Molecular evidence indicates the existence of multiple lineages of Sperata in Indian Rivers

Abstract Understanding the population genetic structure and species boundaries in the complex river system has been challenging. The genus Sperata, a commercially important and widely distributed freshwater catfishes of India, belongs to Bagridae. The taxonomy of the Sperata genus is complex and still under revision. Recently, five valid species of Sperata were described from the Indian subcontinent. To determine the species boundaries and presence of taxonomic units within the Spereta, we analyzed the sequences of mitochondrial DNA (mtDNA) cytochrome c oxidase I (COI) and control region (CR) from Ganga, Gomti, Brahmaputra and Mahanadi river. The analysis of species delimitation using the COI gene indicated the presence of multiple taxonomic units among Sperata. Similarly, CR suggested the high haplotype diversity in S. lamarrii with a signature of demographic expansion in the Ganga river. In this study, we identified S. cf. lamarrii, a new lineage from the lower stretch of Ganga, another Sperata sp. from the Brahmaputra, Surma (Bangladesh) river, and from an unknown locality. It also highlighted that the Brahmaputra river also holds a highly diverse lineage that genetically qualifies the status of distinct species. Our finding suggests that multiple lineages of Sperata existed in the Indian River system; therefore, these should be considered a different management unit to protect contamination of natural stock. This study can be further used as a reference database for proper lineage identification within Sperata to formulate appropriate conservation and management plans.