Brontosaurus
"Brontosaurus" was a large, long-necked quadrupedal animal with a long, whip-like tail, and forelimbs that were slightly shorter than its hindlimbs. The largest species, "B. excelsus", weighed up to and measured up to long from head to tail. For comparison, the current largest land animal, the average male African bush elephant is 3.20 m (10.5 ft) tall at the shoulder and has a body mass of 6,000 kg (13,228 lb) or 6.6 short tons.
Ankylopollexia
Ankylopollexians varied greatly in size over the course of their evolution. An early genus, "Camptosaurus" is thought to have reached a maximum size of in length. Gregory S. Paul contends that "Camptosaurus" was smaller, no more than in length and half a tonne in weight. The largest known ankylopollexian, dating to the late Campanian age (around 70 million years ago), belonged to the hadrosaurid family, and is named "Shantungosaurus". It was around to in length and weighed, for the largest individuals, up to . An Early Cretaceous genus from England, "Mantellisaurus", weighed about .