Do functional demands associated with locomotor habitat, diet, and activity pattern drive skull shape evolution in musteloid carnivorans?

Abstract

A major goal of evolutionary studies is to better understand how complex morphologies are related to the different functions and behaviours in which they are involved. For example, during locomotion and hunting behaviour, the head and the eyes have to stay at an appropriate level in order to reliably judge distance as well as to provide postural information. The morphology and orientation of the orbits and cranial base will have an impact on eye orientation. Consequently, variation in orbital and cranial base morphology is expected to be correlated with aspects of an animal's lifestyle. In this study, we investigate whether the shape of the skull evolves in response to the functional demands imposed by ecology and behaviour using geometric morphometric methods. We test if locomotor habitats, diet, and activity pattern influence the shape of the skull in musteloid carnivorans using (M)ANOVAs and phylogenetic (M)ANOVAs, and explore the functional correlates of morphological features in relation to locomotor habitats, diet, and activity pattern. Our results show that phylogeny, locomotion and, diet strongly influence the shape of the skull, whereas the activity pattern seems to have a weakest influence. We also show that the locomotor environment is highly integrated with foraging and feeding, which can lead to similar selective pressures and drive the evolution of skull shape in the same direction. Finally, we show similar responses to functional demands in musteloids, a super family of close related species, as are typically observed across all mammals suggesting the pervasiveness of these functional demands.

Evolution of morphological integration in the skull of Carnivora (Mammalia): Changes in Canidae lead to increased evolutionary potential of facial traits

“…; Dumont et al. ), with subsequent within‐family ecomorphological adaptations (Mattson ; Sacco and Van Valkenburgh ; Figueirido et al. ; Jones and Goswami ; Slater et al.…”

Effects of diet on cranial morphology and biting ability in musteloid mammals

“…Therefore, evolutionary shifts towards relatively higher bite forces can also occur through modification of skull shape such as increasing the size of attachment sites of the jaw adductor muscles and/or enhancing mechanical advantage of jaw closure by lengthening the input levers of the jaw adductors and/or shortening the jaw length (Radinsky, ; Santana et al ., ; Collar et al ., ; Zelditch et al ., ). Many researchers have identified significant shape differences between species with different dietary ecologies (Dumont et al ., ; Zelditch et al ., ; McLean et al ., ), but few have examined whether these shape differences also translate to bite force differences. Although some clades exhibit strong correlations between size‐corrected bite force and cranial shapes (Herrel et al ., ; Nogueira et al ., ; Dollion et al ., ), the vast majority of vertebrate clades exhibit many‐to‐one mapping of form to function where distinct cranial morphologies lead to the same feeding performance (Alfaro et al ., ; Wainwright et al ., ; Young et al ., ; Collar et al ., ; Kolmann et al ., ; Zelditch et al ., ).…”

“…In a comparative study of 31 musteloid species, Dumont et al . () found that cranial shapes significantly differed between dietary ecologies. However, whether these differences in cranial shape translate to functional differences such as estimated bite force between dietary groups remains unknown.…”

Carnivory maintains cranial dimorphism between males and females: Evidence for niche divergence in extant Musteloidea

“…Musteloids (e.g., badgers, otters, raccoons, skunks, and weasels) are a speciose and ecologically diverse clade of carnivorans (Fabre et al 2013Dumont et al 2015;Law et al 2018). Musteloids (e.g., badgers, otters, raccoons, skunks, and weasels) are a speciose and ecologically diverse clade of carnivorans (Fabre et al 2013Dumont et al 2015;Law et al 2018).…”