can be explained by the species composition which is dominated by Hesionidae (only st ), and species of Oligobregma and Ophelina. At st species of the genera

158 DISCUSSION 149 Ammotrypanella, Oligobregma, and Ophelina dominate the community. The AvTD is therefore distinctly lower than expected for stations with comparable species numbers. Both stations seem to present an environment that favors the presence of Opheliidae and Scalibregmatidae. Both families probably underwent radiation events in some genera in the Southern Ocean, among which Ophelina and Oligobregma are very successful. At the mentioned stations species of both genera co-exist, proposing that conditions are optimal and interspecific competition is strongly reduced.

159 DISCUSSION Zoogeography and vertical distribution Origin of the Southern Ocean deep-sea fauna During the early Triassic (245 Ma ago) the continent of Antarctica was imbedded in Gondwana. It had direct connections to the recent South America, South Africa, India and Australia. During the Jurrasic and the early Cretaceous, Gondwana broke apart and the continent of Antarctica slowly moved southwards. While it isolated from South America, Africa and India, the Australian continent was still closely attached to Antarctica. A first gap between Antarctica and Australia occured during the late Cretaceous. In the following 50 M years, the gaps between the Antarctic continent and the other continental plates enlarged and Antarctica reached the approximate southern position it has today (after Smith et al., 1994). About M years ago the Drake Passage opened into deep depths, allowing the ACC to develop (Lawver & Gahagan, 2003; Lawver et al., 1992). Barker (2001) postulated an even younger date of the deep opening and the origin of the ACC. The glaciation of Antarctica and the cooling of the deep ocean first started in the Eocene- Oligocene boundary about 34 M years ago (Barker & Thomas, 2004). It was not abrupt but interrupted by several interglacial phases (Lear et al, 2000). The cooling of the Weddell Sea and the Antarctic Peninsula was supported by the Weddell Gyre which transported cold water masses and ice to the Antarctic Peninsula. The ACC resulted in an isolation of the cold water masses around the Antarctic continent and supported the glaciation process (Barker & Thomas, 2004). Although the wind-driven ACC needs a constant deep-sea connection to exist, it does not reach down to the sea floor. The Weddell Sea Bottom Water slowly flows northwards beneath the ACC, similar deep-water flows exist in the Pacific and Indic ocean (Barker & Thomas, 2004). The development of the Antarctic continent and the Southern Ocean had several consequences for the fauna and flora on land and in the sea. The extreme cooling resulted in a great extinction of species. Some species were able to adapt to this extreme environment and in course of the isolation, underwent numerous radiation events. The adaptation to cold temperatures on the shelf facilitated a submergence of species into the deep sea. Submergence helped the species escape from the glaciation of the shelf

160 DISCUSSION 151 and resulting disturbances from down-slope transport of glaciogenic depris (Thatje et al., 2005). During the process of submergence species, however, had to adjust to increased pressure and reduced food input. The glaciation of the Antarctic continent and its surrounding waters did not have such dramatic consequences for the deep-sea fauna. The deep sea of the Southern Ocean has constant temperatures around 2 C and is hence as cold as the deep sea world wide. It is thus proposed that part of the Southern Ocean deep-sea fauna originates from submerging shelf species while also relict species occur. Additionally, the ACC does not isolate the Southern Ocean deep sea from adjacent ocean basins. It is imaginable that part of the deep-sea fauna secondarily invaded the Southern Ocean from temperate deep-sea basins Vertical distribution The vertical distribution patterns show that most polychaete species in the Southern Ocean have wide depth ranges. Species limited to stations above 1000 m are rare. Most species are found between 1000 and 3000 m. In depths between 2000 and 3000 m, a faunal break occurs. Below 3000 m species are found that do not occur in shallower samples. At the same time some species found above 2000 m do not occur below. The result indicates that eurybathy is a common trait among Southern Ocean deep-sea polychaetes. At the same time classical shelf and deep-sea faunas exist. Three categories of polychaetes are found: shelf species, deep-sea species that only occur below 3000 m, and eurybath species. The Southern Ocean is characterized by a deep shelf (down to m) and lack of temperature isoclines. It is therefore a common idea that submergence of shelf species and emergence of deep-sea species is facilitated within most invertebrate groups. Evidence for the Isopoda is given by Brandt, 1991, Brandt et al., 2004, and Brandt et al., The Antarctic shelf fauna is reported to be isolated. It is characterized by high species richness and a high percentage of endemism that originates from radiation events after the cooling of the Antarctic continent (Arntz et al, 1997; Barnes & de Grave, 2000; 2001; Brandt et al., 2004; Crame, 2000; de Broyer et al., 2002; Gray,

