Ankylosaurus (/ˌæŋkɪloʊˈsɔːrəs/ ANG-ki-lo-SAWR-əs or /æŋˌkaɪloʊˈsɔːrəs/ ang-KY-lo-SAWR-əs, and which means "fused 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 (between about 66.5–66 Ma ago) in western North America.
Although a complete skeleton has not been discovered and several other dinosaurs are represented by more extensive fossil material, Ankylosaurus is often considered the archetypal armored dinosaur. Other ankylosaurids shared its well-known features—the heavily armored body and massive bony tail club—but Ankylosaurus was the largest known member of the family. (see more...)