Study On Molecular Phylogeny Of Salangidae (Osmeriformes)

Noodle-fishes (Osmeriformes:Salangidae) are important commercial fishery species. However, their phylogenetic relationships are still unresolved and the taxonomy at the genus or species level has been disputed. This study examined the genus-level phylogenetic relationships of salangid fishes using four mitochondrial genes (12S and 16S ribosome RNA gene, cytochrome c oxidase subunit I gene and NADH dehydrogenase subunit 1 gene) and seven nuclear genes (28S ribosomal RNA gene, recombination activating gene 1, ectodermal-neural cortex 1-like protein gene, RNF213 gene, glycosyltransferase gene, SH3 and PX domain-containing 3-like protein gene, Zic family member 1 gene). Integrating the results of molecular phylogenetic analyses in this study with morphological and molecular evidences from previously published studies, we discussed taxonomic status of noodle-fishes at the genus or species level.The phylogenetic analyses based on the four mitochondrial genes showed that:1) the salangids is a monophyletic group; 2) Protosalanx chinensis and Neosalanx anderssoni are sister gourps; 3) two monophyletic clades, 'Neosalanx brevirostris-tangkahkeii-taihuensis-pseudotaihuensis complex' and 'N. jordani-oligodontis complex' are revealed, but the species within the two clades can not be distinguished; 4) Hemisalanx brachyrostralis and Salanx cuvieri are sister groups, and these two species together formed the sister group of S. ariakensis; 5) Leucosoma is a valid genus located at the basal position of Salangidae. However, analysis on the mitochondrial genes could not confidently decide the phylogenetic position of the genus Salangichthys.The phylogenetic analyses based on the seven nuclear genes confirmed the main conclusions from the study on mitochondrial genes:1) the monphyly of Salangidae; 2) the monophyletic 'N. brevirostris-tangkahkeii-taihuensis-pseudotaihuensis complex' and 'N. jordani-oligodontis complex'with undistinguishable interspecies relationship within the species complex. Moreover, the analyses on nuclear genes resolved the confused problem left by the analyses on mitochondrial genes:1) the family Salangidae could be divided into two clades, i.e. the'Protosalanx+Neosalanx +Salangichthys ishikawae' and the 'Hemisalanx + Salanx + Leucosoma + Salangichthys microdon'groups; 2) Salangichthys ishikawae and Salangichthys microdon occupy the basal positions of the above two groups, respectively.lintegrating the results from mitochondrial and nuclear genes, we conclude that 1) Salangidae is a monophyletic group; 2) Salangidae could be divided into subfamily Protosalanginae (the Protosalanx + Neosalanx + Salangichthys ishikawae'group) and subfamily Salanginae (the 'Hemisalanx + Salanx + Leucosoma + Salangichthys microdon'group); 3) the genus Hemisalanx is invalid, species of Hemisalanx should be put in the genus Salanx; 4) Salangichthys ishikawae should be put in a new genus; 5) Leucosoma is a valid genus; 6) Neosalanx anderssoni should be reclassified as Protosalanx anderssoni, belonging to the genus Protosalanx; 7) Neosalanx tangkahkeii, N. taihuensis and N. pseudotaihuensis are synonyms of N. brevirostris; 8) Neosalanx oligodontis and N. reganius are synonyms of N. jordani.