Data from: Patterns of morphological integration in the appendicular skeleton of mammalian carnivores

We investigated patterns of evolutionary integration in the appendicular skeleton of mammalian carnivores. The findings are discussed in relation to performance selection in terms of organismal function as a potential mechanism underlying integration. Interspecific shape covariation was quantified by 2B-PLS analysis of 3D landmark data within a phylogenetic context. Specifically, we compared pairs of anatomically connected bones (within-limbs) and pairs of both serially homologous and functional equivalent bones (between-limbs). The statistical results of all the comparisons suggest that the carnivoran appendicular skeleton is highly integrated. Strikingly, the main shape covariation relates to bone robustness in all cases. A bootstrap test specifically developed to compare the degree of integration between specialized cursorial taxa (i.e., those whose forelimbs are primarily involved in locomotion) and non-cursorial species (i.e., those whose forelimbs are involved in more functions than their hind limb) showed that cursors have a more integrated appendicular skeleton than non-cursors. The findings demonstrate that natural selection can influence the pattern and degree of morphological integration by increasing the degree of bone shape covariation in parallel to ecological specialization.

本研究探究了食肉目哺乳动物（mammalian carnivores）附肢骨骼（appendicular skeleton）的进化整合模式。研究结果围绕作为整合潜在机制的机体功能（organismal function）层面的性能选择（performance selection）展开讨论。我们通过在系统发育框架（phylogenetic context）下对三维地标数据（3D landmark data）开展2B-PLS分析，量化了种间形状协变（interspecific shape covariation）程度。具体而言，我们对比了两类骨骼配对：一类为解剖学上相连的骨骼（anatomically connected bones，即同肢体内部的骨骼），另一类为系列同源骨骼与功能等效骨骼（serially homologous and functional equivalent bones，即跨肢体的骨骼）。所有对比的统计结果均表明，食肉目动物的附肢骨骼具有高度的整合性。值得注意的是，所有案例中的核心形状协变均与骨骼粗壮度相关。一项专门用于对比特化奔跑类群（cursorial taxa，即前肢主要用于运动的类群）与非奔跑类群（non-cursorial species，即前肢承担的功能多于后肢的物种）之间整合程度的自助法检验（bootstrap test）结果显示，奔跑类群的附肢骨骼整合程度高于非奔跑类群。本研究结果证实，自然选择可通过提升骨骼形状协变程度，以同步于生态特化（ecological specialization）的方式，影响形态整合（morphological integration）的模式与程度。