161 DISCUSSION ) ~ 34 Mio years ago (Barker & Thomas, 2004). This model seems to fit to many invertebrate taxa such as Isopoda. For Isopoda, large depth ranges as found for Polychaeta are reported (Brandt et al., 2006). However, recent studies have presented new evidence that eurybathy is not a special characteristic of polychaetes in the Southern Ocean but is rather common among polychaetes world wide (Brandt et al.; 2006; Hilbig & Blake, 2006; Hilbig et al. 2006). This supports the idea that the Southern Ocean deep-sea poylchaete community does not originate only from relict and submerging shelf species. The far vertical distribution is evidence for a secondary invasion of the Antarctic deep sea from adjacent ocean basins such as the Pacific or Atlantic Global distribution patterns A faunal exchange between the Southern Ocean deep sea and adjacent deep-sea basins is strongly supported by the global distribution patterns found for some polychaete species in this study. No difference could be determined between different depth zones. Species communities from the continental slope (1000 to 3000 m) show as far a distribution as species from the deep sea. Many species found are spread far beyond the subantarctic region while others are more or less regionally restricted. Distinct differences between the families analyzed can be seen. The species of the Goniadidae, Glyceridae, Nereididae, and Nephtyidae show distribution patterns centred in the Southern Ocean. However, only few species were found for these families. The genera, in contrast to the species are reported for all ocean basins world wide (e.g., several species of Goniada, Glycera, and Nereis are known for the Northern Atlantic (e.g., Hartman, 1950; Hartmann-Schröder, 1996)). These records might support the theory of a faunal exchange between temperate deep-sea basins and the Southern Ocean. After invasion of species of these genera into the Southern Ocean, speciation could have resulted in the evolution of locally restricted species. A second possibility is that the found species originate from relict species. It is not determinable if species of the same genera already lived on the Antarctic plates and speciation took place during glaciation, or if they invaded the Southern Ocean after the cooling.

162 DISCUSSION 153 The hesionid species found are also only reported from the Southern Ocean. They are present in higher abundance and with more species than the formerly mentioned families. It might be a general characteristic of Hesionidae that most species do not have wide distribution ranges. However, the genera of the Hesionidae found are also known for other ocean basins Amphiduros fuscescens (MARENZELLER 1875), Parasyllidea humesi PETTIBONE 1961, and P. australiensis HARTMANN-SCHRÖDER 1980 are reported from temperate waters of both hemispheres (Hartmann-Schröder, 1980; Pettibone, 1961; Pleijel, 2001). As for the formerly stated families, the sampled hesionid species therefore either evolved from relict species, or from species that invaded the Southern Ocean after glaciation. A remarkable pattern is observed for the Trichobranchidae. Only two named species were found in the samples. While Terebellides stroemi is a cosmopolitan species, Octobranchus antarcticus is endemic for the Southern Ocean. The Trichobranchidae resemble the Ampharetidae and Terebellidae in their morphology and feeding strategy. All three families are tube dwelling, selective suspension feeders that use long tentacles to catch particles from the water column and the sediment surface. The tubes are usually partially imbedded in the sediment, and the animals are known to leave them sometimes. The three families also have similar distribution patterns. Locally restricted and cosmopolitan species are found in the Southern Ocean. An explanation might be found in the great variances in reproductive strategies. Wilson (1991) reports brooding and free swimming larvae (lecithotrophy or direct development) for the Ampharetidae and Terebellidae. Also encapsulation of embryos in gelatinous masses is reported for some Terebellidae and for the cosmopolitan trichobranchid T. stroemi. Free swimming larvae with direct development presumably settle close to their place of hatching. The larvae need to feed shortly after hatching. However, dispersal over large distances aggravates feeding. In addition, larvae are put at risk of mechanical disturbance and declined conditions. Lecithotrophy of larvae and encapsulation of embryos in contrast permit widespread dispersal of species. The cosmopolitan species Melinna cristata e.g., has free-living lecitotrophic larvae (Wilson, 1991). Especially the encapsulation in gelatinous masses might be an advantage when the brood is drifted away. It might protect embryos from mechanical disturbance and changing abiotic factors during development, and reduce embryo mortality.

