Taxonomic assessment of Puntius thermalis in Sri Lanka using DNA barcoding

Abstract

Puntius chola (sensu lato) Hamilton 1822, (family Cyprinidae) is a widely distributed fish species in the Asian region. The recent taxonomic revision of the genus Puntius revived the name Puntius thermalis (sensu stricto) Valenciennes 1844 for Sri Lankan specimens previously identified as Puntius chola. The use of DNA barcoding for the identification of species is now widely recognized, and a large number of taxonomic studies have used mitochondrial Cytochrome Oxidase I (COI) gene sequences to delineate fish species. The objective of this study was to use DNA barcoding to clarify taxonomic status of Puntius chola (s.l.) in Sri Lanka. DNA sequences of the partial mitochondrial COI gene region were produced, and alignment based comparisons were made with additional COI sequences for Indian P. chola and two selected out-group cyprinid taxa available from the Genbank. According to the derived phylogenetic tree, P. chola in Sri Lanka (4 locations) is clearly separated from Indian P. chola. The divergence levels between Sri Lankan and Indian P. chola ranged from 2.2% to 14.9%. There were no significant phylogenetic differences found among Sri Lankan P. chola sequences. It provides evidence for the presence of genetically diverged phylogenetic species in Sri Lanka closely related to the Indian taxon, and substantiates the recent taxonomic revival of the name Puntius thermalis for the Sri Lankan taxon. Further morphological studies with type specimens of Indian P. chola will be important to clarify these findings