Megalosaurus was a substantial animal around nine metres long, with a large head filled with long, sharp, serrated teeth. In appearance it resembled the much later T. rex, but Megalosaurus was around three-quarters the size, with larger and more functional forelimbs, although it walked on two feet.
This specimen is the right, lower jaw of the dinosaur. It was found by workers in a former roof tile mine in the early 18th century, near the aptly-named village of Stonesfield, north-west Oxfordshire. Geologically, it is from the Middle Jurassic Great Oolite Group of rocks, and is approximately 167 million years old.
The jaw was part of a group of large, unusual bones studied by Dean William Buckland - the innovative and practically-minded Professor of Geology at the University of Oxford in the early 19th century. With the help of French anatomist Georges Cuvier, Buckland realised this was an ancient reptile unlike any alive today. He gave it the new genus name Megalosaurus (meaning ‘great lizard’) in 1824, almost 20 years before the term ‘dinosaur’ was coined by Richard Owen.
Megalosaurus was the top predator in the area of the Jurassic supercontinent Laurasia that later became the British Isles. It is a relatively early and comparatively unspecialised theropod, or ‘beast-footed’ dinosaur, but is a representative of a group of predatory dinosaurs which later gave rise to Cretaceous period giants such as Spinosaurus.
This specimen constitutes part of the holotype of the dinosaur species Megalosaurus bucklandi von Meyer, 1832. A holotype is the voucher specimen with which all other specimens of the named species are compared. This makes the Museum’s Megalosaurus jaw a reference point of global importance for scientists working on this group of dinosaurs.