Department of Life Sciences, Imperial College London, Ascot, UK.
Marine Research and Conservation Department, Investigación Tiburones México A.C, La Paz, Mexico.
J Morphol. 2023 Aug;284(8):e21608. doi: 10.1002/jmor.21608.
The central tenet of ecomorphology links ecological and morphological variation through the process of selection. Traditionally used to rationalise morphological differences between taxa, an ecomorphological approach is increasingly being utilised to study morphological differences expressed through ontogeny. Elasmobranchii (sharks, rays and skates) is one clade in which such ontogenetic shifts in body form have been reported. Such studies are limited to a relatively small proportion of total elasmobranch ecological and morphological diversity, and questions remain regarding the extent to which ecological selection are driving observed morphometric trends. In this study, we report ontogenetic growth trajectories obtained via traditional linear morphometrics from a large data set of the brown smoothhound shark (Mustelus henlei). We consider various morphological structures including the caudal, dorsal and pectoral fins, as well as several girth measurements. We use an ecomorphological approach to infer the broad ecological characteristics of this population and refine understanding of the selective forces underlying the evolution of specific morphological structures. We suggest that observed scaling trends in M. henlei are inconsistent with migratory behaviour, but do not contradict a putative trophic niche shift. We also highlight the role of predation pressure and sex-based ecological differences in driving observed trends in morphometry, a factor which has previously been neglected when considering the evolution of body form in sharks.
生态形态学的中心原则是通过选择过程将生态和形态变化联系起来。传统上，生态形态学方法用于合理化分类群之间的形态差异，而越来越多地用于研究通过个体发育表达的形态差异。Elasmobranchii（鲨鱼、鳐鱼和魟鱼）是已经报道过这种身体形态在个体发育过程中发生变化的一个分支。此类研究仅限于Elasmobranchii 生态和形态多样性的一小部分，关于生态选择在多大程度上推动观察到的形态趋势仍存在疑问。在这项研究中，我们报告了通过传统线性形态计量学从大量棕黄真鲨（Mustelus henlei）数据集中获得的个体发育生长轨迹。我们考虑了各种形态结构，包括尾鳍、背鳍和胸鳍，以及几个周长测量。我们采用生态形态学方法来推断该种群的广泛生态特征，并深入了解特定形态结构进化背后的选择压力。我们认为，观察到的 M. henlei 中的比例趋势与迁移行为不一致，但与假定的营养生态位变化并不矛盾。我们还强调了捕食压力和基于性别的生态差异在推动形态计量学中观察到的趋势方面的作用，这一因素在考虑鲨鱼身体形态进化时以前被忽视了。
