Keichousaurus Fossil
Size: Measures approx. 43cm x 29cm x 5cm
Keichousaurus is a genus of marine reptile in the pachypleurosaur family which went extinct at the close of the Triassic (200 - 250 million years ago) in the Triassic-Jurassic extinction event. The name derives from Kweichow in China where the first fossil specimen was discovered in 1957.
Keichousaurus, like all sauropterygians, was highly adapted to the aquatic environment. The pointed head and sharp teeth in this genus indicate that they were fish-eaters, while some recovered specimens feature an especially developed ulna indicating they may have spent some time on land or in marshes. Additional fossil evidence suggests female Keichousaurus had a mobile pelvis to give birth to live young rather than laying eggs.
This fossil is distinguished by its broad ulna which makes it unlike other European genera. The broad ulna increased the surface area of the forelimbs, making it more effective in locomotion. The movement of Keichousaurus probably resembled the "underwater flight" that plesiosaurs employed. The flattened forelimbs would likely have acted as hydrofoils. Interestingly, lateral transverse processes of the anterior caudal vertebrae show that powerful muscles enabled the tail to beat or at least undulate from side to side. The combination of powerful limbs and tail would have made Keichousaurus an adept and maneuverable predator.