163 DISCUSSION 154 Similar distributional patterns are found for Scalibregmatidae and Opheliidae. For both families species with wide-spread distributions and locally restricted species are found. The two families are very similar in their life strategies and presumably closely related (Rouse & Fauchald, 1997). Their high abundance in samples world wide (e.g., Glover et al., 2001) suggests a high adaptive ability to different environments. The Opheliidae have free-living larval stages (Wilson, 1991). Distribution of larvae by bottom-near currents and settlement of species in different localities are likely. Wide distribution areas for the Opheliidae are not surprising. Larval development of the Scalibregmatidae is not known. However, the cosmopolitan distribution of some species suggests distribution by larval dispersal. Both families are burrowing forms. A second way of species distribution might be dispersal of adult specimens. Benthic storms (eddies) and turbidity currents (Scheltemar, 1994) are common phenomena in the Southern Ocean deep sea. Adult specimens might be carried away with the sediment. Substrate heterogeneity is supposedly less distinct on the abyssal plains than in shallow waters. Thus specimens surviving the dispersal might be able to settle at different localities afterwards. Rouse & Fauchald (1997) on basis of cladistic analyses proposed that Opheliidae and Scalibregmatidae are basal forms. The high age of these families would be an additional explanatory factor for the wide distribution of species. Because of the high number of endemic species in the Southern Ocean, these probably originate from local speciation events. A subsequent invasion into the Pacific Ocean via the Humboldt Current and into the Atlantic via the Antarctic bottom water can be postulated for some species (e.g., Hyboscolex equatorialis, Ammotrypanella arctic, and the genus Axiokebuita). The similarities in life strategies might have an influence on the similarities of distribution patterns a phenomenom already discussed for Ampharetidae, Terebellidae, and Trichobranchidae. The difference of Opheliidae and Scalibregmatidae to the formerly discussed is the fact that the classification of species within these families is not as reliable as in the other families. The genera Travisia and Kesun were formerly believed to be opheliid genera (e.g., Hartman, 1966; Fauchald, 1977). Persson & Pleijel (2005) however stated that Travisia is a scalibregmatid genus. The close resemblance of Kesun to Travisia leads to the assumption that Kesun is also a scalibregmatid genus. In addition, the identification of Axiokebutia millsi, A. minuta and

164 DISCUSSION 155 Scalibregma inflatum might not be correct for all records. This leads to a general problem of the analysis of global distribution patterns. Potential misidentifications and discontinuities in naming in the historical data can bias the analyses. Since most species in this study are well studied and only records from taxonomic publications are considered, the risk of bias is reduced. The species of the Sphaerodoridae are primarily restricted to the Subantarctic region. Only Sphaerodoropsis parva has been reported for the Southern Pacific and the South Atlantic. This species is the most abundant sphaerodorid species in the samples. It supposedly originates from the Southern Ocean and invades lower latitudes via the Humboldt Current and the Antarctic bottom water. The Sphaerodoridae are vagile, omnivorous forms that contribute around 2 5 % to all polychaete species in different areas of continental slopes and abyssal plains, with low abundances (< 1 % of individuals). Within the family free-living larvae are found, the existance of lecithotrophic larvae is predicted (Fauchald, 1977). The combination of free larval stages (potentially high dispersal rates), presence of only few speciose genera in the Southern Ocean, and narrow distribution ranges at species level indicates that the Sphaerodoridae are highly adapted to certain environmental niches. Within the Southern Ocean several speciation events might have occurred resulting in the high number of endemic species. The Syllidae are also vagile, omnivorous forms. Most species are brooders (Wilson, 1991). Brooding is reported for almost all genera found in the samples, thus dispersal of species through larval stages is very unlikely. Most species show restricted distributions; especially the species of the genus Sphaerosyllis seem to be endemic for the Weddell Sea and originate from local radiation events. The reproduction strategy of the genus Typosyllis is unknown. This genus contributes two of the four cosmopolitan syllid species found. An explanation for a cosmopolitan distribution of syllid species cannot be given; a secondary invasion of the Southern Ocean by these species is likely. The results are congruent with the common observation that the distribution potential of species is related to the reproduction and environmental robustness of species. Free larval stages contribute to the dispersal of species (e.g., Grahame & Branch, 1985). Lecithotrophic larvae with prolonged planctonic stages might favor great dispersal even in waters of low nutrient content. They are often found in the deep sea (e.g., Herring,

