为探讨中国鲻科鱼类的分类地位,对采自中国8省27个地点的7种鲻科鱼类226个样本的40项测量数据进行了聚类、主成分与判别函数分析;测定了其中57个样本的标准条形码序列,结合Genbank下载的9种鱼类27条序列,构建基于K2P模型的邻接树,并进行遗传距离的计算和ABGD分析.结果发现,在形态方面,不同物种在主成分及判别函数散点图中重叠部分较大,表明对鲻科鱼类的鉴定不能仅依据单一的量度特征.在分子方面,14种鱼类聚类成12个明显的分支,分支间平均遗传距离17.14％(7.26％ ～ 23.94％),约为分支内平均遗传距离0.24％(0 ～ 1.5％)的71倍.其中,Liza sp.A、鮻(Liza haematocheila)、大鳞鮻(Liza macrolepis)、绿背鮻(Liza subviridis)、粒唇鲻(Crenimugil crenilabis)、黄鲻(Ellochelon vaigiensis)、鲻(Mugil cephalus)、帕氏凡鲻(Moolgardapera)各自独立成支,支持其物种有效性.灰鳍鮻(Liza melinopterus)、棱鮻(Liza affinis、长鳍莫鲻(Moolgarda cunnesius)、圆吻凡鲻(Valamugil seheli、Liza sp.B、Liza sp.C出现混杂.推测Genebank下载的灰鳍鮻LizamelY.LeiZ1隶属棱鮻,Liza sp.B与Liza sp.C是同一物种,圆吻凡鲻及长鳍莫鲻为同种异名,但要排除其中出现杂交的可能则需结合核基因的进一步分析.鲻分成了2组,组间平均遗传距离2.44％约为组内平均遗传距离0.08％的31倍,高于一般物种的种内遗传距离(2％),表明存在隐藏的多样性.综上所述,鲻科鱼类外部形态保守,需结合DNA条形码分析提高鉴定的准确性.%The mullet family (Mugilidae) are worldwide economically important marine fishes widely distributed in tropical,subtropical and temperate coastal waters.In recent years wild resource of mullets has been decreasing,and demanding for efficient measures to be taken for better management and sustainable exploitation is urgent.Although correct identification of species is essential for the performance of marine ecological and resources research,the insufficient morphological diagnostic characters in the mullets make it easy to be misidentified at species level.In present study,a set of 226 specimens from 7 Mugilid species collected from 27 locations in 8 provinces along coastal waters of China were subject to morphometric measurements (including 40 phenotypic charaters) and subsequent dendrogram,principal component factor and discriminant analyses.Meanwhile the partial mitochondrial cytochrome C oxidase subunit Ⅰ gene (COI) of 57 specimens from 7 Mugilid species and 27 sequences of 9 Mugilid species downloaded from GenBank were combined to conduct DNA barcoding analysis.The results were as following:morphologically Valamugil seheli,Liza affinis and Mugil cephalus were more similar,and Liza melinoptera was significantly different from the remaining species.The trunk features of Liza affinis,Mugil cephalus were more divergent from other fishes.Liza haematocheila,Valamugil seheli,Liza macrolepis,Liza affinis,Mugil cephalus were highly overlapped in the scatterplot of component factor score and discriminant scores of measurement parameters,thus these 5 species cannot be correctly differentiated by any single phenotypic feature.DNA barcodes indicated the presence of 12 distinct mitochondrial clades in 84 sequences of 14 species,and the average genetic distance among clades (17.14％,ranging from 7.26％ to 23.94％) was approximately 71-fold of the average genetic distance within clade (0.24％,ranging from 0％ to 1.5％),corresponding to 12 assumed species when the value of prior intraspecific divergence was greater than 2.15％.Of which Liza sp.A,Liza haematocheila,Liza macrolepis,Liza subviridis,Crenimugil crenilabis,Ellochelon vaigiensis,Mugil cephalus,Moolgarda perusii,formed independent clades respectively,conforming their species status.As the sequences of Liza melinoptera,Liza affinis,Liza sp.C,Liza sp.B,Moolgarda cunnesius and Valamugil seheli were mixed in 4 clades,according to the intra-and inter-species divergence (2％ of divergence or the 10 × rule) for COI gene was reported in many research findings in fish species,LizamelY.LeiZ1 might belong to Liza affinis,Liza sp.B and Liza sp.C should be the same species,and Moolgarda cunnesius and Valamugil seheli were synonyms,however nuclear markers should be used to study more specimens of these species to rule out the possibility of hybridization in these speculations.Additionally,the genetic distance (2.44％) between two subclades was approximately 31-fold of the average genetic distances(0.08％) within subclades revealed 2 genetically well-segregated groups within Mugil cephalus.In conclusion,the conservative morphological characters of the mullets may result in misidentification of the studied organism,DNA barcoding based on the mitochondrial COI gene sequences could improve the accuracy of their identification.
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