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.
Evolution of dinosaurs
Heterodontosauridae has been shown to be the basalmost group within Ornithischia. Heterodontosaurids are very small (body length < 1 m) and lived from the Late Triassic to Early Cretaceous. Apart from "Abrictosaurus" all have a short upper canine and longer lower canine. The forelimbs in known fossils are relatively long.