165 DISCUSSION ). In addition, adults of species with high environmental robustness might be able to settle in new localities after being carried away with sediment transport. Brooding seems to be more common in species of narrow distribution as found for the Syllidae. The cosmopolitan distribution of some species is an indication for secondary invasion of these species into the Southern Ocean after glaciation. Typosyllis variegata, Terebellides stroemi, Melinna cristata, and Scalibregma inflatum for example are reported for depths from the shelf down into the deep sea in oceans world wide. Their distribution patterns are patchy. Distinct distributional directions from the Southern Ocean into adjacent basins as found for some Scalibregmatidae or Sphaerodoropsis parva are not apparent (App.-Fig ). The Southern Ocean is of a comparably young age. In addition, polychaetes are not very mobile; active distribution of species is therefore very slow. Distribution by larval dispersal, in contrast, is dependent on ocean currents. A distribution originating from the deep Southern Ocean should be traceable by species records along large ocean currents, such as the Humboldt Current or the Antarctic bottom water. In contrast a possible distribution from the Southern Ocean northwards into more temperate waters can be recognized for some species. Sphaerodoropsis parva is supposedly invading the South Pacific via the Humboldt Current. Also a distribution along the west coast of Africa into the Angola basin can be seen. Braniella palpata is also recorded from sites along the Humboldt Current. The opheliid genus Ammotrypanella is presumably of Antarctic origin as well. Although A. arctica is reported also in the Northern Atlantic, the additional three species newly described for that genus are only known for the Southern Ocean until now. Records from the Pacific or Indic sector of Antarctica are not known for A. arctica. It is assumed that the species originates from the Southern Ocean and reached into the Northern Atlantic from there. Evidence for local radiation events is found in the families Syllidae (Sphaerosyllis), Opheliidae (Ophelina), Terebellidae (Pista), Scalibregmatidae (Oligobregma), and Sphaerodoridae (Sphaerodoropsis). The presented results predict that the deep Southern Ocean polychaete fauna is composed of relict species, species submerging from the Antarctic shelf, endemics that evolved during local radiation events, and species secondarily invading the deep sea from the Atlantic, Pacific, and Indic oceans. Additionally, an ongoing dispersal of deep-

166 DISCUSSION 157 sea species into northern deep-sea basins takes place, supported by currents and water masses such as the Humboldt Current and the Antarctic deep water. Based on the analysis of the global distribution patterns longitudinal gradients are not apparent within the Southern Ocean. Although local differences in species composition exist, a general pattern for the origin of species is not seen. The eastern Weddell Sea stations do not contain more Atlantic species while the stations of the Antarctic Peninsula are not apparently more related to the Pacific. However, during this study only a low number of stations were analyzed. The distances between stations were low in comparison to the size of the Southern Ocean. A sampling of the Pacific sector of the Southern Ocean might result in a more differentiated biogeographic picture.

