An island apart: Cranial endocast variation and sensory function in Tenrecomorpha

It has long been recognized that, among extant mammals, the afrotherian clade Tenrecomorpha contains an exceptional range of sensory specialists in which arboreal, fossorial, semiaquatic and possibly even echolocating species occur within a single clade. Despite their obvious interest in this regard, the sensory apparatus of these animals has not been investigated with modern techniques. Presented here is a geometric morphometric analysis of virtual endocasts of 24 tenrecomorph species (~ 69% of extant diversity) reconstructed via high-resolution uCT techniques. Utilizing linear regression and PCA analyses we identify a model including allometry, habitat, and evolutionary history as the main factors underlying shape variability. Distinct clusters in the tenrecomorph morphospace correspond to shifts within the olfactory and cortical regions of the brain, which covary with independent evolution of aquatic and fossorial behaviors. These results showcase remarkable instances of sensory convergence within the clade and provide a template for inter- and intra-clade analyses of this distinctive branch of the mammal tree.