Bone histology as a clue in the interpretation of functional adaptations in the Thalattosuchia (Reptilia, Crocodylia)

The histological study of various bones in the families Teleosauridae and Metriorhynchidae reveals common, but also contrasting structural features of the skeleton. Both display a zonal pattern of bone tissue, suggesting a cyclic growth and an ecto-poikilothermic physiology, quite similar to those of recent crocodiles. However, the Teleosauridae exhibit no peculiar skeletal specializations related to marine life, which suggests that they had an amphibious, rather than a truly marine habitat. Conversely, the skeleton of the Metriorhynchidae displays a certain degree of structural lightening, especially obvious in their skull, but also present in their femora and ribs. This structural specialization of the skeleton, together with the supposed physiological regime of the Metriorhynchidae, had definite bearings on their body trim in water, locomotor capabilities, and activity cycles. These various topics are discussed with reference to the ecological and eco-physiological adaptations of the Thalattosuchia.