Mamenchisaurus (mah-MUN-chee-SAW-rus,(External Link) or spelling pronunciation /məˌmɛntʃiːˈsɔrəs/) was a plant-eating four-legged dinosaur, known for its remarkably long neck. Most species lived 145 to 150 million years ago, in the Tithonian age of the late Jurassic Period. Discoveries Mamenchisaurus was first discovered in 1952 on a highway construction site in Sichuan, China. The partial skeleton fossil was then studied, and named in 1954, by the reno… (More on Mamenchisaurus)