TOWARDS PHYLOGENY AND ZOOGOGRAPHY OF THE GENUS RHEOTANYTARSUS THIENEMANN ET BAUSE, 1913 (DIPTERA: CHIRONOMIDAE)

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1 OLE A. SÆTHER & ROSINA A. K. KYEREMATEN Museum of Zoology, University of Bergen, Norway & Department of Zoology, University of Ghana, Accra, Ghana TOWARDS PHYLOGENY AND ZOOGOGRAPHY OF THE GENUS RHEOTANYTARSUS THIENEMANN ET BAUSE, 1913 (DIPTERA: CHIRONOMIDAE) Sæther, Ole A. & R. A. K. Kyerematen Towards phylogeny and zoogeography of the genus Rheotanytarsus Thienemann et Bause, 1913 (Diptera: Chironomidae. Tijdschrift voor Entomologie 144: , figs , tables 1-6. [ISSN ]. Published 1 June Additions and corrections to the generic diagnosis of the genus Rheotanytarsus Thienemann et Bause is given. A list of all described species is given. Tanytarsus apenninicus Rossaro (1993: 233) is a junior synonym of Rheotanytarsus nigricauda Fittkau (1960: 397). R. kwangungensis Ree (1989: 211) probably is a junior synonym of Tanytarsus thermae Tokunaga (1940: 304), but not formally synonymized. The genus can be divided into four groups based on pupa alone, the ceratophylli, pellucidus, nigricauda, and curtistylus groups. The first three appear to be clearly monophyletic, while the curtistylus group is not. In order to determine the phylogeny of the genus all previously described species were re-examined from specimens available or from the literature. Different parsimony analyses were performed. The preferred tree using constraints based on the pupal types and species pairs repeatedly found in parsimony analyses yielded 15 groups: the aestuarius group consisting of 2 species only, the acerbus group with 6 species, the muscicola group with 13 species, the monotypic pentapoda group, the pellucidus group with 9 species, the sessilipersonatus group with 3 species, the globosus group with 5 species, the ororus group with 7 species, the aquilus group with 6 species, the thermae group with 5 species, the trivittatus group with 7 species, the curtistylus group with 3 species, the exiguus group with 6 species, the orientalis group with 4 species, and the guineensis group with 17 species. The preferred tree has the aestuarius group as the sister group of the remaining species with the following sequence (aestuarius gr. ((acerbus gr., muscicola gr.) (pentapoda gr. ((pellucidus gr. (sessilipersonatus gr. ((globosus gr., ororus gr.) (aquilus gr. (thermae gr., trivittatus gr.))))) (curtistylus gr. ((exiguus gr., orientalis gr.) guineensis gr.)))))). Geographic coevolutionary analyses were performed using Brooks Parsimony Analysis (BPA). Based on the area cladogram ancestral area analyses using the methods of Bremer (1992) and a modification of Ronquist (1994) and Michelsen (1994) counting terminal shifts only were also done. The genus Rheotanytarsus likely originated in Pangea prior to the final split between Africa and South America, but much later than the first break-up of the continents in the south. The ancestral area probably included Northeast Africa and South Asia. The genus shows a warm / eurythermic vicariant Gondwanan pattern with multiple sister group relationships between the South Asia subregion and the Afrotropical regions. The East Asia - North America linkage is likely of post-miocene origin. African - West Palaearctic and South Asian - West Palaearctic vicariance are found in several groups. The evidence for West African - Brazilian vicariance is present, but very limited. Correspondence: O. A. Sæther, Museum of Zoology, Department of Zoology, University of Bergen, N-5007 Bergen, Norway. ole.sather@zmb.uib.no Key words: Rheotanytarsus, Chironomidae, Diptera, species list, phylogeny, zoogeography. The larvae of Rheotanytarsus are rheobiontic, filter feeding using nets suspended between arms at the anterior end of their characteristic cases (Walshe 1950, 1951, Thienemann 1954, Scott 1967, Pinder & Reiss 1983, Berg 1995, Kyerematen 1999). The houses may be made of diatoms glued together by secretions and attached to the substrate for their full length, as in some Oriental and Nearctic species (Thienemann 1954, figs. 14, 31); or, more usually, made out of sand grains or mud particles. Characteristically, there are arm-like apical extensions between which silk strands are suspended to catch particles of suspended detritus, which are utilised both as food and for case building. Occasionally, these arms are rudimentary or lacking, normally there are from 1-6 such arms (Thienemann 1954). The arms normally are about half as long as 73

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3 SÆTHER & KYEREMATEN: Rheotanytarsus phylogeny the houses, but may reach ¾ the length or even the full length of the houses (fig. 22). Kullberg (1988) describes the elaborate mechanism of tube and net building in R. muscicola. Most larvae live in moderately fast to moderately slow flowing rivers and streams. Although Cranston (1995) mentions that all Rheotanytarsus live in flowing waters R. ceratophylli larvae live in temporary stagnant waters (Dejoux 1973), and the distribution of some species indicate that some larvae perhaps live in the marine intertidal zone. According to Tokeshi (1995) larvae of Rheotanytarsus may be phoretic on a number of other aquatic invertebrates including odonates, mayflies, caddis flies, megalopterans and gastropods. The genus is particularly plentiful both in numbers of species and in individuals in tropical rain forests (Cranston 1997, Kyerematen 1996, 1999, Kyerematen & Andersen 2001a, b, Kyerematen et al. 2000a, 2000b). Up to now 94 species have been described, including 38 recently described species, from all zoogeographical regions except the Antarctic. According to Sublette & Sublette as personal communication in Simpson & Bode (1980) there are approximately 15 species of Rheotanytarsus in eastern North America. The European species was revised by Lehmann (1970), the Australian by Cranston (1997), while a number of Japanese species described by Sasa and colleagues are listed in Sasa & Kikuchi (1995). The Afrotropical species were recently revised by Kyerematen & Sæther (2000); the Oriental by Kyerematen et al. (2000a); and the Neotropical by Kyerematen & Andersen (2001a, b). Dr. J. E. Sublette is presently revising the Nearctic species. MORPHOLOGY AND TERMINOLOGY Morphological nomenclature follows Sæther (1977, 1980) with the additions mentioned in Sæther (1990a, b). The broad flattened setae of the pupal exuviae are called taenia(e) in accordance with Langton (1994). MATERIAL Most available