Out of the doldrums: Campylaspis stephenseni Just, 1970 revived (Crustacea, Cumacea, Nannastacidae)

Transcription

1 campylaspis stephenseni r e v i v e d Out of the doldrums: Campylaspis stephenseni Just, 1970 revived (Crustacea, Cumacea, Nannastacidae) 45 JEAN JUST Steenstrupia Just, J. Out of the doldrums: Campylaspis stephenseni Just, 1970 revived (Crustacea, Cumacea, Nannastacidae). Steenstrupia 32 (1): Copenhagen, Denmark. February ISSN Based on type and new material, Campylaspis stephenseni Just, 1970 and C. intermedia Hansen, 1920 are illustrated, and a previously proposed synonymy of the former under the latter name is rejected. The distribution of the two species is discussed. Keywords: Campylaspis stephenseni, C. intermedia, identification, distribution Jean Just, Zoological Museum, Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark. jean-just@mail.dk INTRODUCTION Species of the nannastacid genus Campylaspis G.O. Sars, with approximately 130 species, are found throughout the world from shallow water to abyssal depths (Watling, 2005), but they are scarce in arctic waters. Up until 1970 only four specimens had been reported from East Greenland: Campylaspis intermedia Hansen, 1920 by Zimmer (1934, Dusénfjord, Franz Joseph Fjord area, m, -1.2 C, 2 specimens; material not seen by me) and Campylaspis sp., (Stephensen, 1943, Hurry Inlet, Scoresby Sund area, 2 specimens). Just (1970) described a new species, Campylaspis stephenseni, from Jørgen Brønlund Fjord, Northeast Greenland. At the same time Stephensen s specimens were re-examined. One was found to belong to Campylaspis rubicundum G.O. Sars, a species also reported from Jørgen Brønlund Fjord (Just, 1970). The second specimen belonged to Campylaspis stephenseni. Muradian-Ciamician (1980) reported Campylaspis intermedia from off Beaufort, North Carolina, eastern U.S.A at 344 and 692 m depth. In a very brief and ambiguous note Campylaspis stephenseni Just was, without any explanation, placed in synonymy of Campylaspis intermedia Hansen. In several of the proliferating web based regional check lists the names Campylaspis stephenseni and C. intermedia are used indiscriminately, presumably as a result of Muradian-Ciamician s (1980) synonymisation. The purpose of this note, therefore, is to document, in the simplest way, the differences between Campylaspis intermedia and C. stephenseni, and confirm the latter as a distinctive arctic species so far known from around Greenland only. The distribution of the two species is discussed in a separate section. IDENTIFICATION In Fig.1 Campylaspis stephenseni is documented from north eastern, central eastern, southernmost, and north western Greenland. Apart from the paratype female (Fig. 1B) all specimens are previously unreported, (the specimens are kept in the Zoological Museum, Copenhagen). Collecting data are as follows: Fig. 1A, Jørgen Brønlund Fjord, Peary Land, Northeast Greenland, W of Mundingsholm, 52 m, grey-brown clay, detritus-dredge, Just & Steenstrupia 32 (1):

2 46 j. j u s t Fig. 1. Campylaspis stephenseni Just, A. Subadult male, Jørgen Brønlund Fjord, lateral and dorsal view. B. Female, paratype, Hurry Inlet, East Greenland. C. Subadult male, Kap Seddon, Northwest Greenland. D. Adult male, Kap Farvel, South Greenland, lateral and dorsal views. Scale = 2 mm. Schiøtte, st. PL16, 14 August Fig. 1B (paratype), Hurry Inlet, East Greenland, the mouth, 57 m, sandy clay, 30 June 1933 Godthaab st. 43. Fig. 1C, Bay at Kap Seddon, Melville Bay, Northwest Greenland, 75º20.8 N 58º38.6 W, m, clay, some sand and gravel, detritusdredge, H. & J. Just, RNV Ingolf st. 5, 4 August

3 campylaspis stephenseni r e v i v e d 47 Fig. 2. Campylaspis intermedia Hansen, Syntypes. F. Female, lateral and dorsal views. M. Subadult male, lateral view. Scale = 2 mm Fig. 1D, Nua, Kap Farvel area, South Greenland, 59º53.5 N 44º22.3 W, 140 m, stones, gravel, polychaete tubes, triangular dredge, J. Just, Kap Farvel Expedition st. 88, 9 August The illustrations document a consistent pattern of dorsal and lateral carapace sculpture throughout the known distribution of the species. In females and subadult males there are four dorsolateral keels, (including the dorsoposterior ridge which runs onto the carapace laterally), which merge two-and-two laterally to continue as two single, parallel keels to the ventral front margin. The keels are beset with irregularly spaced rounded knobs. Dorsally, in front of the keels, there are two larger lateral knobs and more medially four smaller knobs in a square. Posteriorly on the dorsal side there are another four smaller knobs arranged in a similar square. The pattern is slightly modified in adult and near adult males (Fig. 1D, and Just 1970, fig. 9a of holotype): the entire carapace is moderately elongate and less deep. The upper posterior branch of the upper lateral keel system is more weakly developed than in the other specimens shown and does not quite connect with the main branch. Younger males (see Fig. 1A) are similar to females. Fig.2 shows a female and a subadult male of Hansen s syntypes of Campylaspis intermedia (material in the Zoological Museum, Natural

4 48 j. j u s t Fig. 3. Records of Campylaspis stephenseni (circles, T = type locality, holotype) and C. intermedia (squares, S = type localities, syntypes). Black: material seen by the author in preparing this study; open: material not seen. 1, Zimmer 1934; 2, Jones 1984; 3, Vassilenko & Brandt 1996; 4, Gerken & Watling 1999;?, Lomakina 1958.

