嘉陵江不同江段蛇的形态差异比较

为探讨嘉陵江不同江段蛇群体的形态表型特征及其差异性,实验对采自嘉陵江上游、中游和下游共120尾样本进行了传统形态测量和地标点几何形态学测量分析。形态分析结果发现,嘉陵江不同江段蛇群体间形态表型存在显著差异。差异主要集中于头部、鳍和尾柄;其中上游群体的蛇最为纤长(叉长、胸腹距、躯干距最大),眼间距、背鳍基长、头高和口角须长也最长;中游群体的胸鳍、腹鳍、尾鳍最长,尾柄也最为粗壮(尾柄宽,尾柄高最大),头长、体宽、胸鳍前距最大;下游群体的肛臀距和头宽最大。主成分分析结果发现,无法有效将不同江段蛇群体区分。研究表明,不同江段蛇群体形态表型差异均属于种内差异,这些表型差异可能是蛇对嘉陵江不同江段环境(如流速、水温、饵料类型)多样性的适应性表现。

Comparison of morphological differences of Saurogobio dabryi in different reaches of Jialing River

This research was conducted to explore the morphological characteristics and difference of Saurogobio dabryi in different river sections of Jialing River. A total of 120 samples collected from upstream, midstream and downstream of Jialing River was analyzed, using the multivariate morphometric method and the landmark-based geometric morphometric method. The morphometric analysis illustrated that there were significant differences among populations of S.dabryi in different river sections. The morphological variations of the three population were mainly observed on the head, fin and caudal peduncle.The body of S.dabryi in the upstream group was the slenderest. Besides that, the fork length, length between pectoral fin and ventral fin , trunk length, the inter-orbital width, dorsal fin coxal length, head depth and beard length in this group were the largest.The midstream group of S.dabry had the longest pectoral fin, ventral fin and caudal fin, the strongest caudal peduncle, the largest of the width of caudal stalk , the depth of caudal stalk., the longest head, the widest body and the largest length between pectoral fin and rhynchodaeum. For S.dabry in the downstream, the length between anus and anal fin and head width of the lower reaches were the largest. However, the scatter diagram of relative warp scores analysis showed that S. dabryi population from different river segments of Jialing River cannot be distinguished.The variation coefficient of morphometric characters showed that the phenotypic differences of S. dabryi in the three river segments were intraspecific. We speculated that the morphological variations of S.dabryi in Jialing River should be the result of adaptive evolution to the diverse environments in Jialing River, such as the flow rate, water temperatures, and food types.