material from the Afrotropical, Oriental and Neotropical regions have been examined except when previous descriptions are essentially complete (Kyerematen & Sæther 2000, Kyerematen & Andersen 2001, Kyerematen, et al. 2000a, b). Additional material from the Palaearctic, Nearctic, Neotropical and Australian regions available in the collection of the Museum of Zoology, University of Bergen (ZMBN), or borrowed from Zoologisches Staatssammlung, Munich, Germany (ZSM); the Canadian National Collection, Ottawa, Ontario, Canada (CNC); Instituto de Biologia, Universidad Nacional Autónomia de Mexico, Mexico City, Mexico (IBUNAM); The Academy of Natural Sciences, Pennsylvania, Philadelphia, USA (ANSP); Cornell University Insect Collection, New York State, Cornell, USA (CUC); the collection of Dr. J. E. Sublette, Tucson, Arizona, USA (JES); and Division of Entomology, CSIRO, Canberra, Australia (CSIRO), were also examined. Examined Palaearctic, Nearctic and Australian species not included in the above-mentioned papers include: R. akrinus (Roback), R. muscicola (Thienemann), R. nigricauda Fittkau, R. pentapoda Kieffer, R. photophilus Goetghebuer, R. ringei Lehmann and R. rivulophilus Kawai et Sasa. Rheotanytarsus Thienemann et Bause Rheotanytarsus Thienemann et Bause in Bause 1913: 120. Type species: Tanytarsus pentapoda Kieffer, 1909, by subsequent designation of Goetghebuer (1954: 132). Syntanytarsus (Rheotanytarsus Thienemann et Bause), in Bause 1913: 120. Tanytarsus (Rheotanytarsus) auct. Rheotanytarsus Thienemann et Bause, Fittkau 1960: 397. Diagnostic characters The imagines are separable from other Tanytarsini by having bare eyes with strong dorsomedial extension; no frontal tubercles; maxillary palp 5-segmented, with 2 short blunt-tipped sensilla clavata at apex of third palpomere; antepronotum strongly reduced; no scutal tubercle; 1 prealar seta; costa ending distinctly distal to apex of M3+4; mid and hind tibiae with separate combs; and pulvilli absent or, in a few tropical species, vestigial. Most male imagines are easily recognised by the characteristic shape of the gonostylus, which is abruptly narrowed distally. The shape of the anal point is also sufficient to distinguish them from the closely related genera of Tanytarsini (e.g. Paratanytarsus Thienemann et Bause). The fusion of the subulate or foliate setae of the median volsellae into plate-like structure is also characteristic of most members of the genus. The female imagines have gonapophysis VIII clearly divided into ventrolateral and dorsomesal lobes; apodeme lobe distinct, and apparently with weak microtrichiae; floor under vagina small to moderately sized; and notum more than 2.5 times as long as seminal capsules. Figs Rheotanytarsus spp., male and female imagines R. pantanalensis Kyerematen et Andersen, male imago. 1, head; 2, thorax; 3, wing; 4, 5, hypopygium, dorsal and ventral view; 6, superior volsella; 7, 8, median volsella R. nigricauda Fittkau, female imago, genitalia. 9, 10, ventral and dorsal view; 11, apodeme lobe of gonapophysis IX; 12, ventrolateral lobe of gonapophysis VIII; 13, dorsomesal lobe of gonapophysis VIII. 75

4 TIJDSCHRIFT VOOR ENTOMOLOGIE, VOLUME 144, 2001 The pupae can be separated from those of other genera by the presence of a single caudolateral spur or at most six spurs on segment VIII with the exception of a few species that have up to 10 spurs, and the spines on the tergites arranged in paired anterior point patches. All other genera with similar arrangement of spines have relatively complex caudolateral combs, usually with many spines and additional dorsal teeth. The larvae construct a case or house; the case bears a few to at most six arm-like extensions at the unattached end (fig. 22). The larvae can also be separated from those of other genera by the pecten epipharyngis, which is a single, broad, distally serrated plate, which may however be deeply divided into 3 lobes; combined with a bifid premandible and Lauterborn organs on short pedestals. Diagnosis As in Pinder & Reiss (1983, 1986) and Cranston et al. (1989) with the following additions: Imagines (figs. 1-13, 23-73): Third palpomere bearing 2 short blunt-tipped sensilla clavata. Tentorium without microtrichiae. Temporals consisting of inner and outer verticals and postorbitals. Preepisternum and anepisternum bare. Brachiolum with 1 seta. None to few sensilla chaetica on distal part of tarsus 1 of mid leg. Pulvilli absent or vestigial (in a few tropical species). Anal tergite bands when fused sometimes horizontal. Anal point short to long. Superior volsella (figs. 6, 45-53) oval to rounded in shape or of variable shape, sometimes with posterior margin knob-like. Digitus vestigial to well developed. Inferior volsella roughly cylindrical and slightly expanded distally, sometimes sharply pointed and recurved at apex. Median volsella with subulate or foliate setae often partially or fully fused to form plate-like structure with or without apical points. Gonostylus sometimes hooked at apex. Pupa (figs ): Small to medium sized pupa. Frontal setae when present slender and elongate. Frontal apotome smooth, extremely tuberculous apically or over most of apotome. Thoracic horn usually short, heavily sclerotized or hyaline, with points on distal half to entire length, occasionally with median sharp bend. 3 precorneals, 2 broadly and 1 narrowly taeniate. Spines on tergites II-IV, II-V or II- VI with circular spine patches or bands of dark spines. Abdomen sometimes with extensive shagreen. Tergite II with posterior shagreen. Hook row occupying 1 /7-⅔ width of segment. Segment VIII with 3-6 curved thorn-like spurs. Segment II-V with 2-3 L-setae, VI with 3-4, VII with 4 and VIII with 3-5 setae, all hairlike on II and III, IV with 1-2 hair-like and 1-2 taeniate and all taeniate on V-VIII, or all hair-like on II- VII(VIII). In one Afrotropical and Palaearctic species fringe of anal lobe completely absent. Anal lobe with or without hair-like or taeniate dorsal seta. Larva: Small to medium sized pale coloured larvae. Procercus short, bearing medium to long anal setae. Described species Up to now 94 valid species including the ones described in Kyerematen & Sæther (2000), Kyerematen et al. (2000a, b) and Kyerematen & Andersen (2001) have been described from all zoogeographical regions: West Palaearctic species: curtistylus (Goetghebuer, 1921: 121, as Tanytarsus). Europe, Lebanon (?Thailand). illiesi Siebert, 1979: 165. Germany. montanus Lehmann, 1979: 62. Italy (D. R. Congo, South Africa). muscicola Thienemann, 1929: 