Ankylosaurus

Ankylosaurus (pronounced /æŋˈkɪloʊˌsɔɹəs/ or /æŋˈkaɪloʊˌsɔɹəs/, meaning 'stiffened lizard') is a genus of ankylosaurid dinosaur, containing one species, A. magniventris. Fossils of Ankylosaurus are found in geologic formations dating to the very end of the Cretaceous Period in western North America.

Although a complete skeleton has not been discovered and several other species are represented by more extensive fossil material, Ankylosaurus is often considered the archetypal armored dinosaur. Other ankylosaurids shared its well-known features, like the heavily-armored body and massive bony tail club, but Ankylosaurus was the largest member of its family.