Taxonomic quest: validating two mahseer fishes (Actinopterygii: Cyprinidae) through molecular and morphological data from biodiversity hotspots in India

Abstract

Mahseers, the members of the fish genus Tor, are economically important as sport and food fishes, but their population is declining in South and Southeast Asia. Taxonomic discrepancies exist in discussions surrounding a few species of mahseer in India. In this study, we hypothesize that Tor mosal is wrongly synonymized with T. putitora, and T. barakae with T. tor. To test this, we collected samples from the type localities, and from known distribution areas. We observed a clear morphological distinctiveness among these four species using Principal Component Analysis. The most prominent distinctive parameters among the four species were body depth and head length. Phylogenetic analysis using Bayesian Inference and Maximum Likelihood for both partial mtCOI and mtCytb datasets revealed monophyletic origin, and supported distinctive species level delimitation which was consensus with morphological identity. Moreover, the automatic species delimitation methods (ABGD and PTP) also quantify the four species. The mean K2P distance was 1.57% between T. putitora and T. tor, 2.60% between T. mosal and T. putitora, 3.27% between T. mosal and T. tor, and 2.63% between T. barakae and T. tor. Based on this study, we validate T. mosal and T. barakae, and provide taxonomic keys to the species.