几何形态测量法结合Micro CT扫描对两水系花斑裸鲤的形态分析

MORPHOLOGICAL ANALYSIS USED BY GEOMETRIC MORPHOMETRICS COMBINED WITH MICRO CT AMONG GYMNOCYPRIS ECKLONI IN TWO DRAINAGE(TELEOSTEI: CYPRINIDAE)

研究采用现代几何形态测量法并结合Micro CT扫描技术对两水系(黄河上游与柴达木水系格尔木河)花斑裸鲤(Gymnocypris eckloni Herzenstein)的形态进行定量分析,讨论两水系花斑裸鲤是否存在先前研究未能发现的形态差异。结果显示:花斑裸鲤的两个地理种群在基于其头部形态轮廓二维坐标的主成分分析和判别分析的结果均聚在一起,这与之前文献记载的两水系花斑裸鲤的形态学特征相一致,并且对两水系花斑裸鲤进行的典型变量分析也同样支持这一结果;对花斑裸鲤两个地理种群背鳍支鳍骨插入椎骨间的相对位置这一形态特征进行卡方检验,结果表明在骨骼这一更具分类学意义的形态特征上表现出显著性差异。通过对花斑裸鲤两个地理种群的几何形态与Micro CT扫描,准确定量地分析了两水系花斑裸鲤形态上的异同,为正确评价两水系花斑裸鲤真实的演化关系奠定了形态学基础。

Gymnocypris eckloni is widely distributed in the Yellow River and Qaidam River in the northeast of the Qinghai-Tibet Plateau, China. Inconsistence between morphology and phylogenetics was observed in two different drainage G. eckloni. On this basis, we speculated that the first was the morphological convergence caused by the similar ecological pressure of the two water systems, and the second was the traditional measurement method, which makes some subtle morphological features undiscovered. Hence, the combination of geometric morphometrics and Micro CT revealed the phenotypic difference among G. eckloni of two water systems. The structure of G. eckloni’s head was almost identical between two drainages, demonstrating a significant difference in their bone structure. The divergence between head morphology and molecular data were presumably attributed to one reason. It may be that the morphological convergence caused by the similar ecological environment of the two river systems misled the taxonomic status of Gymnocypris eckloni of two water systems. The current study has laid a morphology foundation for correctly evaluating the real relationship between Gymnocypris eckloni of two water systems, and suggest that bone is an accurate standard for taxonomic classification in schizothoracin fishes. More molecular markers are required for further research to uncover the evolutionary pattern of G. eckloni from different geographic distribution.