Wednesday, November 30, 2016

Artist’s impression of how Victorian paleontologists thought Megalosaurus bucklandii looked (right), compared with how we now understand it to have looked (left). Image credit: Mark Garlick / University of Warwick.

Megalosaurus, (meaning “Great Lizard”), is a genus of large meat-eating theropod dinosaurs of the Middle Jurassic period (Bathonian stage, 166 million years ago) of Southern England. Although fossils from other areas have been assigned to the genus, the only certain remains of Megalosaurus come from Oxfordshire and date to the late Middle Jurassic.

Modern restoration of Megalosaurus, with mostly hypothetical head. Author: LadyofHats Mariana Ruiz Altered by FunkMonk and Steveoc 86

The type species is Megalosaurus bucklandii, named in 1827. In 1842, Megalosaurus was one of three genera on which Richard Owen based his Dinosauria. On Owen’s directions a model was made as one of the Crystal Palace Dinosaurs, which greatly increased the public interest for prehistoric reptiles. Subsequently, over fifty other species would be classified under the genus, originally because dinosaurs were not well known, but even during the 20th century after many dinosaurs had been discovered. Today it is understood these additional species were not directly related to M. bucklandii, which is the only true Megalosaurus species. Because a complete skeleton of it has never been found, much is still unclear about its build.
Megalosaurus skeleton, World Museum Liverpool, England. Found in southern England. Author: Rept0n1x
Megalosaurus’s evolutionary relationships are still something of a mystery to paleontologists. The few analyses that have been done place Megalosaurus outside the groups that include the allosaurids and the coelurosaurs and closer to an assemblage that includes the spinosaurids (including Spinosaurus and Baryonyx). However, even this possible close relationship with spinosaurids has not yet been definitively established.