我国近海裸胸鳝属鱼类新记录种——黏裸胸鳝（Gymnothorax mucifer）形态与分子系统学研究

本研究于2020-2021年在福建省厦门市近海水产市场采集到4尾黏裸胸鳝样品，为中国大陆近海新记录种。此前，该物种仅在澳大利亚、夏威夷等地有分布记录，并被认为是蠕纹裸胸鳝同种异名。本研究对采集的黏裸胸鳝进行详细形态特征分析，结合DNA条形码COI基因进行分子鉴定及系统进化关系分析。黏裸胸鳝的主要鉴别特征：体为黄棕色，头部前端淡紫色，身体布满细长、稀疏、弥散的树枝状不规则棕色斑纹，斑纹颜色靠近尾部加深加粗，形成网格状；臀鳍边缘白色，近尾部变为一列连续白色斑点；全长为体长的1.01倍，为头长的8.00～8.39倍；上颌齿每侧8～10个，下颌齿每侧14～20个，中央齿细长，均为单行；总椎骨数为117～139，平均椎骨式为6-47-130。基于COI基因分析，黏裸胸鳝与蠕纹裸胸鳝的遗传距离为0.074，大于Herbert设定的2%(0.020)作为区分不同物种最小遗传距离，表明两者应为不同的物种。形态上，两种裸胸鳝也存在差异特征，如黏裸胸鳝的斑纹较细长、稀疏、不明显，头部前端偏淡紫色，臀鳍白色边缘近尾部断裂成系列连续白色斑点；蠕纹裸胸鳝的斑纹粗大明显、颜色较深，头部前端黄白色，臀鳍白色边缘连续...

The morphological and molecular phylogenetic studies of a new record Gymnothorax species in the coastal waters of China: Gymnothorax mucifer

In this study, four samples of Gymnothorax mucifer were collected from the fishery market of Xiamen City, Fujian Province during the year 2020 to 2021, which were newly recorded in the coastal waters of China. Previously, the species had only been recorded in Australia and Hawaii, and was considered to be a synonym of Gymnothorax kidako. Detailed morphological characteristics of four G. mucifer species were analyzed, and the molecular identifications as well as phylogenetic constructions were also carried out basing on DNA barcode COI gene in this study. The main distinguishing characteristics of G. mucifer were as follow: the colour of the body was yellowish brown, the front of the head was slightly purple, the whole body was covered with slender, sparse, irregular branch-liked brown marking and the markings became darker and thicker near the tail, forming clear net-liked patterns; the margin on the anal fin was white, and became serial pale blotches on posterior part of the tail; total length was 1.01 times of standard length and 8.00?8.39 times of head length; the maxillary teeth were 8?10 and dentary teeth were 14?20 on each side, both teeth were uniserial; the median inter maxillary teeth were slender and uniserial; the total vertebrae were 117?139 and mean vertebral formula was 6-47-130. Basing on the COI gene analysis, the genetic distance between G. mucifer and G. kidako was 0.074, which was greater than the value 2% (0.020) suggested by Herbert as minimum genetic distance value to distinguishing different species, revealing that the two species might be two independent species. Morphologically, G. mucifer could also be distinguished from G. kidako by certain external characteristic: the body markings of G. mucifer were slender, sparse and inconspicuous, the front of the head was slightly purple, and the white margin of the anal fin broke into series of pale blotches on posterior part of the tail; the markings of G. kidako were obvious and thick with darker colour, the front of the head was yellow-white, the white margin on the anal fin continuous to the tip of the tail. The results of the study provided a taxonomic basis for the systematic classification and the species list revision of the Gymnothorax fish in our country.