Megalosaurus is a megalosaurid theropod dinosaur from the Middle Jurassic of the United Kingdom. It was officially named in 1824 by William Buckland. It was the first non-avian dinosaur known to science, and when it was discovered, a part of its upper leg bone was confused for being the testes of a giant (hence its early name, Scrotum humanum); as well as this, it was a wastebasket taxon, as many theropods, such as Dilophosaurus, Eustreptospondylus, Carcharodontosaurus, and Majungasaurus were once considered to be species directly related to this genus, right before being classified as their own genera.
Physiology
Megalosaurus resembled a large, bipedal lizard. It had a semi-bulky body, a long tail, moderately-sized arms with 3 fingers on each hand, and a large head with a mouth containing lots of big teeth. Its body would have been covered in scaly skin.
Diet
Megalosaurus was a predator, preying on mid-sized sauropods, small pterosaurs, and smaller theropods. Its teeth had knife-like serrations from front to back, and were used to cut into the hides of large prey.
Ecology
The way how Megalosaurus should be constructed was under debate for a long time, with people reconstructing it as a dragon, a bipedal, tail dragging, kangaroo-like reptile, and a bipedal, digitigrade saurischian; today, the latter prevails as the most accepted reconstruction. As well as this, it was the largest European theropod during the Middle Jurassic, and so, it would be presumed that would be an apex predator; however, Western Europe was starting to break up into islands at the time, and due to the fact that Megalosaurus fossils were found in marine habitats, we can assume that the theropod went near the shore sometimes. Of course, one explanation is that it was just like any other theropod, and would only come onto the beach whenever it moved from place to place; other explanations are that it ran near the shore to eat any aquatic testudines resting there, and that it was a full-blown beach comber, scavenging washed-up marine reptile carcasses and snagging fish trapped in tidal pools with its jaws. Either way, with the shrinking landmasses of Europe during the time, Megalosaurus would have had to exploit any available food resources for its own well-being.
In popular culture
Megalosaurus was one of the 1st Mesozoic animals discovered, so it was featured in Crystal Palace Park (a pleasure ground in London) as a large, quadrupedal dragon, alongside Iguanodon (depicted as an herbivorous dragon), Pterodactylus, Mosasaurus (depicted as a large, iguana-like squamate), Plesiosaurus, and Ichthyosaurus. Since then, it has been featured in major pieces of media such as the Lost World novel and the 1991 sitcom Dinosaurs; however, after getting overshadowed by the later-discovered Allosaurus and Tyrannosaurus, the megalosaur received a drop in popularity, only appearing in certain dinosaur games.