5 campylaspis stephenseni r e v i v e d 49 History Museum of Denmark, Copenhagen). The lower lateral keel system is similar to C. stephenseni, but the upper keel does not have a two-pronged posterior part. In addition, there is a vertical, broad keel anteriorly between the upper and lower lateral keels, which is not found in C. stephenseni. The carapace space between the upper and lower keels and behind the vertical keel is broader and deeper than in C. stephenseni. Campylaspis intermedia has the same large dorsolateral knobs but lacks the corresponding four smaller anterior knobs in a square. DISTRIBUTION In addition to the records listed in the Introduction and Identification sections above, the two species in question have been reported as follows: Jones (1984; Fig. 3, 2) reported Campylaspis intermedia from the southern Bay of Biscay. Vassilenko and Brandt (1996; Fig. 3, 3) and Brandt (1997; Fig. 3, 3) listed Campylaspis intermedia ( m depth) and C. stephenseni ( m) from several stations along northeast Greenland from 75 N to 81 N. Gerken and Watling (1999; Fig. 3, 4) reported Campylaspis intermedia (= C. stephenseni Just, 1970) from 15 BioFar stations around the Faroe Islands ( m). Lomakina (1958, Fig. 3;?) quotes Zimmer (1946, Sedov Reports, in Russian) as reporting Campylaspis intermedia? from Franz Joseph Land and Novaja Zemlya. I have not seen Zimmer s report, but have indicated the possible occurrence in Fig. 3 (?). The depth range of Campylaspis stephenseni as presently known appears to be between 25 and 500 meters, with the species occurring in arctic waters of less than about 2 C. Until the various materials of Campylaspis intermedia listed above have been re-assessed it is not possible to ascertain the depth range and true occurrence of that species, but it seems likely to be present further south and reaching greater depths in the North Atlantic than the former species. DISCUSSION Based on the differences in carapace sculpture the two species are easily separated. Consequently Campylaspis stephenseni Just is removed from synonymy with C. intermedia Hansen and re-instated as a valid species. One question remains: what did Muradian- Ciamician (1980) have to hand when reporting Campylaspis intermedia from off Beaufort, eastern U.S.A.? Muradian-Ciamician (1980: 75; no illustrations provided; no indication that the type materials were examined) writes Although mostly preadult, our specimens certainly belong to this species. As to the whole picture, the one drawn by Just (1970) is more consistent with reality: in Hansen s drawing, the tubercles figured in square section lead to errors [my italics]. Comparison of my illustrations of syntypes of Campylaspis intermedia with Hansen s illustrations (1920, plate III, fig.6) shows that Hansen s rather dark figures, are resonably correct and should not easily lead to error in identification. Hence the Beaufort specimens cannot be Campylaspis intermedia. The reference to Hansen s drawing in square section is uninterpretable. Hansen illustrated a subadult female in lateral and dorsal views, as in my Fig.2A. As to the illustration by Just (1970, fig.9 A) being more consistent with reality, this subjective statement appears to convey only that the Beaufort specimens looked more like Campylaspis stephenseni than C. intermedia. Did Muradian-Ciamician have Campylaspis stephenseni before him? The specimens were collected at 344 and 692 meters depth, so it is marginally possible that this high arctic species could be found on the mid-slope of the western Atlantic. With the difficulties in identification encountered by Muradian-Ciamician, leading to an unjustified synonymization, it is more likely, however, that the Beaufort specimens represent an undescribed species. It is hoped that this short note may provide help in resolving the issue through a re-evaluation of Muradian-Ciamician s material.

6 50 j. j u s t REFERENCES Brandt, A The species composition of the peracarid fauna (Crustacea, Malacostraca) of the Northeast Water Polynya (Greenland). Meddelelser om Grønland, Bioscience 44: Brandt, A Biodiversity of peracarid crustaceans (Malacostraca) from the shelf down to the deep Arctic Ocean. Biodiversity and Conservation 6: Gerken, S. & L. Watling Cumacea (Crustacea) of the Faroe Island Region. Fróðskaparrit 47: Hansen, H. J Crustacea Malacostraca IV. The order Cumacea. The Danish Ingolf Expedition III (6): Jones, N. S The family Nannastacidae (Crustacea: Cumacea) from the deep Atlantic. Bulletin of the British Museum (Natural History), Zoology Series, 46: Just, J Cumacea from Jørgen Brønlund Fjord, North Greenland. Meddelelser om Grønland 184 (8): Lomakina, N. B Cumacea of the seas of SSSR. Fauna SSSR 66: (In Russian) Muradian-Ciamician, Z On some species belonging to the genus Campylaspis (Cumacea, Nannastacidae) from the collections of the Natural History Museum Grigore Antipa. Traveaux du Muséum d Histoire naturelle Grigore Antipa 21: Stephensen, K Leptostraca, Mysidacea, Cumacea, Tanaidacea, Isopoda, and Euphausiacea. Meddelelser om Grønland 121 (10): Vassilenko, S. V. and Brandt, A Composition and biogeographic structure of the cumacean fauna of the Northeast Water Polynya, Greenland (Crustacea Peracarida Cumacea). Arthropoda Selecta 5 (3/4): Watling, L Cumacea World Database. Consulted Zimmer, C Die Cumaceen der norwegischen Expeditionen nach Ost-Grönland 1929, 1930, 1931 und Zoological Results of the Norwegian Expedition to East Greenland III. Skrifter om Svalbard og Ishavet 61: