Cranial variation between coastal and offshore bottlenose dolphins, <i>Tursiops truncatus</i> (Cetacea: Delphinidae) in Ecuador and the Mediterranean: a three-dimensional geometric morphometric study

Abstract Skull shape analysis provides useful information on wildlife ecology and potential local adaptations. Common bottlenose dolphins (Tursiops truncatus) often differentiate between coastal offshore populations worldwide, skull analyses can be particularly in this context. Here we quantify variation from the Gulf of Guayaquil (Ecuador) Mediterranean Sea, compared to specimens multiple oceans. We analysed differences using 3D models museum through geometric morphometrics (3DGM). Two complementary landmark approaches included single-point semi-landmarks homologous features, as well pseudo-landmarks placed automatically. Results show distinction both specimens. Offshore showed little differentiation distinct locations. patterns mostly diverged length rostrum, ascending processes maxilla, pterygoids, occipital bones. However, differed direction change those features were also morphologically distinct. Our results are consistent with data site fidelity social structure populations. changes suggest divergent feeding sound production drivers, probably specific environment each community.