167 SUMMARY Summary In course of this study the Polychaeta of the Antarctic deep sea have been analyzed. The sample material originated from the expeditions ANDEEP I-III to the Atlantic sector of the Southern Ocean in early spring 2002 and Samples were taken with an epibenthic sledge constructed at the Ruhr-University of Bochum. Analyses of biodiversity and community structure of the Polychaeta were carried out with the program PRIMER v In addition, the global distribution patterns of named species were reconstructed to gain insight into the possible origin of the Antarctic deep-sea benthos. In the samples 14,176 individuals of 47 families were found. Thirteen families were identified to species level, 155 species were distinguished. A percentage of 30 % of species were new to science indicating an undersampling of the Antarctic deep sea. During this study 18 species were described, three descriptions have already been published. Additionally, identification keys for all species found were constructed. Calculations of species richness (Margalef s Index) and diversity (Shannon Index and Pielou s Evenness) indicate high polychaete diversities in the Antarctic deep sea compared to deep-sea basins world wide. Within the sampling area the central Weddell Sea is characterized by the lowest diversity. Possible explanation is a lack of influences of faunal elements from adjacent deep-sea basins in comparison to the Drake Passage and the Antarctic Peninsula (possible Pacific influences), as well as the eastern Weddell Sea (possible Atlantic influences). Similarity analyses result in one main cluster that only presents minor differences between sampling areas. Within this cluster evidence for an east-west gradient in polychaete composition is given. On a regional scale the sampled sector of the Southern Ocean supposedly hosts a potentially homogenous polychaete community. Different influences of adjacent deep-sea basins, however, result in a longitudinal gradient between eastern and western stations. For local differences between stations sediment grain size is suggested as a factor of major influence. Depth seems to play a subordinated role. Vertical distribution patterns show a high percentage of eurybath species that are found on the upper continental slope as well as on the abyssal plains. Additionally, the presence of a classical deep-sea fauna becomes evident.

168 SUMMARY 159 The global distribution patterns of named species present distinct differences between the analyzed families. These might be based on reproduction strategies and habitat preferences. Based on distribution charts dispersal ways of polychaetes along ocean currents become apparent. The Humboldt Current supports the dispersal of species into the Pacific, the Antarctic bottom water that into the Atlantic. The found east-west gradient in species composition, as well as the finding of cosmopolitan species indicate that some polychaete species sampled originate from outside the Southern Ocean deep sea. The Antarctic deep sea is consequently not isolated, as known for the Antarctic shelf. Within the Southern Ocean there is evidence for submergence and emergence of polychaete species. Additionally, local radiation events originating from relict species are suggested.

169 ZUSAMMENFASSUNG Zusammenfassung Im Rahmen der vorliegenden Arbeit wurden die Polychaeta der antarktischen Tiefsee untersucht. Das analysierte Probenmaterial stammt von den Expeditionen ANDEEP I- III, welche im Winter und Frühjahr 2002 und 2005 im atlantischen Sektor des Südozeans durchgeführt wurden. Die Probennahme erfolgte mit einem an der Ruhr- Universität Bochum konstruierten Epibenthosschlitten. Analysen zur Biodiversität und Gemeinschaftsstruktur der Polychaeten wurden mit Hilfe des Programms PRIMER v durchgeführt. Zudem wurden die globalen Verbreitungsmuster benannter Arten rekonstruiert, um Rückschlüsse auf die Besiedlungsgeschichte der antarktischen Tiefsee zu erlangen. Die Proben umfassten Individuen aus 47 Familien. Hiervon wurden 13 Familien auf Artniveau bestimmt, 155 Arten wurden unterschieden. Der Anteil neuer Arten lag bei ca. 30 %, was für eine Unterbeprobung der antarktischen Tiefsee spricht. Im Laufe der vorliegenden Studie wurden 18 Arten neu beschrieben. Drei Neubeschreibungen wurden vorzeitig publiziert. Zudem wurden Bestimmungsschlüssel für alle in den Proben gefundenen Arten erstellt. Die Berechnung des Artenreichtums (Margalef s Index) und der Diversität (Shannon Index und Pielou s Evenness) weisen auf eine hohe Polychaetendiversität der antarktischen Tiefsee im Vergleich zu Tiefseebecken weltweit hin. Innerhalb des beprobten Areals ist das zentrale Weddell Meer durch die geringste Diversität charakterisiert. Eine mögliche Erklärung bietet der fehlender Einfluss von Faunenelementen aus benachbarten Tiefseebecken verglichen mit der Drake Passage und der Antarktischen Halbinsel (potentiell pazifische Einflüsse), sowie dem östlichen Weddell Meer (potentiell atlantische Einflüsse). Die Ähnlichkeitsanalysen resultieren in einem großen Cluster, der nur geringe Unterscheide zwischen den Regionen aufzeigt. Innerhalb des Clusters gibt es Hinweise auf einen Ost-West-Gradienten in der Polychaetenzusammensetzung. Auf regionaler Ebene ist daher zu vermuten, dass der beprobte Sektor des Südozeans eine potentiell homogene Polychaetengemeinschaft beheimatet. Unterschiedliche Einflüsse angrenzender Tiefseebecken des Atlantiks und Pazifiks resultieren jedoch in einem longitudinalen Gradienten zwischen östlichen und westlichen Stationen. Für lokale

