GEOGRAPHIC-VARIATION IN SKULL MORPHOLOGY OF THE GREEN TURTLE, CHELONIA-MYDAS, WITH A TAXONOMIC DISCUSSION

This study analyzes the geographic variation of skull morphology in the green turtle, Chelonia mydas, including the eastern Pacific population sometimes recognized as C. agassizii. One hundred and forty-five skulls from six nesting sites (Comoros, Seychelles, Ogasawara [Japan], Galapagos [Ecuador], Tortuguero [Costa Rica], and Guyana) were measured. Samples from Comoros, Seychelles, and Guyana were greater in absolute skull length than those from Ogasawara, Tortuguero, and Galapagos. Discriminant analyses showed that four of the six local samples could be completely or nearly completely classified correctly. Comoros and Seychelles samples were not discriminated. The Galapagos sample was completely separated from other samples by a canonical discriminant analysis, and this result indicates distinctness of the eastern Pacific population. The Galapagos sample, however, was not differentiated from the others by any character dimension relative to skull length. From these results, we support the recognition of the eastern Pacific population as a distinct subspecies, C. mydas agassizii, but not as a distinct species.