Triassic Period, 250-200 million years BP. Aplete fossil Keichoaur hui in a rectangular matrix. 171 grams, 15.5cm wide (6"). Private Bristol collection since 1980s. Property of a Ssex, UK, teacher. Keichoaur was a late-Triassic marine reptile, and a member of the Pleurosaur family, and went extinct 250 million years ago during the Triassic-Jurassic extinction event. They were specialised fish eaters, and were highly unual amongst marine reptiles in that they gave birth to live young rather than laying eggs.