New data on the morphology and systematic position of the sea turtle Allopleuron qazaqstanense Karl et al. from the Middle Eocene of Kazakhstan

A new specimen of the sea turtle Allopleuron qazaqstanense Karl et al., 2012 is described. The material includes skeletal elements previously unknown for this taxon and comes from the Shorym Formation of the Kuyulus locality (Kazakhstan, Mangystau Region; Bartonian, Paleogene). Comparative analysis involving other cheloniid taxa has shown that A. qazaqstanense should not be assigned to the genus Allopleuron ; it is rather closer to Eocene Eochelone brabantica and some Oligocene cheloniids. The similarity of Allopleuron qazaqstanense to Late Cretaceous Allopleuron hofmanni results from convergence caused by similar adaptations to the pelagic lifestyle.