石鲈科鱼类的系统发育分析兼论髭鲷属的分类地位

PHYLOGENY OF HAEMULID WITH DISCUSSION ON SYSTEMATIC POSITION OF THE GENUS HAPALOGENYS

通过线粒体16SrRNA基因部分序列分子标记,分析了石鲈科7属15种鱼的分子系统发育关系,并通过对部分种类16SrRNA基因片段的RNA二级结构的分析,对髭鲷属分类地位进行了探讨。结果表明:15种石鲈科鱼类分为3个类群,石鲈属Haemulon、Xenistius和Anisotremus属组成类群1,矶鲈属和胡椒鲷属组成类群2,髭鲷属组成类群3;在亲缘关系上类群1和类群2较近,它们与类群3相对较远;在遗传差异上,髭鲷属与其它6个属的遗传差异接近甚至超过其与外类群笛鲷科、鲷科和隆头鱼科种类的遗传差异。在NJ和MP系统发育树中,髭鲷属与外类群笛鲷科、鲷科和隆头鱼科种类聚集在一起,石鲈科鱼类未能构成单一分支类群;同时,横带髭鲷为代表的髭鲷属鱼类16SrRNA基因长度74bp的基因片段的RNA二级结构与其余石鲈科种类存在明显的结构差异。因此,研究结果支持将髭鲷属从石鲈科中独立出来形成髭鲷科Haplogeniidae的观点。

Numerous grunts of family Haemulidae occupy demersal habitats of continental and insular shelves in tropical and warm temperate areas,some of them are of great commercial value and have been cultured as significant breeds.Despite their importance,systematic statuses and specific identification of some haemulid species are still controversial.In this study,phylogenetic relationships among 15 species of haemulid fishes,representing 7 genera,were reconstructed using partial mitochondrial 16S ribosomal RNA gene sequences with maximum parsimony and neighbor-joining methods.MP and NJ phylogenetic trees both revealed that 15 grunts were divided into three clades with Clade1 composed of Pomadasys,Haemulon,Xenistius and Anisotremus,Clade 2 of Parapristipoma and Plectorhynchus,and Clade3 of Hapalogenys.Clade 1 was closer to Clade 2 rather than to Clade3,which generally congruent with those by previous morphological studies.Nevertheless,two Hapalogenys species,H.mucronatus and H.nigripinnis,were clustered with outgroup species Ocyurus chrysurus,Argyrops spinifer,and Hemigymnus melapterus,which indicated that haemulid fishes were unlikely a monophyletic group.Divergence between Hapalogenys and other six genera of grunts were closer or exceeded（0.104-0.175）than those between Hapalogenys and outgroup species in families Lutjanidae,Sparidae,Labridae（0.082-0.138）.In addition,RNA secondary structures of a 74-base 16S rRNA homologous gene fragments in representative species,including Plectorhynchus pictus,Pomadasys kaakan,Haemulon plumieri,Parapristipoma trilineatus,Hapalogenys nigripinnis were constructed and analysed to infer the taxonomic status of Hapalogenys.There were obvious differences in Hapalogenys and other species mentioned above.Hence,our results supported the hypothesis by Spring and Raasch that Hapalogenys might be upgraded to the family Haplogeniidae.