Hyphalosaurus

Hyphalosaurus (meaning "submerged lizard") is a genus of freshwater aquatic reptile, and a major part of the Jehol Biota. It lived during the early Cretaceous period (Aptian age), about 122 million years ago. It contains two species, H. lingyuanensis and H. baitaigouensis, both from the Yixian Formation of Liaoning Province, China. It is among the best-known animals from the Jehol Biota, with thousands of fossil specimens representing all growth stages in scientific and private collections.