113. Europe, Algeria, Morocco (China, Mongolia). pellucidus (Walker, 1848: 21, as Chironomus), nec R. pellucidus Chaudhuri et Datta in Chaudhuri et al.1994: 156 (= Micropsectra pellucidus), Europe, North Africa Mongolia, Canada (Ontario), USA). nigricauda Fittkau, 1960: 397, syn. Tanytarsus apenninicus Rossaro, 1993: 233, syn n. Europe (F. Reiss pers. comm.). pentapoda Kieffer, 1909: 51. Europe. photophilus Goetghebuer, 1921:115. Europe. procerus Reiss 1991: 50. Morocco. reissi Lehmann, 1970: 368. Europe (Thailand). rhenanus Klink, 1983: 136. Europe. ringei Lehmann, 1970: 370. Europe, Morocco. rioensis Langton et Armitage, 1995:11. Canary Islands (South Africa). samaki Lehmann, 1979: 65. Lebanon (D. R. Congo, Ethiopia). East Asian species: acerbus (Johannsen, 1932: 547, as Tanytarsus). China (India, Indonesia (Sumatra)). aestuarius (Tokunaga, 1938: 360, as Tanytarsus), syn. tumidus Chaudhuri & Datta, in Chaudhuri et al.1994: 153; Kyerematen et al. 2000a: 229. Japan, China (India). curtistylus (Goetghebuer, 1921: 121, as Tanytarsus).?Thailand (Europe, Lebanon). dogoensis Ree et Kim, 1988: 21. Korea. fluminis Kawai et Sasa, 1985: 20. Japan. kuramasimplex Sasa, 1989: 51, syn. kibunexpandus Sasa, 1989: 56, Japan. kyotoensis (Tokunaga, 1938: 345, as Tanytarsus), Japan. muscicola Thienemann, 1929: 113. China, Mongolia (Europe, Algeria, Morocco). parvicrinis (Tokunaga, 1938: 343, as Tanytarsus). Japan. pellucidus (Walker, 1848: 21, as Chironomus), nec R. pellucidus Chaudhuri et Datta in Chaudhuri et al.1994: 156 (= Micropsectra pellucidus), Mongolia (Europe, North Africa, Canada (Ontario), USA). reissi Lehmann, 1970: 368. Thailand (Europe). rivulophilus Kawai et Sasa, 1985: 21, syn. gayaensis Ree 1992: 135, Japan, S. Korea. tamaquartus Sasa, 1980: 16. Japan, China. tamaquintus Sasa, 1980: 18. Japan. tamasecundus Sasa, 1980: 13. Japan. 76

5 SÆTHER & KYEREMATEN: Rheotanytarsus phylogeny tamatertius Sasa, 1980: 14. Japan. thermae (Tokunaga, 1940: 304, as Tanytarsus). Probable synonym Rheotanytarsus kwangungensis Ree 1989: 211, Japan, S. Korea. Although the species not have been reexamined there is little doubt about the synonymy as the descriptions are relatively complete and both species are recorded from hot springs. However, since the species not have been re-examined a formal synonymizing should wait. yufualbus Sasa et Suzuki, 1991: 98. Japan. South Asian (Indo-Malaysian) species: acerbus (Johannsen, 1932: 547, as Tanytarsus). Indonesia (Sumatra), China, India. aestuarius (Tokunaga, 1938: 360, as Tanytarsus; syn R. tumidus Chaudhuri & Datta in Chaudhuri et al.1994: 153. India (Japan, China). additus (Johannsen, 1932: 548, as Tanytarsus). Indonesia (Java, Sumatra). adjectus (Johannsen, 1932: 547, as Tanytarsus). Indonesia (Java). amamiflavus Sasa, 1990: 123, Nansei Islands, Oriental Japan. beccus Kyerematen, Andersen et Sæther, 2000: 248. Thailand. curtistylus (Goetghebuer, 1921: 121, as Tanytarsus).?Thailand (Europe, Lebanon). falcatus Kyerematen, Andersen et Sæther, 2000: 252. Thailand. falcipedius Kyerematen, Andersen et Sæther, 2000: 241. Thailand. koraensis Kyerematen, Andersen et Sæther, 2000: 250. Thailand. kuantanensis Kyerematen, Andersen et Sæther, 2000: 237. Malaysia. madarihatensis Kyerematen, Andersen et Sæther, 2000: 255. Malaysia, India. minusculus Kyerematen in Kyerematen, Sæther & Andersen, 2000:168. Thailand. okisimplex Sasa, 1993: 130. Okinawa, Oriental Japan. orientalis Moubayed, 1989: 278, Thailand. oss Cranston 1997: 722. Thailand (Australia). pallidus Kyerematen, Andersen et Sæther, 2000: 249. Thailand. phaselus Kyerematen, in Kyerematen, Andersen et Sæther, 2000: 249. Malaysia. reissi Lehmann, 1970: 368.?Thailand (Europe). sessilipersonatus Kyerematen, Andersen et Sæther, 2000: 230. Thailand. soelii Kyerematen, Andersen et Sæther, 2000: 232. Thailand. tobaseptidecimus Kikuchi et Sasa, 1990: 317. Indonesia (Sumatra). thailandensis Moubayed, 1990: 29. Thailand. trivittatus Johannsen, 1932: 546. Indonesia (Sumatra) (Australia). verticillus Kyerematen, Andersen et Sæther, 2000: 240. Thailand. Australian species: barrengarryensis Cranston, 1997: 711. Australia. christinae Glover, 1973: 420. Australia. flabellatus Glover, 1973: 420. Australia. gloveri Cranston, 1997: 718. Australia. juliae Glover, 1973: 424. Australia. oss Cranston, 1997: 722. Australia (Thailand). petropholeter Cranston, 1997: 722. Australia. trivittatus Johannsen, 1932: 546. Australia (Indonesia (Sumatra)). underwoodi Glover, 1973: 425. Australia. Nearctic species: akrinus (Roback, 1960a: 1, as Calopsectra). USA (Kansas). exiguus (Johannsen, 1905: 294, as Tanytarsus). Canada, USA (Neotropical (St. Croix)). hamatus Sublette et Sasa, 1994: 52. USA (Arizona) (Guatemala). pellucidus (Walker, 1848: 21, as Chironomus). Canada (Ontario), USA (Europe, North Africa, Mongolia). Central American species: baculus Kyerematen et Andersen, 2001 a. Costa Rica. calakmulensis Kyerematen et Andersen, 2001 a. Mexico. contrerasi Andersen et Sæther in Kyerematen, Sæther et Andersen, 2000: 166. Mexico. exiguus (Johannsen, 1905: 294, as Tanytarsus). St. Croix (Nearctic). foliatus Kyerematen et Andersen 2001 a. Costa Rica, Mexico. guanacastensis Kyerematen et Andersen, 2001 a. Costa Rica. hamatus Sublette et Sasa, 1994: 52. Guatemala (USA). hanseni Kyerematen et Andersen, 2001 a. Mexico. kusii Kyerematen in Kyerematen & Andersen, 2001 a. Mexico. meridionalis (Johannsen, 1938: 222). Puerto Rico. nuamae Kyerematen in Kyerematen & Andersen, 2001 a. Mexico. ramirezae Kyerematen in Kyerematen & Andersen (2000). Mexico. scutulatus Kyerematen et Andersen, 2001 a. Costa Rica. subtilis Kyerematen et Andersen, 2001 a. Costa Rica. thunesi Kyerematen et Andersen, 2001 a. Costa Rica. South American species: globosus Reiss, 1972: 64. Chile, Argentina. lamellatus Reiss, 1972: 67. Chile. pantanalensis Kyerematen et Andersen, 2001 b. Brazil. pelus (Roback, 1960b: 105, as Calopsectra). Peru. Afrotropical species: abonae Kyerematen in Kyerematen et Sæther, 2000: 43. Tanzania. acuminatus Kyerematen et Sæther, 2000: 35. Tanzania angustus (Freeman 1955: 35). D. R. Congo, Tanzania, South Africa. aquilus Kyerematen et Sæther, 2000: 53. Ghana. atrius Kyerematen et Sæther, 2000: 59. Ghana. buculicaudus Kyerematen in Kyerematen, Sæther & Andersen, 2000:165. Ghana. bufemoratus Kyerematen et Sæther, 2000: 39. Uganda. ceratophylli (Dejoux, 1973: 66, as Tanytarsus). Chad, Sudan, Senegal, Ghana, Nigeria. digitatus Kyerematen et Sæther, 2000: 65. Ghana. fuscus (Freeman, 1954: 25, as Tanytarsus). South Africa. guineensis (Kieffer, 1918: 73, as Tanytarsus). Guinea, D. R. Congo, South Africa, Tanzania, Kenya. 77

