When it was discovered in 1952, the nature of the Mamenchisaurus constructus vertebrae was unclear. The vertebrae were so delicate and poorly preserved that they could not be excavated undamaged. Early restorations of this animal showed only a moderate length of neck. It was with the discovery of M. hochuanensis in 1957 that the fantastic length of the neck was appreciated.
Name: Mamenchisaurus, meaning ‘lizard from Mamen Brook’
Size: 21-22m long and 5m high
Lived: 145 million years ago in China during the Late Jurassic Period
Mamenchisaurus has the longest neck of any known dinosaur. It consists of 19 vertebrae – the greatest number so far found – and is about 14m long, taking up about two-thirds of the length of the entire animal. The vertebrae are very thin and lightweight, made up of fine struts and sheets, rather like the later diplodocids. However, the short, deep skull shows that it belongs to the more primitive euhelopid group.
Mamenchisaurus’ long neck was supported by long, overlapping bones, which must have made the neck quite stiff and slow to turn. The neck also had strong muscles which supported its small, snake-like head. Mamenchisaurus was as long as a tennis court, but its body was slim. Its backbone was hollowed out in places, which made it very light for its size. The extreme length of its neck may have enabled Mamenchisaurus to reach in between closely-spaced trees to eat undergrowth in dense woodland.
145 million years ago, the area where this dinosaur lived was covered with vast, dense forests of redwood and sequoia trees. Herds of Mamenchisaurus lumbered along, using their small, peg-like teeth to nip off leaves and small shoots on the treetops that were out of the reach of other dinosaurs.
Mamenchisaurus walked on four legs, dragging its long, thin tail along the ground behind it. During the mating season, male Mamenchisaurus may have used their tails to lash each other in various fights for the females of the herd.