   ankylosaurus (  or  , 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 66.5â66 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 featuresâthe heavily armored body and massive bony tail clubâbut ankylosaurus was the largest known member of the family. ==description== thumb|left|estimated size of ankylosaurus compared to a human. ankylosaurus was a large animal by modern standards, estimated at lengths of  and weighing up to . however, following a significant redescription of the fossils in 2004, a much smaller size has been suggested, based on the largest known skull, at  long and  wide, the whole animal was estimated at  long,  wide and  tall at the hip. the body shape was low-slung and quite wide. it was quadrupedal, with the hind limbs longer than the forelimbs. although its feet are still unknown, comparisons with other ankylosaurs suggest ankylosaurus probably had five toes on each foot. the skull was low and triangular in shape, wider than it was long. like other ankylosaurs, ankylosaurus was herbivorous, with small, leaf-shaped teeth suitable for cropping vegetation. these teeth were smaller, relative to the body size, than in any other ankylosaurid species. ankylosaurus did not share the grinding tooth batteries of the contemporaneous ceratopsid and hadrosaurid dinosaurs, indicating that very little chewing occurred. bones in the skull and other parts of the body were fused, increasing their strength. ===armor=== thumb|left|osteoderms the most obvious f
Ankylosaurids Cretaceous_dinosaurs Dinosaurs_of_North_America