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7 SÆTHER & KYEREMATEN: Rheotanytarsus phylogeny jongkindi Kyerematen et Sæther, 2000: 66. Gabon, D. R. Congo. kjaerandseni Kyerematen et Sæther, 2000: 69. Ghana. longicornus Kyerematen et Sæther, 2000: 41. South Africa. montanus Lehmann, 1979: 62. D. R. Congo, South Africa (Italy). ororus Lehmann, 1979: 64. D. R. Congo. plerunguis Kyerematen et Sæther, 2000: 37. Tanzania. remus Kyerematen et Sæther, 2000: 39. Ghana. rioensis Langton et Armitage 1995: 11. South Africa (Canary Islands). samaki Lehmann, 1979: 65. D. R. Congo, Ethiopia (Lebanon). transversus Kyerematen et Sæther, 2000: 47. Ghana. Nomina dubia in Rheotanytarsus abbreviatus Kieffer, 1925: 82. Argentina (Spies & Reiss 1996: 73). pentacritus Kieffer, 1921: 128. France (Ashe & Cranston 1990: 336). raptorius (Kieffer, 1909: 52). Germany, France (Ashe & Cranston 1990: 336). rivulorum (Kieffer in Kieffer & Thienemann, 1908: 81). Germany, France (Ashe & Cranston 1990: 336). Nomenclatorial notes. - The species R. muscicola, R. nigricauda, and R. pentapoda were originally described in Tanytarsus or Rheotanytarsus and their specific names must be assumed to be meant to be nouns in apposition. Their ending thus is not changed to be in accordance with the male gender of the genus. PHYLOGENY The species of Rheotanytarsus apparently fall into relatively easily defined species groups based on the pupa, while the imagines are more difficult to define. However, only 44 species out of a total of 94 species are known as pupae. Tentative groups for species with known pupae The described species can be grouped into four more or less distinct groups primarily based on pupal features, the ceratophylli, pellucidus, nigricauda, and curtistylus groups. The nigricauda and curtistylus groups include subtypes, which may each represent separate groups. Many species remain to be associated and placement of all imagines in these groups is not possible for the moment. However, some features allow placement of some of the imagines. The males of R. tamasecundus Sasa, R. oss Cranston, R. buculicaudus Kyerematen, R. contrerasi Andersen et Sæther and R. minusculus Kyerematen, for instance, are all nearly identical to that of R. pellucidus (Walker) differing only in minor mensural details. The pupae of the pellucidus group are characterised by having paired patches on tergites II-IV only, granulose frontal apotome and paired spine patches posteriorly on T II. The thoracic horn is often long with a median bend and has spines on the apical half. The caudal hooklets on tergite II occupy less than the median half. Segment VIII of the pupa has a compound spur with 1-10 teeth. The known male imagines often have a very long median volsella with the subulate lamellae often extending far beyond the apex of the superior volsella. However, in some species the apical setae of the median volsella are fused into plates. The male gonostylus sometimes may be hook-like, curved at apex. The group is treated by Kyerematen et al. (2000b). The pupae of the nigricauda group have transversely elongate or rectangular spine patches on all of tergites II-VI (nigricauda type), or II-V (guineensis type) or those on IV(V)-VI are more circular reissi -, fuscus-, and montanus-types. The thoracic horn of the nigricauda type is relatively short and completely bare. Segment VIII bears a single caudolateral spur without accessory teeth. The anal lobe bears a long dorsal seta. The L- setae on the segments are not taeniate. The gonostylus is evenly tapered in distal half. The pupae of the reissi type also have transverse elongate spine patches that are almost medially joined on tergites II and III (IV), while those on IV (V)-VI are more circular. T II is bare posteriorly. The thoracic horn is rather narrow and with at least some apical spinules. Segment VIII bears one caudolateral spur. The L-setae are taeniate on posterior abdominal segments. The male imagines may have the superior volsella sickle-shaped with posterior margin produced giving hook-like appearance and the gonostylus abruptly narrowed distally. The pupae of the fuscus type have paired rectangular spine patches on tergites II and III while those on T IV and V are rather circular. T II has a pair of transverse spine patches posteriorly. The frontal apotome is strongly tuberculous. The thoracic horn is either cylindrical and bare with a median bend, or long and thin with many spines on its apical ½ to ¾. Segment VIII bears 1 caudolateral spur. The male imagines may have the superior volsella sickle to oval-shaped and the gonostylus may or may not be distally narrowed. The pupa of R. guineensis appears rather isolated and may form a separate type. The pupa has paired rectangular patches on tergites II-V, but tergite II lacks posterior armament and tergites IV or V-VI with pos- Figs Rheotanytarsus spp., immatures R. ramirezae Kyerematen et Andersen, pupa. 14, frontal apotome; 15, thoracic horn; 16, abdomen R. curtistylus (Goetghebuer), larva. 17, antenna; 18, labro-epipharyngeal area; 19, mandible, 20, maxillary palp; 21, mentum. 79

8 TIJDSCHRIFT VOOR ENTOMOLOGIE, VOLUME 144, 2001 Fig. 22. Larval cases of Rheotanytarsus spp. (After Scott 1967). terolateral rugose area. The frontal apotome is usually smooth or wrinkled. The thoracic horn is often short and bare. Segment VIII has a single spur posterolaterally. The male imago has a slightly curved median volsella with several apical subulate or foliate lamellae fused into a plate with or without apical points. The gonostylus is often abruptly narrowed in apical half and curved at apex. The pupae of the rhenanus type have paired rectangular patches on tergites II and III and somewhat circular patches on tergites IV-VI. Tergite II has no posterior spine patches. The frontal apotome is wrinkled without tubercles and the thoracic horn is usually short, hyaline and bare, but may be slightly long and almost bare with just a very few spines apically. Segment VIII has one caudolateral spur. The male imagines may have a slightly curved median volsella and gonostylus abruptly tapering in distal half and sometimes recurved at apex. The pupae of the montanus type have transverse elongate spine patches on tergites II-IV and somewhat circular patches on tergites V and VI. In addition, tergite II has a transverse spine patch posteriorly. The frontal apotome is smooth and the thoracic horn is S-shaped and wide in the lower half, abruptly