Cytogenetic characterization of an endemic mahseer, Tor mosal mahanadicus (David, 1953; Teleostei : Cyprinidae)

Abstract

The Tor mosal mahanadicus (David, 1953) is an endangered mahseer species well known for its high food value. The taxonomy of the species is confusing owing to the morphological variations and the habitat adaptations. These taxonomic ambiguities need to be resolved for development of strategies for their rehabilitation and use in aquaculture. The cytogenetic markers have been considered as authentic and robust tools to resolve taxonomic ambiguity among the groups of fishes. The cytogenetic characteristics were investigated in T. mosal mahanadicus using karyotyping, Ag-NOR and fluorescence (CMA3) staining techniques. The basic diploid chromosome number (2n) was observed to be 100 and the karyotype formula and fundamental arm number (FN) were derived as 22m + 12sm + 22st + 44t and 134, respectively. Silver and CMA3 staining of the metaphase chromosomes revealed presence of multiple nucleolar organizer regions (3 pairs). The information on cytogenetic study of this mahseer species has been discussed in the light of cytotaxonomic implications.