Phenotypic integration in feliform carnivores: covariation patterns and disparity in hypercarnivores versus generalists

The skeleton is a complex arrangement of anatomical structures that covary
to various degrees depending on both intrinsic and extrinsic factors.
Among the Feliformia, many species are characterized by predator
lifestyles providing a unique opportunity to investigate the impact of
highly specialised hypercarnivorous diet on phenotypic integration and
shape diversity. To do so, we compared the shape of the skull, mandible,
humerus, and femur of species in relation to their feeding strategies
(hypercarnivorous versus generalist species) and prey preference
(predators of small versus large prey) using three-dimensional geometric
morphometric techniques. Our results highlight different degrees of
morphological integration in the Feliformia depending on the functional
implication of the anatomical structure, with an overall higher
covariation of structures in hypercarnivorous species. The skull and the
forelimb are not integrated in generalist species whereas they are in
hypercarnivores. These results can potentially be explained by the
different feeding strategies of these species. Contrary to our
expectations, hypercarnivores display a higher disparity for the skull
than generalist species. This is probably due to the fact that a
specialisation toward high-meat diet could be achieved through various
phenotypes. Finally, humeri and femora display shape variations depending
on relative prey size preference. Large species feeding on large prey tend
to have robust long bones due to higher biomechanical constraints.