The mammalian order Carnivora is characterized by a broad taxonomic and ecological diversity. By using a large sample of extant species, we tested the impact of ecological factors on carnivoran skull (cranium and mandible) morphology, taking advantage of a combined geometric morphometrics and comparative method approach. We implemented several evolutionary models to account for different tempo and mode of evolution in size and shape data. These models validated the association between skull morphology and diet at the interspecific scale. The functional distinction between pinniped (aquatic) and fissiped (mostly terrestrial) taxa was found valid only in mandible shape and cranial size. High levels of morphological disparity and evolutionary rates were identified in specialized dietary groups, and positive association between rates and disparity was found for skull size. Cranium and mandible showed consistent patterns of covariation that reflect constrained functional processes, which stabilize the ecomorphological evolution of Carnivora. Aquatic adaptations allowed carnivorans to invade and persist within novel regions of the mandibular morphospace. This ecological shift did not increase morphological disparity but occurred at a faster rate than in terrestrial species. Those species exhibit a stronger level of cranio-mandibular covariation due to constraints imposed by more demanding masticatory adaptations.

中文翻译：

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食肉目头骨的宏观进化生态形态学：现存物种的适应和限制

哺乳动物目食肉目以广泛的分类和生态多样性为特征。通过使用大量现存物种样本，我们利用几何形态计量学和比较方法相结合的方法，测试了生态因素对食肉动物头骨（颅骨和下颌骨）形态的影响。我们实施了几个进化模型来解释大小和形状数据的不同速度和进化模式。这些模型在种间尺度上验证了颅骨形态与饮食之间的关联。鳍足类（水生）和裂殖类（主要是陆生）分类群之间的功能区别仅在下颌骨形状和颅骨大小方面有效。在专门的饮食组中发现了高水平的形态差异和进化率，并且发现颅骨大小的比率和差异之间存在正相关关系。头盖骨和下颌骨显示出一致的协变模式，反映了受约束的功能过程，从而稳定了食肉目的生态形态进化。水生适应使食肉动物能够侵入并在下颌形态空间的新区域内持续存在。这种生态转变并没有增加形态差异，但比陆地物种发生的速度更快。由于更苛刻的咀嚼适应所施加的限制，这些物种表现出更强的颅下颌协变水平。水生适应使食肉动物能够侵入并在下颌形态空间的新区域内持续存在。这种生态转变并没有增加形态差异，但比陆地物种发生的速度更快。由于更苛刻的咀嚼适应所施加的限制，这些物种表现出更强的颅下颌协变水平。水生适应使食肉动物能够侵入并在下颌形态空间的新区域内持续存在。这种生态转变并没有增加形态差异，但比陆地物种发生的速度更快。由于更苛刻的咀嚼适应所施加的限制，这些物种表现出更强的颅下颌协变水平。