Taxonomic quest: validating two mahseer fishes (Actinopterygii: Cyprinidae) through molecular and morphological data from biodiversity hotspots in India
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.
KeywordsMahseer Tor Northeast India Brahmaputra Barak Eastern Himalaya Indo-Burma DNA barcoding Conservation
We are thankful to the Director, Zoological Survey of India, Kolkata, for providing necessary facilities through core funding of the organization; and the Department of Forest, Government of Assam for necessary permission of sampling. We also acknowledge the research funding from the Science and Engineering Research Board, Department of Science and Technology, Ministry of Science and Technology, Government of India, New Delhi, in favor of Boni Amin Laskar (SB/FT/LS-162/2012) and Shantanu Kundu (PDF/2015/000302). We thank Madeline Jarvis-Cross, a native English speaker of University of Toronto, Canada, and Dr. B. I. Choudhury, University of Toronto, Canada for technical and linguistic improvement in the MS.
BAL, and VK conceived and designed the experiment; BAL and SK collected and identified specimens; BAL captured photographs of fishes; BAL, VK and KC contributed chemicals; SK, KT and BAL generated DNA data; BAL did taxonomic and morphological analysis; VK, SK, and BAL analyzed the sequence data; BAL wrote the manuscript text; BAL, SK and VK prepared the figures; all authors reviewed the manuscript.
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