Revision of gonius subgroup of the Genus Labeo Cuvier, 1816 and confirmation of species status of Labeo rajasthanicus (Cypriniformes: Cyprinidae) with designation of a neotype

Abstract

The fish species, Labeo rajasthanicus was first described from Jaismund Lake in western Rajasthan region, India, based on a single specimen and has never been reported since its first description in 1970. The taxonomic status of the fish has not been stable due to the conflicting opinion among several authors either as a valid species or as a synonym of L. boggut. The present report redescribes the species L. rajasthanicus based on the specimen collected from its type and other adjoining localities, with confirmation of its taxonomic status as valid species and designation of a neotype as the holotype specimen is no longer available. Morphometric and molecular data, distinguish this species from its congeners under genus Labeo, namely L. gonius, L. boggut and L. dussumieri. Analysis of the morphometric and meristic data as well as truss measurements of all the four species confirmed its identity. Among all the morphometric and meristic characters, anal fin rays showed significant differences (p<0.05) between the four species. Divergence in cytochrome oxidase c subunit I (COI) sequences also indicated species level separation of L. rajasthanicus from other species of gonius group of the genus Labeo. Genetic and morphological evidences support the distinction of L. rajasthanicus as a separate species from all related congeners and an identification key has also been proposed.