narrowing towards the apex, and almost completely bare with just a few spines in the apical part. Segment VIII has a single caudolateral spur. The male imagines have a somewhat knob-like extension apically on the superior volsella and a slightly S-shaped median volsella. The gonostylus tapers evenly to a point. The pupae of the ceratophylli group also have circular spine patches on tergites II-V(VI). T II has an additional pair of spine patches posteriorly. However, differing from other pupae of the genus, there are 2-6 curved spurs forming a comb posterolaterally on segment VIII (fig. 90). The thoracic horn may have spines on ¾ to its entire length and is usually heavily sclerotized apically. At least some larvae have median mental tooth with lateral notches and undivided pecten epipharyngis. The male imago has a very short median volsella with apical foliate setae partially or fully fused into a more or less distinct plate, and the anal tergite with triangular projections to each side of the anal point or sometimes with a straight posterior margin. The pupae of the curtistylus group are characterised by having paired circular patches on tergites II- V (curtistylus type) or on tergites II-VI (pentapoda type), and a posterior patch of spinules or shagreen on tergite II. The frontal apotome is often granulose apically. The thoracic horn is often long and thin, S- shaped, with a median bend and spines on apical ½ to ¾, but in a few cases, can be hyaline and mostly bare. Segment VIII has a single caudolateral spur which is often compound in the pentapoda type. At least some larvae have median mental tooth with lateral notches and undivided pecten epipharyngis. The male imagines have an S-shaped or at least curved median volsella with distal lamellae fused into a single plate with or without terminal points, or seldom a very short median volsella with separate distal subulate or foliate setae. Because of the lack of associated material for many species an attempt to delineate the cladogenesis of the sufficiently known species can only be regarded as tentative. As a first approximation, however, it may first be attempted to see if there are any objective synapomorphies delineating the preliminary groups. Subsequently the results, if reasonable, may be used as a constraint tree when attempting to outline the phylogeny of all known species. The genus Rheotanytarsus belongs to a well defined monophyletic group together with Paratanytarsus (Sæther 1977). The sister group relationship between Paratanytarsus plus Rheotanytarsus and Micropsectra Kieffer and related genera is equally clear as shown for instance by the similarly divided female gonapophyses VIII with a brush-like ventrolateral lobe. The distinct apodeme lobe of gonapophysis IX is an objective synapomorphy (Sæther 1983, 1988, 1990a, c) for Paratanytarsus plus Rheotanytarsus and there are several other putative synapomorphies between the two genera. 80

9 SÆTHER & KYEREMATEN: Rheotanytarsus phylogeny While the ceratophylli, the pellucidus and the nigricauda groups appear to be clearly monophyletic, the curtistylus group may not be. Objective synapomorphies for the ceratophylli group are: (1) pupa with caudolateral comb of 3-6 curved, thorn-like spurs, and (2) male tergite IX with shoulders or projections to each side of anal point. For the pellucidus group the only objective synapomorphy valid for all species are: (3) anterior spine patches absent on tergites V and VI, However, for most species with known pupae and some other clearly related species obviously forming the most derived subgroup an apical subgroup (4) the very long median volsella with the subulate lamellae often extending far beyond the apex of the superior volsella is unique. Also that the caudal hooklets on tergite II occupies less than the median ½ is common for nearly all species, but this feature occurs also in a few species apparently not belonging to the group. All species with known pupae of the nigricauda group have at least tergite II with transversely elongate or rectangular anterior spine patches (5). There are no corresponding objective synapomorphies in the male imagines. Although many males have the posterior margin of tergite VIII straight this is a feature also found in the ceratophylli group. In most species of the group in its strictest sense (i.e. with rectangular spine patches on more tergites than tergite II) the superior volsella has posterior margin hook- or knob-like. However, this is found also in some other species. In the curtistylus group there appear to be no objective synapomorphies. No characters are unique to the group and the group is likely to be para- or polyphyletic. The species delineated by possessing the above synapomorphies 1-5 should form the base and part of eventual constraints in parsimony analyses. Parsimony analysis Since few species are known as pupae and this stage obviously is the most phylogenetically important, trends in the pupa should form the basis for constraints. However, also in the pupae several characters are not mentioned in the descriptions and several more may not have been properly observed. In addition to the missing knowledge of immature stages there are several undescribed Nearctic species (Hudson et al. 1990, Caldwell et al. 1997). According to J. E. Sublette (pers. comm.) there are about 15 undescribed Nearctic species. The data can be scored in a number of ways. In Kyerematen (1999) several ordered multistate trends were used. However, the different states of one character should be of the same level, the same scholastic fundamentum divisiones. For instance presence and absence of spine patches on a tergite are not comparable with and should not be in the same trend as circular versus rectangular patches. In the data matrix used here such characters are divided into several trends. In order not to have absence data heavily weighted not applicable is used for instance for absence of patches in characters comparing circular versus rectangular patches. That raises an additional problem with parsimony analyses: absence, not applicable, unknown and polymorphism all are treated in the same way by the programs, i.e. as 0&1. Gaps, i.e. not applicable, can also be scored as additional characters. However, that may result in groupings based on non-existing characters and thus is not feasible. The data matrix used here may give the shortest trees but will have a tendency to render monophyletic groups paraphyletic since the not applicable score will be the same as the preceding