An Extensive Taxonomic Analysis of Catfish Species (Family: Bagridae) Using Mitochondrial DNA (mtDNA) from the Cauvery River Basin in Tamil Nadu, India

Abstract

The present study investigates the morphological, molecular, osteological, and evolutionary aspects of freshwater Bagrid catfish in the Western Ghats of India, focusing on the Cauvery River basin. Samples from three genera of the Bagridae family, namely Hemibagrus, Sperata, and Mystus, were collected from the Cauvery and Bhavani rivers. The study aims to assess the diversity and threatened status of Bagridae catfishes in the region, identify morphological discrimination using mitochondrial DNA (mtDNA), analyze phylogenetic relationships, and understand their evolutionary process from common ancestries. Morphological and meristic characterization was performed, and genetic analysis was conducted using the cytochrome oxidase subunit 1 (COX1) gene. DNA was extracted from tissue samples, amplified using specific primers, and sequenced. The study highlights the need for taxonomic revision of Bagridae catfishes in the Western Ghats, as previous classifications were primarily based on morphometric analysis, leading to confusion and invalid species claims. The findings contribute to a better understanding of the diversity, taxonomy, and evolutionary history of Bagrid catfishes in the Western Ghats, which is crucial for their conservation, as more than 50% of the species are threatened with extinction due to various factors such as pollution, biological resource use, and habitat modification.