Setodytes Schwank, 1990

Balsamo, Maria, Pierboni, Lara & Grilli, Paolo, 2009, Taxonomic and nomenclatural notes on freshwater Gastrotricha, Zootaxa 2158, pp. 1-19 : 6-7

Subgenus Setodytes Schwank, 1990

Schwank, P. 1990, Gastrotricha. In: Brauer A. (Ed) Süsswasserfauna von Mitteleuropa. Bd. 3/ 1: 1–252. G. Fischer Verlag, Stuttgart, p. 45.

Type species: Dasydytes (Setopus) tongiorgii Balsamo, 1982 ; designation by Schwank (1990)

According to Schwank (1990, p. 42) the genus Dasydytes includes 3 subgenera: D. ( Dasydytes s.s.), D. ( Setodytes ) and D. ( Setopus ). Schwank established the subgenus Dasydytes (Setodytes) in order to distinguish Dasydytes (S.) tongiorgii , D.(S.) chatticus and D.(s.) lemnicola (nomen nudum) from the rest of the species in the subgenus D. ( Setopus ), because provided with spines with an accessory point. The former two species show also two peculiar caudal spines of different length and with an accessory point. However, both the spines with an accessory point and the unequal caudal spines are characters present in other species of Dasydytidae , and do not appear to be diagnostic at subgeneric level.

Thus, the subgenus Dasydytes (Setodytes) is synonymized with the genus Setopus ( syn . nov.), a taxon which has to be considered at a generic level, according to the original description by Grünspan (1908) and the emended diagnosis by Kisielewski (1991). The freshwater genus Dasydytes counts now two subgenera ( Dasydytes sensu stricto , Prodasydytes ).

Chaetonotida Paucitubulatina currently include 7 families ( Chaetonotidae , Dasydytidae , Dichaeturidae , Muselliferidae , Neogosseidae , Proichthydidae , Xenotrichulidae ) and 28 genera. Four families ( Dasydytidae , Dichaeturidae , Neogosseidae , Proichthydidae ), with 12 genera, are exclusively freshwater. Chaetonotidae are composed of 12 genera, 5 of which are only freshwater ( Arenotus , Fluxiderma , Polymerurus, Romballichthys and Undula ), 5 have both freshwater and marine species ( Aspidiophorus , Chaetonotus , Heterolepidoderma , Ichthydium , Lepidodermella ), and 2 are exclusively marine ( Caudichthydium , Halichaetonotus ). Muselliferidae , with 2 genera ( Diuronotus , Musellifer ) and Xenotrichulidae , with 3 genera ( Draculiciteria , Heteroxenotrichula , Xenotrichula ) comprise exclusively marine species.

The complete list of the world freshwater species of Gastrotricha currently considered as reliable species, and indicated with the updated taxonomic name, is given in the Appendix, also including the only two species incertae sedis of Macrodasyida which have been found in fresh waters. For completeness also the species inquirendae, the species incertae sedis and the nomina nuda are reported, and the updated numbers of the reliable species (both freshwater and marine) of each genus and subgenus is given.

This checklist is a part of a complete dataset of freshwater species of Gastrotricha of the world, which includes taxonomical comments and geographical distribution at biogeographical region and/or at country/ State level of each species, as well as a list of the bibliographic references. This dataset, nearing completion, w i l l b e p u b l i s h e d a n d m a d e f r e e l y a c c e s s i b l e a t t h e w e b s i t e o f FA D A p r o j e c t [h t t p:/ / www.fada.biodiversity.be].