score more basally in the cladogram. Parsimony analyses with the same matrix, but with all not applicable scored as zero thus also was performed. This exaggerates the number of steps needed and also amounts to polarising the trends, but the groupings should be more reliable and the polarising appears quite obvious in the characters used here. The correct number of steps can be found by using the data matrix with not applicable scored as 0&1 for the results obtained with not applicable scored as 0. In order to determine the phylogeny of the genus all previously described species were re-examined from specimens available or from the literature and the following trends 1-82 erected. Different parsimony analyses using PAUP 4.0b8 (Swofford 1993) and MacClade 3.08a (Maddison & Maddison 1996) on a Power Macintosh 8200/120 and an ibook performed. No trends for the larvae were used below since the larvae for nearly all of the included species are unknown or undescribed and parsimony programs have difficulties in separating polymorphies from unknown character states. The genus Paratanytarsus, which almost certainly forms the sister group of Rheotanytarsus, was scored for the same characters and included in the analyses. The genus Stempellina Thienemann et Bause was used as an outgroup. All original searches were heuristic with 1000 replicates. However, overflow regularly occurred and searches terminated prematurely. Characters and states used in the phylogenetic analyses Imagines 1. Antennal ratio: (0) < 0.61; (1) > This and other mensural features are somewhat subjectively divided based on the distribution among species and experience from other chironomid genera. For instance a normal, non-reduced 81

10 TIJDSCHRIFT VOOR ENTOMOLOGIE, VOLUME 144, 2001 Figs Rheotanytarsus spp., male imago Tergite IX showing different types of anal tergite band; 23, R. abonae; 24, R. baculus; 25, R buculicaudus; 26, R,. fuscus; 27, R. minusculus; 28, R. koraensis; 29, R. pallidus; 30, R. verticillus Caudal margin of tergite IX; 31, R. additus; 32, R. atrius; 33, R. baculus; 34, R. ceratophylli; 35, R. contrerasi; 36, R. foliatus; 37, R. ororus Anal point; 38, R. additus; 39, R. falcipedius; 40, R. guineensis; 41, R. pallidus; 42, R. remus; 43, R. sessilipersonatus; 44, R. verticillus. 82

11 SÆTHER & KYEREMATEN: Rheotanytarsus phylogeny antenna nearly always has an antennal ratio higher than 0.6, while lower antennal ratios indicate reductions often corresponding to other reductive features. 2. Flagellomeres: (0) 13; (1) 12. Up to recently all species of Rheotanytarsus were assumed to possess 13 flagellomeres. Kyerematen & Sæther (2000) and Kyerematen et al. (2000a), however, described three species respectively from Malaysia and Ghana with only 12 flagellomeres. Unless the antenna was lost it thus is assumed that all previously described species except for these three species have 13 flagellomeres. 3. Ground colour of thorax: (0) pale; (1) slightly dark; (2),very dark. 4 Leg coloration: (0) pale; (1) segments dark apically; (2) entirely dark. 5 Mid tibia: (0) with 2 spurs; (1) with 0-1 spur. 6. LR 1 : (0) < 2.0; (1) ; (2) > Wing length: (0) < 0.99 mm; (1) mm; (2) > 2.50 mm. The character alternatives here could also be given as small, medium and large size and are divisions generally used for chironomids. 8 Vein M: (0) bare; (1) setose. 9 Vein Sc: (0) bare (fig. 3); (1) setose. The presence or absence of setae on the subcostal vein of the wing is seldom mentioned in descriptions. However, the wings are often illustrated and it has been assumed that the figures are accurate concerning presence or absence of setae on subcosta even if this may not always be the case. 10 Setae on Cu: (0) < 10; (1) > 9 (fig. 3). 11. RM: (0) bare; (1) setose (fig. 3). 12. Abdomen: (0) pale; (1) dark. 13. Abdomen: (0) not banded; (1) banded. 14. Basal tergite band of tergite IX: (0) absent (figs. 4, 24); (1) present (figs. 27, 28, 29). 15. Basal tergite band: (0) not medially joined; (1) medially joined (figs. 26, 28, 29) 16. Anal tergite bands: (0) transverse or absent; (1) V- shaped (figs. 4, 24). 17. V-shaped tergite band: (0) weakly developed; (1) strongly developed (figs. 4, 24). 18. V-shaped bands; (0) not joined medially (figs. 4, 24); (1) joined medially. 19. Transverse anal tergite bands: (0) medially joined; (1) not joined medially. 20. Setae between or just posterior to bands: (0) present; (1) absent. 21. No. of setae between or just posterior to bands: (0) > 3; (1) 1-3 setae. 22. Anal point crest: (0) basally rounded crest (figs. 38, 40, 41); (1) V-shaped or open (figs. 4, 39, 42-44). 23. Anal point crest: (0) V-shaped or basally rounded but short (fig. 40); (1) basally rounded and long. 24. Anal point: (0) parallel-sided or tapering; (1) spatulate (figs. 38, 39, 43). 25. Anal point: (0) more than ½ as wide as width of superior volsella, parallel-sided or tapering (figs. 40, 42); (1) at most ½ as wide as width of superior volsella, parallel-sided or tapering. 26. Posterior margin of tergite IX: (0) triangular or at most rounded (figs. 4, 32, 33, 35, 37); (1) straight or with projections or shoulders to each side (figs. 31, 34, 36). 27. Posterior margin of tergite IX: (0) straight; (1) with projections or shoulders. 28. Digitus of superior volsella: (0) extending beyond margin (figs. 45, 48, 53); (1) not extending beyond margin. 29. Superior volsella: (0) rounded, ovoid or oblong (figs. 46, 48, 52); (1) with posterior margin produced (figs. 6, 45, 47, 49-51, 53). 30. Superior volsella: (0) without apical projection; (1) with (figs. 6, 45, 47, 49, 50, 51, 53). 31. Superior volsella: (0) with knob-like apical projection (figs. 45, 47, 49, 50, 53); (1) with hook-like or pointed apical projection (figs. 6, 51). 32. Median volsella: (0) reaching beyond apex of superior volsella (fig. 6); (1) not extending beyond apex of superior volsella. 33. Median volsella: (0) not reaching apex of inferior volsella (fig. 6); (1) reaching or surpassing apex of inferior volsella 34. Median volsella: (0) with cochleariform, spatulate, foliate, subulate or simple setae but setae never fused into plate(s) (figs. 54, 59); (1) setae fused into plate(s) apically (figs. 7, 8, 55-58, 60-63). 35. Plate(s) of median volsella: (0) rounded without points; (1) with points (figs. 7, 8, 56, 57, 63). 36 Gonostylus: (0) not abruptly tapered; (1) abruptly tapered in apical portion (figs. 4, 5, 66, 89, 70, 72, 73). 37. Gonostylus: (0) without parallel-sided apical portion; (1) with (figs. 72, 73). 38. Apex of gonostylus: (0) not curved; (1) curved (fig. 70). 39. Gonocoxite to gonostylus: (0) shorter (fig4); (1) equal to or longer. Female (Characters are excluded from most parsimony runs since they to a large extent consist of mensural features and since they are unknown for a plurality of species.) 40. Antennal ratio: (0) > 0.29; (1) < Tentorium length: (0) > 94 µm; (1) < 95 µm. 42. Ground colour of thorax: (0) pale; (1) medium; (2) dark. 43. Wing length: (0)< 1.0 mm; (1) mm; (2) < 2.0 mm. 83

