Uncovering the mosaic evolution of the carnivoran skeletal system

The diversity of vertebrate skeletons is often attributed to adaptations
to distinct ecological factors such as diet, locomotion, and sensory
environment. Although the adaptive evolution of skull, appendicular
skeleton, and vertebral column is well studied in vertebrates,
comprehensive investigations of all skeletal components simultaneously are
rarely performed. Consequently, we know little of how modes of evolution
differ among skeletal components. Here, we tested if ecological and
phylogenetic effects led to distinct modes of evolution among the cranial,
appendicular, and vertebral regions in extant carnivoran skeletons. Using
multivariate evolutionary models, we found mosaic evolution in which only
the mandible, hindlimb, and posterior (i.e., last thoracic and lumbar)
vertebrae showed evidence of adaptation towards ecological regimes whereas
the remaining skeletal components reflect clade-specific evolutionary
shifts. We hypothesize that the decoupled evolution of individual skeletal
components may have led to the origination of distinct adaptive zones and
morphologies among extant carnivoran families that reflect phylogenetic
hierarchies. Overall, our work highlights the importance of examining
multiple skeletal components simultaneously in ecomorphological analyses.
Ongoing work integrating the fossil and paleoenvironmental record will
further clarify deep-time drivers that govern carnivoran diversity we see
today and reveal the complexity of evolutionary processes in
multicomponent systems.