Morphometric and isozyme confirmation for species level divergence between Puntius dorsalis (Pisces: Cyprinidae) and its presumed red-fin variety in Sri Lanka

Abstract

Isozyme and morphological variation provide evidence for species-level divergence between Puntius dorsalis and the red-fin variety, presumed to be conspecific to P. dorsalis, thus warrant the recognition of the P. dorsalis like red-fin variety in Sri Lanka as a separate phylogenetic taxon, hitherto undescribed. Idh, Mdh-1 and Pgm isozymes display fixed allelic differences between the two varieties indicating reproductive isolation and species-level divergence. In addition to the presence of 3½ transverse scale rows above lateral line (vs. 4½ in P. dorsalis) which is a distinctive autaphomorphy, the snout is significantly longer in the red-fin variety (30.3%HL vs. 22.6%HL of P. dorsalis).

Keywords

• biological species
• fixed alleles
• phenotypic divergence
• Puntius dorsalis
• reproductive isolation