Lepidochaetus Kisielewski, 1991

Balsamo, Maria, Pierboni, Lara & Grilli, Paolo, 2009, Taxonomic and nomenclatural notes on freshwater Gastrotricha, Zootaxa 2158, pp. 1-19 : 3-4

Genus Lepidochaetus Kisielewski, 1991

Kisielewski J. 1991. Inland-water Gastrotricha from Brazil. Ann. Zool. (Warszawa) 43 (2), p. 10 Typus generis: Lepidochaetus brasilense Kisielewski, 1991; original designation.

The genus Lepidochaetus was introduced by Kisielewski (1991) to group some freshwater species previously included in the genus Chaetonotus , characterized by numerous, rounded, unkeeled scales, provided with long and thin spines covering both the dorsal and the ventral body surfaces. According to Kisielewski’s (1991, 1997) phylogenetic views, this cuticular morphology would be plesiomorphic in the Chaetonotida . Other more complex morphological patterns would have arisen from this one, generally different on the dorsal and on the ventral body surfaces, as it is the usual condition in the species of genus Chaetonotus . The latter is a very large genus which includes both freshwater and marine species: Remane (1936) had already divided the genus on morphological criteria into 9 ‘groups’, to only two of which he recognized a subgeneric rank [C. ( Zonochaeta ) and the marine C. ( Halichaetonotus )]. In his systematic revision of the freshwater species, Schwank (1990) divided the genus Chaetonotus into 8 subgenera (including [C. ( Zonochaeta )], all but one, [C. (Nudichaetonotus)] corresponding to the Remane’s groups. A new subgeneric division of the whole genus Chaetonotus was then introduced by Kisielewski (1997), who recognized 8 subgenera, accepting those previously created by Schwank except for two [C. ( Bifasciculatella ) and C. ( Diversichaetatella )] and introducing three others: C. ( Primochaetus ), C. ( Captochaetus ) and C. ( Marinochaetus ), the last one entirely marine.

However, the main morphological features diagnostic of the genus Lepidochaetus (large kephalion with a free caudal edge, round-rectangular scales with double anterior edge, some dorsal and lateral rear scales with long, straight spines, ventral cuticular covering agreeing in number and character of structures with the dorsal and lateral ones) cannot be unambiguously distinguished from those of the genus Chaetonotus to which most species of Lepidochaetus were previously assigned. For this reason Lepidochaetus should no longer be considered as a separate genus but rather as a subgenus of Chaetonotus ( syn . nov.).

Five species were originally included in this genus: L. brasilense Kisielewski, 1991 , L. carpaticus (Rudescu, 1967) ; L. ornatus (Daday, 1901) , L. pusillus (Daday, 1905) , L. zelinkai (Grünspan, 1908) . When moved into Chaetonotus , Lepidochaetus brasilense Kisielewski, 1991 becomes Chaetonotus brasilensis , a secondary junior homonym of Chaetonotus brasiliensis Schwank, 1990 . We propose here the new name Chaetonotus brasilianus (nomen novum), as a replacement name for Lepidochaetus brasilense Kisielewski, 1991 nec Schwank, 1990. L. pusillus (Daday, 1905) has been successively moved by Kisielewski (1997) into the subgenus Chaetonotus s.s. and thus is now Chaetonotus (C.) pusillus (Daday, 1905) . The other 3 species are thus retained in Chaetonotus (Lepidochaetus) , as Chaetonotus (L.) carpaticus (Rudescu, 1967) , Chaetonotus (L.) ornatus (Daday, 1901) , and Chaetonotus (L.) zelinkai (Grünspan, 1908) .

Because of the change from a generic to a subgeneric rank within the genus Chaetonotus , the original diagnosis of Lepidochaetus (Kisielewski, 1991, p. 10) is emended as follows: