A Morphometric Study of Phylogenetic and Ecologic Patterns in Procyonid (Mammalia: Carnivora) Endocasts

Abstract

Brain size and shape have been linked to numerous evolutionary trends, with patterns of encephalization and variation well‐studied in Carnivora. Endocasts provide a proxy for brain morphology and access to potential suites of characters, but rarely are endocast characters used in cladistic analyses. We used three‐dimensional geometric morphometrics to examine phylogenetic and ecologic patterns in the endocasts of procyonids. Endocasts of seven ingroup taxa and four outgroup taxa were digitally rendered and 21 surface landmarks were collected. We tested correspondence of ‘brain shape’ with competing morphological and molecular phylogenies of Procyonidae. In analyses incorporating all taxa there was phylogenetic signal in brain shape for both topologies, but in analyses of ingroup taxa there was phylogenetic signal in the morphological topology only. Differences in brain shape suggest that procyonids emphasized areas associated with motor control, spatial perception, and balance relative to the basal musteloid, perhaps associated with increased arboreality. In Procyonidae, areas of the brain associated with arboreal behavior are also expanded in some taxa, but greater variation of brain shape occurs.Grant Funding Source: none