Data from: Go big or go fish: morphological specializations in carnivorous bats

Specialized carnivory is relatively uncommon across mammals, and bats constitute one of the few groups in which this diet has evolved multiple times. While size and morphological adaptations for carnivory have been identified in other taxa, it is unclear what phenotypic traits characterize the relatively recent evolution of carnivory in bats. To address this gap, we apply geometric morphometric and phylogenetic comparative analyses to elucidate which characters are associated with ecological divergence of carnivorous bats from insectivorous ancestors, and if there is morphological convergence among independent origins of carnivory within bats, and with other carnivorous mammals.We find that carnivorous bats are larger and converged to occupy a subset of the insectivorous morphospace, characterized by skull shapes that enhance bite force at relatively wide gapes. Piscivorous bats are morphologically distinct, with cranial shapes that enable high bite force at narrow gapes, which is necessary for processing fish prey. All animal-eating species exhibit positive allometry in rostrum elongation with respect to skull size, which could allow larger bats to take relatively larger prey. The skull shapes of carnivorous bats share similarities with generalized carnivorans, but tend to be more suited for increased bite force production at the expense of gape, when compared with specialized carnivorans.

特化肉食性在哺乳类中相对罕见，而蝙蝠是少数这类食性多次独立演化的类群之一。尽管其他类群中已发现肉食性相关的体型与形态适应性，但蝙蝠肉食性较晚演化过程中所对应的表型特征仍不明确。为填补这一研究空白，本研究采用几何形态测量学（geometric morphometric）与系统发育比较分析方法，阐明肉食性蝙蝠从食虫祖先类群发生生态分化所关联的性状特征，并探究蝙蝠内部独立起源的肉食性类群之间、以及其与其他肉食性哺乳类之间是否存在形态趋同。研究发现，肉食性蝙蝠体型更大，且趋同占据了食虫类形态空间的一个子集，其头骨形态特征可在较大张口幅度下提升咬合力。食鱼蝙蝠则具有独特的形态特征，其头骨形态可在狭小张口幅度下实现高咬合力，这对处理鱼类猎物至关重要。所有食肉类蝙蝠均表现出吻突伸长相对于头骨尺寸的正异速生长模式，这或许能让体型更大的蝙蝠捕食体型相对更大的猎物。肉食性蝙蝠的头骨形态与泛化食肉目类群具有相似性，但相较于特化食肉目类群，其头骨形态更偏向于提升咬合力，而以牺牲张口幅度为代价。