Towards phylogeny and zoogography of the genus rheotanytarsus thienemann et bause, 1913 (diptera: Chironomidae)

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. E-mail: [email protected].