Taxonomic Studies on Species of the Genus Systomus McCelland From Kerala

Abstract- The ‘Olive barb‘ Systomus sarana described erstwhile from the ponds and rivers of Bengal by Hamilton in 1822 is the only representative of the species of the genus Systomus McClelland so far known in India. The species is known to have seventeen synonyms in India alone including three from the southern state of Kerala and all these synonymisation process had been carried out without proper taxonomic studies. In the present study, by using integrative taxonomic tools (Morphological, Anatomical, Mitochondrial genetics) species level diversity of the genus Systomus McClelland, 1838 is examined. The results reveal that there are at least three species of Systomus in India including S. sarana. Systomus sarana is distributed throughout the Ganges and the larger eastward flowing rivers of Brahmaputra, Parma ,Godavari, Krishna, Cauvery and westward flowing Narmada in central India. Systomus gibbosus (Valenciennes, 1842) is the oldest available name for the next most widely distributed species ; present in Kerala, Southern Karnataka, all the way up to the smallest rivers of Raigad district in Maharashtra and Narmada river system in central India. The third but highly restricted species with the available name S. subnasutus is found only in the east flowing Cauvery river and its tributaries. The results based on genetic analysis do not support an eastward and westward separation of the species. This may possibly be due to introduction, subsequent movement of fingerling and brood stock enhancement which need to be studied in detail.