Subadult Keichousaurus fossil, the animal is about 13.5 cm long (without bending). The general situation is dorsal type. The details are clear. The white line is quartz line. No reserve price! Keichousaurus (key-cho-saurus) is a genus of marine reptile in the pachypleurosaur family which went extinct at the close of the Triassic in the Triassic-Jurassic extinction event. The name derives from Kweichow (now Guizhou Province) in China where the first fossil specimen was discovered in 1957. They are among the most common sauropterygian fossils recovered and are often found as nearly complete, articulated skeletons, making them popular among collectors.