12 TIJDSCHRIFT VOOR ENTOMOLOGIE, VOLUME 144, 2001 Figs Rheotanytarsus spp., male imago Superior volsella; 45, R. angustus; 46, R. atrius; 47, R. acuminatus; 48, R. digitatus; 49, R. exiguus; 50, R. foliatus; 51, R. falcipedius; 52, R. plerunguis; 53, R. samaki Median volsella; 54, R. acerbus; 55, R. adjectus; 56, R. flabellatus; 57, R. hanseni; 58, R. kjaerandseni; 59, R. pellucidus; 60, R. pelus; 61, R. plerunguis; 62, R. sessilipersonatus; 63, R. verticillus.. 84

13 SÆTHER & KYEREMATEN: Rheotanytarsus phylogeny 44. Front leg ratio: (0) < 2.00; (1) ; (2) > Seminal capsule: (0) dark sclerotized; (1) not dark sclerotized. 46. Seminal capsule neck: (0) present (fig. 46); (1) absent. 47. Gonocoxite: (0) setose; (1) bare. 48. Tergite IX setae: (0)< 20; (1) 20-30; (2) > Notum length: (0) < 100 µm; (1) > 100 µm. Pupae 50. Frontal apotome: (0) smooth or wrinkled (figs. 14, 78); (1) rugulose at least anteriorly (figs ). 51. Frontal apotome rugolosity: (0) not extensive; (1) extensive (fig. 76). 52. Frontal setae: (0) absent (figs. 76, 78); (1) present (figs. 14, 74, 75, 77). 53. Median bend of thoracic horn: (0) present (figs. 15, 79, 80, 82); (1) absent (figs. 81, 83, 84). 54. Thoracic horn length: (0) > 550 µm; (1) µm; (2) < 200 µm. 55. Thoracic horn: (0) with spinules; (1) bare (figs. 83, 84). 56. Thoracic horn: (0) with setae or points in apical ⅔-¾; (1), in apical ½; (2) in apical ⅓-¼. 57. Paired anterior spine patches of tergite II: (0) absent; (1) present. 58. Spine patches of tergite II: (0) circular to oval (figs. 16, 86, 88);(1) rectangular or transverse (figs. 85, 87). 59. Spine patches of tergite II: (0) rectangular (fig. 85); (1) transversely elongate (fig. 87). 60. Tergite II posteriorly: (0) bare (figs. 85, 87); (1) with shagreen (figs. 16, 86, 88). 61. Posterior shagreen of tergite II: (0) not arranged into 2 groups (fig. 86); (1) 2 groups of spinule patches (figs. 16, 88). 62. Extent of caudal hooklets of tergite II: (0) occupying median ½-¾; (1) median ⅓-½; (2) less than median ⅓. 63. No. of caudal hooklets: (0) > 70; (1) hooklets; (2) < Tergite III patches: (0) paired circular patches or absent: (1) rectangular or transverse. 65. Tergite III patches: (0) rectangular; (1) transversely elongate. 66. Tergite IV patches: (0) circular; (1) rectangular or transverse. 67. Tergite IV patches: (0) rectangular; (1) transversely elongate. 68. Tergite V: (0) with anterior, lateral or posterior patches or longitudinal bands of spines; (1) completely bare except for shagreen. 69. Tergite V patches: (0) circular; (1) rectangular or transverse. 70. Tergite VI: (0) without anterior spine patches; (1) with paired patches anteriorly. 71. Tergite V: (0) with shagreen; (1) bare. 72. Shagreen of tergite V: (0) weak caudolateral, anterolateral, median or anterior shagreen (1) extensive. 73. Shagreen of tergite VI: (0) over whole tergite (or bare); (1) anterior or median shagreen only. 74. Segment VIII: (0) with caudolateral comb of 3-11 brown teeth in single row or with single or multiple spur (figs. 16, 89); (1) with comb of 3-6 curved, thorn-like spurs (fig. 90). 75. Segment VIII: (0) with caudolateral comb or with single or cleft spur; (1) with spur consisting of 1-10 teeth. 76. Taeniate L setae: (0) present (fig. 16); (1) absent. 77. Taeniate L setae: (0) each of segments II-VII with at least 1 taeniate L seta; (1) no taeniate L setae on segments II- IV. 78. Anal lobe fringe taeniae: (0) > 20; (1)10-20 taeniae; (2) < 10 taeniae. R. samaki is the only species lacking setae on the anal lobe. This autapomorphy is regarded as not applicable for the species rather than adding an additional character state. 79. Dorsal seta of anal lobe: (0) present; (1) absent. 80. Dorsal seta of anal lobe: (0) taeniate; (1) hair-like. The datamatrix with the character states for the species of Rheotanytarsus is presented in table 1. However, since not all species of the genus were re-examined physically, several of the scorings are somewhat subjective. It has, for instance, been assumed that if nothing else is mentioned in the descriptions the characters conform to the generic diagnosis. Up to recently all species of Rheotanytarsus were assumed to possess 13 flagellomeres. Kyerematen & Sæther (2000) and Kyerematen et al. (2000a), however, described three species respectively from Ghana and Malaysia with only 12 flagellomeres. Unless the antenna was lost it thus is assumed that all previously described species except for these three species have 13 flagellomeres. Similarly the presence or absence of setae on the subcostal vein of the wing is seldom mentioned in descriptions. However, the wings are often illustrated and it has been assumed that the figures are accurate concerning presence or absence of setae on subcosta even if this may not always be the case. The description of the pupa of R. adjectus by Zavřel (1934) is limited to stating that the pupa is not separable from the European R. muscicola. Accordingly, the character states for R. adjectus are scored identical to those for R. muscicola even if it is not unlikely that there may exist some differences. Similar evaluations exist for several other characters such as the tibial spurs, the digitus, anal tergite bands, presence or absence of plate on median volsella, and, for the pupae, shape of spine patches, extent of shagreen, and pres- 85

