Diet drove brain and dental morphological coevolution in strepsirrhine primates

Abstract

The evolution of the remarkably complex primate brain has been a topic of great interest for decades. Multiple factors have been proposed to explain the comparatively larger primate brain (relative to body mass), with recent studies indicating diet has the greatest explanatory power. Dietary specialisations also correlate with dental adaptations, providing a potential evolutionary link between brain and dental morphological evolution. However, unambiguous evidence of association between brain and dental phenotypes in primates remains elusive. Here we investigate the effect of diet on variation in primate brain and dental morphology and test whether the two anatomical systems coevolved. We focused on the primate suborder Strepsirrhini, a living primate group that occupies a very wide range of dietary niches. By making use of both geometric morphometrics and dental topographic analysis, we extend the study of brain-dental ecomorphological evolution beyond measures of size. After controlling for allometry and evolutionary relatedness, differences in brain and dental morphology were found between dietary groups, and brain and dental morphologies were found to covary. Historical trajectories of morphological diversification revealed a strong integration in the rates of brain and dental evolution and similarities in their modes of evolution. Combined, our results reveal an interplay between brain and dental ecomorphological adaptations throughout strepsirrhine evolution that can be linked to diet.

Nest attachment, rather than nest type, correlates with passerine bird brain size

“…Alternatively, significantly slower Rbmass diversification rates in passerines constructing Top suspended nests could occur if this type of nest attachment was the ancestral state (see also López‐Aguirre et al . 2022). However, we found this idea improbable because in a broad study involving all passerine families, the ancestral state of nest attachment mode was Basal , with other nest attachment forms arising independently several times in this bird order (Fang et al .…”