Simultaneous integration and modularity underlie the exceptional body shape diversification of characiform fishes
Simultaneous integration and modularity underlie the exceptional body shape diversification of characiform fishes
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DOI：
10.1093/evolut/qpac070
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发表时间：
2023-03-01
期刊：
影响因子：
3.3
通讯作者：
Sidlauskas，Brian L.
中科院分区：
文献类型：
--
作者：
Burns，Michael D.;Collyer，Michael L.;Sidlauskas，Brian L.
进化生物学长期以来一直在努力理解为什么一些谱系异常多样化，而另一些则不是。大多数研究集中在外部因素如何促进多元化动态的差异，但一个支系的内在模块化和集成性也可以催化或限制其进化。在这里，我们结合几何形态计量学、系统发育比较方法和协方差可视化来推断轮形目鱼类的身体平面中存在不同的模块，这是一种生态形态多样化的鱼类辐射。较强的协方差显示了一个颅骨模块，更细微的模式支持将颅后分为前(尾部)和后(尾部)模块。我们发现了颅骨和颅后地标之间的实质性协变，表明整个身体的进化整合是扁平体型和梭形体型之间的谱系转换。一种新的矩阵细分方法揭示了模块内和模块间的协变对特征形态空间的总体特征结构有很大贡献，并且这两种现象都导致了特征谱系之间在生物学上的重要分歧。头骨和后颅骨之间的功能整合似乎使血统能够优化其身体的长宽比，以便于运动，而头部、身体和尾巴的独立变化能力可能会减轻对不同饮食和水文制度的适应。这些结果加强了一个日益增长的共识，即模块化和一体化协同作用，促进多样化。
Evolutionary biology has long striven to understand why some lineages diversify exceptionally while others do not. Most studies have focused on how extrinsic factors can promote differences in diversification dynamics, but a clade’s intrinsic modularity and integration can also catalyze or restrict its evolution. Here, we integrate geometric morphometrics, phylogenetic comparative methods and visualizations of covariance to infer the presence of distinct modules in the body plan of Characiformes, an ecomorphologically diverse fish radiation. Strong covariances reveal a cranial module, and more subtle patterns support a statistically significant subdivision of the postcranium into anterior (precaudal) and posterior (caudal) modules. We uncover substantial covariation among cranial and postcranial landmarks, indicating body-wide evolutionary integration as lineages transition between compressiform and fusiform body shapes. A novel method of matrix subdivision reveals that within- and among-module covariation contributes substantially to the overall eigenstructure of characiform morphospace, and that both phenomena led to biologically important divergence among characiform lineages. Functional integration between the cranium and post-cranial skeleton appears to have allowed lineages to optimize the aspect ratio of their bodies for locomotion, while the capacity for independent change in the head, body and tail likely eased adaptation to diverse dietary and hydrological regimes. These results reinforce a growing consensus that modularity and integration synergize to promote diversification.