Key Insights from 3D Periotic Morphology in Odontocete Taxonomy

MILANO, VIVIANA NATALIA; VRDOLJAK, JUAN; BUONO, MÓNICA ROMINA; GAETÁN, CARLOS MAXIMILIANO; GRANDI, MARÍA FLORENCIA

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2025

0024-4066

Hearing is essential for odontocete ecology, supporting navigation, prey hunting, communication, and mother-calf bonding. This study examines morphological variation in the periotic bone, focusing on its taxonomic value, phylogenetic signal, and the influence of ecological factors on its evolution. Using photogrammetry and 3D geometric morphometrics, we analyzed 95 periotic bones from 32 species across five families (Delphinidae, Pontoporiidae, Phocoenidae, Ziphiidae, and Physeteridae). The specimens were mainly sourced from three osteological collections in Argentina, covering a wide range of odontocete taxa. We assessed the association and differentiation between families based on periotic shape, estimated the phylogenetic signal, and evaluated the influence of ecological variables on shape variation. Our results revealed clear differences between odontocete families, with a shared periotic morphotype for ziphiids and physeterids and another distinct periotic morphotype grouping of Delphinidae, Pontoporiidae, and Phocoenidae. Phylogenetic analyses showed a strong phylogenetic signal in periotic morphology, while ecological factors such as diet, habitat, diving ecology, and biosonar types were identified as key influences on its evolution. Overall, periotic shape reflects both phylogenetic history and ecological adaptations, offering significant taxonomic value by enabling clear species differentiation.