Temporal range: Middle Jurassic
|Fossil specimens referred to M. bucklandii, Oxford University Museum of Natural History.|
Megalosaurus was a large meat-eating theropod dinosaur of the Middle Jurassic of Europe. It was found in 1824, and was the earliest dinosaur named. In 1827, Gideon Mantell included Megalosaurus in his geological survey of southeastern England. He gave the species its name, Megalosaurus bucklandii.
Because a complete skeleton of it has never been found, much is still unclear about its build. The first naturalists who investigated Megalosaurus thought it was a gigantic lizard of twenty metres length. In 1842 Richard Owen concluded that it was no longer than nine metres, standing on upright legs as a quadruped.
Later it was realised that all theropods were bipedal. Today is known that the early proto-dinosaurs in the late Middle Triassic were also bipedal. Certainly Eoraptor, from 231.4 million years ago, was bipedal. That means the dinosaurs were bipedal from the start (primatively bipedal). Only the heavier sauropods and armoured dinosaurs became quadrupedal, standing on all four legs.
References[change | change source]
- Mantell G. 1827. Illustrations of the geology of Sussex: a general view of the geological relations of the southeastern part of England, with figures and descriptions of the fossils of Tilgate Forest.
- Sereno P.C. et al 1993 Primitive dinosaur skeleton from Argentina and the early evolution of Dinosauria. Nature 361: 64–66. doi:10.1038/361064a0.
- Sereno PC (1999). "The evolution of dinosaurs". Science 284 (5423): 2137–2147. doi:10.1126/science.284.5423.2137. PMID 10381873.