Cranial shape differentiation of a small, isolated community of bottlenose dolphins (Tursiops truncatus, Montagu, 1821) from Southeast Pacific.

The bottlenose dolphin (Tursiops spp., Montagu, 1821; Ehrenberg, 1833) (Delphinidae) exhibits high polymorphism worldwide, which causes the genus’ taxonomy to undergo frequent revisions. In the Southeast Pacific, ecological studies of this genus in the estuarine habitat of the Gulf of Guayaquil, Ecuador demonstrated the occurrence of a small resident community, as seen in numerous locations. Genetic research suggested that they may be a distinct lineage. In this presentation, we will show preliminary results from 3D modelling, to characterize skull shape variation between this estuarine community and other pelagic bottlenose dolphins (from the Southeast Pacific and elsewhere). We digitized 71 single point, 3 patch and 8 line 3D landmarks in a sample of 40 skulls of adult specimens from the Southeast Pacific, Northeast Atlantic and Southwest Atlantic oceans, and carried out 3D Geometric Morphometrics analyses. We discuss potential taxonomic implications of our findings, in the wider context of this diverse genus.