Ecomorphology of Carnivora challenges convergent evolution

Abstract

Convergent evolution is often reported in the mammalian order Carnivora. Their adaptations to particularly demanding feeding habits such as hypercarnivory and durophagy (consumption of tough food) appear to favour morphological similarities between distantly related species, especially in the skull. However, phylogenetic effect in phenotypic data might obscure such a pattern. We first validated the hypotheses that extant hypercarnivorous and durophagous large carnivorans converge in mandibular shape and form (size and shape). Hypercarnivores generally exhibit smaller volumes of the multidimensional shape and form space than their sister taxa, but this pattern is significantly different from random expectation only when hunting behaviour categorisations are taken into account. Durophages share areas of themorphospace, but this seems to be due to factors of contingency. Carnivorans that hunt in pack exhibit incomplete convergence while even stronger similarities occur in the mandible shape of solitary hunters due to the high functional demands in killing the prey. We identified a stronger phylogenetic signal in mandibular shape than in size. The quantification of evolutionary rates of changes suggests that mandible shape of solitary hunters evolved slowly when compared with other carnivorans. These results consistently indicate that the need for a strong bite force and robust mandible override sheer phylogenetic effect in solitary hunters