170 ZUSAMMENFASSUNG 161 Unterschiede zwischen Stationen konnte die Sedimentgröße der beprobten Flächen als mögliche Erklärung ausgemacht werden. Die Tiefe scheint für die Artenzusammensetzung der Polychaeten nur eine untergeordnete Rolle zu spielen. Die vertikalen Verbreitungsmuster weisen auf einen hohen Anteil eurybather Arten hin, die sowohl auf dem oberen Kontinentalabhang zu finden sind, als auch auf den Tiefseeebenen. Zudem ist die Existenz einer klassischen Tiefseefauna nachgewiesen. Die globalen Verbreitungsmuster benannter Arten zeigen starke Unterschiede zwischen den analysierten Familien auf, welche auf Unterschieden in der Reproduktionsstrategie und der Habitatspräferenz basieren könnten. Anhand der erstellten Verbreitungskarten konnten klare Verbreitungswege einzelnen Polychaetenarten entlang ozeanischer Strömungen nachvollzogen werden. Der Humboldtstrom dient vermutlich der Verbreitung von Arten in den Pazifik, das Antarktische Tiefenwasser der in den Atlantik. Sowohl der Ost-West-Gradient in der Artenzusammensetzung als auch der Fund vieler Kosmopoliten weisen darauf hin, dass einige Polychaeten ihren Ursprung außerhalb des Südozeans haben. Die antarktische Tiefsee ist demnach nachweislich nicht isoliert wie der antarktische Schelf. Innerhalb des Südozeans gibt es Hinweise auf Submergenz und Emergenz von Polychaetenarten. Des Weiteren werden lokale Radiationsereignisse ausgehend von Reliktarten vermutet.

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189 APPENDIX- FIGURES Appendix 7.1 Figures App.-Fig. 1: Basic classification of Articulata (A/Pwr analysis) after Rouse & Fauchald, 1997 A A I/II B AIII Pholoididae Sphaerodoridae Spionidae Opheliidae Scalibregmatidae Spionidae Hesionidae Syllidae Polynoidae Terebellidae App.-Fig. 2A-B: Most abundant families of ANDEEP I-III stations

190 APPENDIX- FIGURES 181 C st 41-3 D st Onuphidae M aldanidae Pholoididae Ampharetidae Sphaerodoridae Spionidae Sphaerodoridae Pholoididae M aldanidae Cirratulidae E st 46-7 F st Sphaerodoridae Pholoididae Opheliidae Lumbrineridae Cirrat ulidae Opheliidae Scalibregmatidae Spionidae Cirrat ulidae Hesionidae G st H st Polynoidae Scalibregmatidae Acrocirridae Hesionidae 1 Polynoidae Ampharetidae Scalibregmatidae Syllidae App.-Fig. 2C-H: Most abundant families of ANDEEP I-III stations

191 APPENDIX- FIGURES 182 I st J st Ampharet idae Hesionidae Opheliidae Scalibregmatidae Spionidae Spionidae Glyceridae Polynoidae Fauveliopsidae K st L st Pholoididae Spionidae Polynoidae Hesionidae Fauveliopsidae 76 Spionidae Lumbrineridae Scalibregmatidae Glyceridae Sphaerodoridae M st N st Spionidae Opheliidae Ampharet idae Fauveliopsidae Hesionidae Polynoidae Spionidae Fauveliopsidae Ampharet idae Hesionidae Flabelligeridae Paraonidae App.-Fig. 2I-N: Most abundant families of ANDEEP I-III stations