14 TIJDSCHRIFT VOOR ENTOMOLOGIE, VOLUME 144, 2001 Figs Rheotanytarsus spp., male imago. Hypopygium, gonostylus; 64, R. acuminatus; 65, R. angustus; 66, R. baculus; 67, R. buculicaudus; 68, R. bufemoratus; 69, R. falcipedius; 70, R. guineensis; 71, R. pellucidus; 72, R. remus; 73, R. phaselus. ence, absence and shape of dorsal anal lobe seta. The scoring of the trends or characters is based on all available data including both from the literature and from examined material. In a few cases where, for instance, the wing length of the male could not be measured while the wing length of the female was available, the scoring could be estimated provided the female were of the same type as in the male. The opposite is not equally possible since the female wing often is of a quite different type concerning length and width. Similarly some scoring can be judged from published figures. In a few cases the scoring is not one hundred percent in accordance with the measurements given. The front leg ratio of R. atrius, for instance, is with a mean of 2.89 and strictly speaking the scoring for character 6 should be 1&2. However, had the highest LR been 3.04 (=3.0 using one decimal) the scoring would have been 1 and we find it more meaningful for parsimony analyses to make the score 1. There are a number of potential additional trends particularly in the chaetotaxy of the superior and median volsellae and in the shape of the median volsella. When these are not included in the analyses it is because descriptions and available slide preparations of previously described species to a large extent are inadequate. Different positioning on the slide results in 86

15 SÆTHER & KYEREMATEN: Rheotanytarsus phylogeny quite different appearance of the median volsellae and may also result in that eventual plates or spines on plates are overlooked or misinterpreted. Many slide preparations are bad, of teneral specimens, or not cleared. A few of the potential trends are incorporated in the first constraint tree. R. kyotoensis and R. thermae, for instance, both have apically bifid median volsella, an obvious potential synapomorphy which, however, may have been overlooked in some other species. The data have been analysed in a number of different ways: All species and characters included with non-applicable automatically scored as 0&1, scored as 0, unordered or ordered, not weighted or weighted according to the rescaled consistency index (RC); the same with female characters excluded, the same with only species known as male included; the same with only species known as pupae included; the same with only male characters, and the same with only pupal characters included. The results based on all characters, females excluded, and on males only give largely untenable results with more than 40,000 trees, homoplasy indexes (HI) of before exclusion of uninformative characters and little similarities between the different analyses. However, some monophyletic groups and sister group relationships are common for all analyses. Rheotanytarsus essentially always comes out monophyletic. The exception being for some analyses including only species known as pupa and including pupal characters only. R. aestuarius and R. dogoensis nearly always form a pair. However, primarily since they have a banded abdomen as in R. trivittatus and R. ceratophylli, and not found in any other Rheotanytarsus, they sometimes are inside that group. R. ceratophylli, R. additus, and R. trivittatus form one monophyletic group when all characters are included, while R. additus sometimes falls outside the group especially in the analyses of pupal characters. Both R. additus and R. trivittatus are polymorphic for character 70, presence or absence of spine patches on tergite VI. However, while R. trivittatus always falls together with R. ceratophylli, with presence of spine patches regarded by the analysis as a synapomorphy; R. additus often pair up with a species without spine patches and the absence regarded as a synapomorphy. Some species known only as imagines nearly always come close to R. trivittatus and relatives, primarily based on the combination of shoulders to each side of the anal point or at least straight posterior margin of tergite IX (characters 26 and 27), spatulate anal point, and short median volsella. This group is here named the trivittatus group in order to separate it from the ceratophylli pupal group based on the analysis above. Likewise is the nigricauda group changed to the guineensis group. The three species with 12 flagellomeres based on male characters always fall in a monophyletic or paraphyletic group of small species (wing length less than 0.99 mm), with rounded superior volsella and not abruptly tapered gonostylus, the aquilus group. R. rivulophilus comes out together with R. kyotoensis. Based on pupal characters R. petropholeter and R. barrengaryensis always come together with R. hamatus and R. exiguus in the same group. The male characters nearly always indicate R. pelus as the sister species of R. hamatus. The pupal characters also always combine R. juliae and R. underwoodi. R. ringei, R. jongkindi and R. pantanalensis have somewhat variable sister species in the different analyses, but their sister species always belong to the guineensis group. R. atrius and R. kjaerandseni, always come out together and with R. tamasecundus. However, the last species belongs in the pellucidus group, while R. kjaerandseni do not. More or less clear species pairs based on male characters are R. remus and R. photophilus, and R. kuramasimplex and R. okisimplex. R. sessilipersonatus, R. baculus, and R. soelii also come out together. However, most of the above results are very tentative since the number of trees mostly exceeds 40,000 causing overflow and the homoplasy index (HI) is higher than It is well known from chironomid groups that the pupal and female characters are more conservative than male and larval characters and should thus be better for finding groups within a genus. An indication here is that the number of trees when pupal characters alone (including only species known as pupa) are analysed, although high, mostly are below 40,000 and the HI before weighting and after exclusion of uninformative characters, and and 0.49 after reweighting according to RC. The groups based on a particular set of synapomorphies (the objective trends 1-5 mentioned above) largely hold in the parsimony analyses. The reweighted results based on described pupal characters only is shown in figs. 91, 92. The pellucidus group is monophyletic when not applicable is scored as 0&1, while R. flabellatus falls close to R. ceratophylli when not applicable is scored as 0. R. additus in both cases falls outside the trivittatus group. R. ramirezae in both cases is close to R. ceratophylli. Accordingly species close to R. ramirezae based on male characters also should be included in the group. The guineensis (nigricauda) group is divided in three groups. When not applicable is scored as 0&1 there are two monophyletic groups, the larger with 8 species and including R. guineensis, the smaller with 6 species and including R. fuscus. R. samaki forms a separate group. When not applicable is scored as 0 R. gloveri, R. christinae plus R. tamaquartus comes to- 87