Does nasal echolocation influence the modularity of the mammal skull?

In vertebrates, changes in cranial modularity can evolve rapidly in response to selection. However, mammals have apparently maintained their pattern of cranial integration throughout their evolutionary history and across tremendous morphological and ecological diversity. Here, we use phylogenetic, geometric morphometric and comparative analyses to test the hypothesis that the modularity of the mammalian skull has been remodelled in rhinolophid bats due to the novel and critical function of the nasal cavity in echolocation. We predicted that nasal echolocation has resulted in the evolution of a third cranial module, the ‘nasal dome’, in addition to the braincase and rostrum modules, which are conserved across mammals. We also test for similarities in the evolution of skull shape in relation to habitat across rhinolophids. We find that, despite broad variation in the shape of the nasal dome, the integration of the rhinolophid skull is highly consistent with conserved patterns of modularit...

在脊椎动物中，颅骨模块化特征可随选择压力快速演化。然而，哺乳动物即便历经漫长演化历程与巨大的形态、生态多样性分化，仍维持了其颅骨整合的固有模式。本研究采用系统发育分析、几何形态测量学（geometric morphometrics）与比较分析方法，检验如下假说：因鼻腔在回声定位中发挥了全新且关键的功能，菊头蝠科（Rhinolophidae）蝙蝠的颅骨模块化结构已发生重塑。我们推测，鼻腔回声定位的演化使得菊头蝠科蝙蝠的颅骨演化出第三个模块化单元——鼻穹隆（nasal dome），而哺乳动物保守的颅骨模块化单元仅包含脑颅与吻部模块。此外，本研究还检验了菊头蝠科蝙蝠颅骨形状演化与栖息环境关联性的趋同特征。研究结果显示，尽管鼻穹隆的形态存在广泛变异，菊头蝠科蝙蝠的颅骨整合模式仍高度契合保守的模块化演化规律……