192 APPENDIX- FIGURES 183 O st 59-5 P st Spionidae Cirratulidae Opheliidae Paraonidae Glyceridae Hesionidae Nephtyidae Polynoidae Spionidae Syllidae Hesionidae Ampharetidae Q st 78-9 R st Spionidae Pholoididae Opheliidae Glyceridae Ampharetidae Glyceridae Spionidae Hesionidae Fauveliopsidae Polynoidae S st 81-8 T st Spionidae Ampharet idae Sphaerodoridae Paraonidae Cirrat ulidae 49 Polygordiidae Spionidae Glyceridae Polynoidae Cirrat ulidae App.-Fig. 2O-T: Most abundant families of ANDEEP I-III stations

193 APPENDIX- FIGURES 184 U st V st Polygordiidae Glyceridae Spionidae Cirrat ulidae Hesionidae Polynoidae Spionidae Polygordiidae Opheliidae Glyceridae Ampharetidae W st X st Spionidae Opheliidae Glyceridae Fauveliopsidae Hesionidae 49 Opheliidae Ampharet idae Onuphidae Scalibregmatidae Trichobranchidae Y 403 st Z 6 6 st Syllidae Hesionidae Terebellidae Polynoidae Sphaerodoridae Fauveliopsidae Spionidae Cirratulidae Onuphidae Ampharetidae Trichobranchidae App.-Fig. 2U-Z: Most abundant families of ANDEEP I-III stations

194 APPENDIX- FIGURES 185 AA st AB st Pholoididae Spionidae Opheliidae Lumbrineridae Ampharetidae Spionidae Paraonidae Hesionidae Sternaspididae Syllidae AC st AD st Cirrat ulidae Hesionidae Nephtyidae Sphaerodoridae Spionidae Spionidae Pholoididae Onuphidae Opheliidae Syllidae AE 5 st Opheliidae Flabelligeridae Ampharetidae Sigalionidae Glyceridae Spionidae App.-Fig. 2AA-AE: Most abundant families of ANDEEP I-III stations

195 APPENDIX- FIGURES 186 App.-Fig. 3: Schematic figures for identifiction of species

196 APPENDIX- FIGURES 187 App.-Fig. 4: Schematic figures for identifiction of species

197 APPENDIX- FIGURES 188 A Typosyllis variegata Typosyllis cf. hyalina Trichobranchidae sp. 2 Trichobranchidae sp. 1 Travisia kerguelensis Travisia cf. lithophila Thelepodinae sp. 1 Thelepides venustus Thelepides koehleri Terebellides stroemii Terebellidae sp. 4 Terebellidae sp. 3 Terebellidae sp. 2 Terebellidae sp. 1 Syllides articulosus Streblosoma variouncinatum Sphaerosyllis lateropapillata Sphaerosyllis joinvillensis Sphaerosyllis antarctica Sphaerodoropsis maculata sp.n. Sphaerodoropsis distincta sp.n. Sphaerodoropsis simplex sp.n. Sphaerodoropsis polypapillata Sphaerodoropsis parva Sosanopsis sp. 1 Sosanopsis kerguelensis Sclerocheilus cf. antarcticus Scalibregma inflatum Samytha sp. 1 Pseudoscalibregma ursapium Pseudoscalibregma papilia sp.n. Pseudoscalibregma bransfieldium Proclea cf. graffii Proceraea cf. mclearanus Polycirrus sp. 2 Polycirrus sp. 1 Polycirrus insignis Polycirrus cf. antarcticus Pista spinifera Pista cristata Pista corrientis Pionosyllis sp. 1 Pionosyllis epipharynx Pionosyllis comosa Pionosyllis cf. maxima Phyllocomus crocea Phisidia sp. 1BH Phisidia rubrolineata Phalacrostemma elegans Parasyllidea delicata sp.n. Ophiodromus comatus Ophiodromus calligocervix sp.n. Ophelina sp. 5 Ophelina sp. 4 Ophelina sp. 3 Ophelina setigera Ophelina scaphigera Ophelina robusta sp.n. Ophelina nematoides Ophelina gymnopyge Ophelina breviata Ophelina ammotrypanella sp.n. Oligobregma sp. 1 Oligobregma quadrispinosa Oligobregma pseudocollare Oligobregma notiale Oligobregma hartmanae Oligobregma collare Oligobregma blakei Octobranchus antarcticus Nereis eugeniae Neosabellides elongatus Muggoides sp. 1BH Muggoides cf. cinctus Mugga sp. 1BH Micropodarke cylindripalpata sp.n. Micronephtys sp. 1 Melinna cristata

