Morphology of hybrid marine turtles Caretta caretta x Chelonia mydas

Abstract

We report on Caretta caretta x Chelonia mydas hybrid hatchlings that emerged from successive nests laid by a female Loggerhead Turtle (C. caretta) at Mon Repos, south-east Queensland, during the 1990–91 breeding season. We provide details of the parent female’s breeding history, which includes multiple paternity and genetic confirmation of her hybrid offspring. Three hybrid hatchlings were raised in captivity to assess whether scalation could be used to identify hybrid turtles in field studies. One captive hybrid died at 29 years of age, allowing an assessment of its reproductive status and examination of its skeletal anatomy. Two of the captive individuals were determined to be infertile. The reproductive status of the third individual was not determined. The external and skeletal morphology of the hybrids is discussed and illustrated. We show that atypical symmetrical scalation is diagnostic for C. caretta x C. mydas hybrids, as are various buccal and skeletal characters.