Based on their morphological characters, the butterfish, genus Pampus (Family: Stromateidae) is classified into three sympatric species: Pampus argenteus, P. nozawae and P. Chinese. However, their taxonomic status remains ambiguous due to the great morphological similarities among three species. Both morphological and biochemical methods, thus, are utilized to verify the classification of species and to determine biochemical markers. It is found only slight morphological differences in the meristic and morphometric characters among three species. On account of the genetic distinction verified by the present biochemical genetic study, Pampus spp. are recognized as three separate biological species. The morphological similarity and highly genetic differentiation between P. nozawae and P....[ Read more ]

Based on their morphological characters, the butterfish, genus Pampus (Family: Stromateidae) is classified into three sympatric species: Pampus argenteus, P. nozawae and P. Chinese. However, their taxonomic status remains ambiguous due to the great morphological similarities among three species. Both morphological and biochemical methods, thus, are utilized to verify the classification of species and to determine biochemical markers. It is found only slight morphological differences in the meristic and morphometric characters among three species. On account of the genetic distinction verified by the present biochemical genetic study, Pampus spp. are recognized as three separate biological species. The morphological similarity and highly genetic differentiation between P. nozawae and P. argenteeus imply that they are two sibling species; Hk1, Hk2, Sod1 and Sod2 with the alternatively fixed alleles are found as diagnostic loci to distinguish them. G3pdhl and Pep-B2 with the significant allelic differences are potential biochemical genetic markers to differentiate P. nozawae and P. Chinese which are genetically closed (Nei's genetic distance=0.028), both of which greatly diverge from P. argenteus. The discrepancy between morphology resemblance and genetic divergence among Pampus species suggests the different evolutionary rates of their morphology and proteins. Our electrophoretic data also show a high level of genetic variability of Pampus species in Hong Kong waters. Nei's divergence time indicates that the three species splitted from the common ancestor 1.57 million years ago. The speciation of these species is considered.