Ankylosaurus - Meaning : stiff lizard 

Ankylosaurus (pronounced an-KIE-loh-sore-us) is a genus of ankylosaurid dinosaur, containing one species.

Ankylosaurids shared its well-known features, like the heavily-armoured body and massive bony tail club, but Ankylosaurus was the largest member of its family, approximately the size of a large rhinoceros. It had an estimated length of 9 metres (30 ft.) and up to 1.5 metres (5 ft) wide and about 1.7 metres (67 in) high at the hip. The body shape was low-slung and very wide. Ankylosaurus was quadrupedal, with the hindlimbs longer than the forelimbs.

Although its feet are still unknown to science, 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. The largest known skull measures 64.5 centimetres (25 in) long and 74.5 cm (29 in) wide.

Ankylosaurus was herbivourous, with very small, leaf-shaped teeth suitable for cropping vegetation. 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 to increase their strength.