198 APPENDIX- FIGURES 189 B Lysilla sp. 1 BH Leaena wandelensis Leaena sp. 4 Leaena pseudobranchia Leaena collaris Leaena cf. collaris Leaena arenilega Leaena antarctica Laphania cf. boecki Kesun abyssorum Kefersteinia fauveli Hyboscolex equatorialis Hesionidae sp. 1 Hauchiella tribullata Gyptis incompta Grubianella sp. 1 Grubianella antarctica Goniada maculata Glyphanostomum scotiarum Glycera kerguelensis Exogone sp. 7 Exogone sp. 6 Exogone sp. 5 Exogone sp. 2 BH Exogone minuscula Exogone heterosetosa Eusamythella sp. 1 Eupistella sp. 1 Eupistella grubei Ephesiella hartmanae sp.n. Ephesiella antarctica Clavodorum antarcticum cf. Thelepus cincinnatus cf. Thelepides venustus cf. Terebellides sp. 1BH cf. Nicon cf. Neosabellides cf. Autolytus simplex stolon cf. Amphisamytha Ceratocephale sp. 1BH Braniella palpata Brania sp. 1 BH Bathyglycinde sp. 2 Bathyglycinde sp. 1 BH Axiokebuita minuta Axiokebuita millsii Autolytus gibber Asclerocheilus ashworthi Anobothrus pseudoampharete sp.n. Anobothrus gracilis Anobothrella sp. 1 Anobothrella antarctica Amythas membranifera Amphiduros sp. 1 Amphiduros serratus sp.n. Amphicteis sp. 3 Amphicteis sp. 2 Amphicteis sp. 1 Amphicteis juvenile Amphicteis gunneri Ampharetidae sp. 7 Ampharetidae sp. 6 Ampharetidae sp. 5 Ampharetidae sp. 4 Ampharetidae sp. 3 Ampharetidae sp. 3 Ampharetidae sp. 2 Ampharetidae sp. 1 Ampharete kerguelensis Ammotrypanella mcintoshi sp.n. Ammotrypanella princessa sp.n. Ammotrypanella cirrosa sp.n. Ammotrypanella arctica Amage sculpta Aglaophamus trissophyllus Aglaophamus paramalmgreni aff. Hesionides App.-Fig. 5: Vertical distribution ranges for species found during ANDEEP I-III, A- species M-Z, B- species A-L

199 APPENDIX- FIGURES 190 App.-Fig. 6: Global distribution of 84 named species found during the expeditions ANDEEP I-III (record list see chapter 2.4.2)

200 APPENDIX- FIGURES 191 A Ampharetidae B Opheliidae C Scalibregmatidae D Sphaerodoridae E Syllidae F Terebellidae LR SU 4 11 SA SP SH C App.-Fig. 7A-F: Global distribution of southern ocean deep-sea polychaete species collected during the expeditions ANDEEP I-III (total numbers; C- cosmopolitan, SH- southern hemisphere, SP- South Pacific, SA- South Atlantic, SU- subantarctic, LR- locally restricted within the Southern Ocean)

201 APPENDIX- FIGURES 192 App.-Fig. 8: Global records of the Ampharetidae- Anobothrus gracilis, Station App.-Fig. 9: Global records of the Glyceridae

202 APPENDIX- FIGURES 193 App.-Fig. 10: Global records of the Goniadidae App.-Fig. 11: Global records of the Hesionidae

203 APPENDIX- FIGURES 194 App.-Fig. 12: Global records of the Nereididae App.-Fig. 13: Global records of the Nephtyidae

204 APPENDIX- FIGURES 195 App.-Fig. 14: Global records of the Opheliidae- Ammotrypanella arctica App.-Fig. 15: Global records of the Sabellariidae

205 APPENDIX- FIGURES 196 App.-Fig. 16: Global records of the Scalibregmatidae- Axiokebuita millsi, A. minuta, Scalibregma inflatum App.-Fig. 17: Global records of the Sphaerodoridae- Ephesiella antarctica, Clavodorum antarcticum