Shape variability in the periotics of odontocetes (Cetacea) distributed along the Pacific coast of northern Mexico

Twenty-three species and four subspecies of odontocete belonging to five families (Delphinidae, Physeteridae, Kogiidae, Phocoenidae, and Ziphiidae) are distributed along the Pacific coast of northern Mexico. The morphological variability of these species has been studied extensively and a number of taxonomic studies have focused on cranial characteristics. The goal of this study was to describe the periotics of the odontocetes of the Pacific coast of northern Mexico and develop a taxonomic tool using descriptions of each species. We used a geometric morphometric analysis of 186 periotics housed in local and national osteological collections. Our results show the taxonomic value of periotics and a significant phylogenetic signal associated with this structure. Based on these results we present a descriptive catalog that can be used for identification purposes.