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Osteopygis emarginatus Cope 1868 is described from the Lower Tertiary of the Ouled Abdoun phosphate basin, Morocco, on the basis of skulls and lower jaws. Osteopygis is a cosmopolitan turtle that had a wide geographical distribution during the Late Cretaceous and Paleocene. Osteopygis emarginatus is a very conservative species which crossed the Cretaceous/Tertiary boundary without major changes.
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Hirayama et al. (2003) studied this question.
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