PHYLOGENETIC RELATIONSHIPS OF NOODLE-FISHES (OSMERIFORMES: SALANGIDAE) BASED ON FOUR MITOCHONDRIAL GENES

Noodle-fishes (Osmeriformes: Salangidae) are important commercial fishery species in China and other Asian countries. Although these species are common in fresh water, estuarine and coastal habitats in East Asia, the phylogenetic relationships of noodle-fishes are still unresolved and the taxonomy at the genus or species level has been disputed. To elucidate the genus-level phylogenetic relationships of salangid fishes, partial sequences of mitochondrial 12S/16S ribosome RNA and cytochrome c oxidase subunit Ⅰ(COⅠ) genes and complete sequences of NADH dehy-drogenase subunit 1 gene were used in this present study. Phylogenetic relationships were constructed based on the combined data set of these 4 genes with 2464 bp after alignment, among which 788 sites were variable, and 723 sites were informative. Maximum Likelyhood and Bayesian methods were employed for phylogenetics analysis. Maximum Likelyhood and Bayesian analyses yielded same topology of trees. Results showed that the salangids was a mono-phyletic group. The genus Leucosoma occupied a basal position of the reconstructed Salangidae phylogeny. Two mo-nophyletic subgroups, Protosalanx + Neosalanx and Hemisalanx + Salanx were also revealed. Within Protosalanx + Neosalanx subgroup, three primitive lineage were found: (1) Protosalanx chinensis and Neosalanx anderssoni; (2) N. brevirostris-tangkahkeii-taihuensis-pseudotaihuensis complex; (3) N. jordani-oligodontis complex. The inter-specific phylogenetic relationships within N. brevirostris-tangkahkeii-taihuensis-pseudotaihuensis complex and N. jordani - oligodontis complex couldnt be clarified on the phylogeny tree. Moreover, inter-specific genetic distances were 00.19% for N. brevirostris-tangkahkeii-taihuensis-pseudotaihuensis complex and 0% for N. jordani-oligodontis com-plex based on partial sequences of mitochondrial COⅠgene. Within Hemisalanx + Salanx subgroup, Hemisalanx brachyrostralis and Salanx cuvieri were sister groups, and these two species together formed the sister group of S. ari-akensis. However, the systematic position of Salangichthys was still unresolved. Integrating findings in this study with morphological and molecular evidences from previously published studies, taxonomic status of noodle-fishes at the genus and species level were discussed detailedly. We concluded that Neosalanx anderssoni should be reclassified as Protosalanx anderssoni, belonging to the genus Protosalanx; Neosalanx tangkahkeii, N. taihuensis and N. pseuditai-huensis might be the synonyms of N. brevirostris; Neosalanx oligodontis and N. reganius are probably the synonyms of N. jordani; Hemisalanx prognathus would be the synonyms of H. brachyrostralis; Hemisalanx is invalid, so Hemisalanx brachyrostralis should be put in the genus Salanx; Leucosoma is a valid genus located at the basal position of Salangi-dae. Further researches on the phylogenetic position of Salangichthys are still needed.