Megalosaurus

Megalosaurus (meaning "great lizard", from Greek μέγας, megas, meaning 'big', 'tall' or 'great' and σαῦρος, sauros, meaning 'lizard') is an extinct genus of large meat-eating theropod dinosaurs that lived during the Middle Jurassic Epoch (Bathonian stage, about 166 million years ago) in southern England.

The earliest pieces of Megalosaurus were found in the 1600s, but it was given its name in 1824 by William Buckland. This made Megalosaurus the very first dinosaur to have a name. It helped scientists learn that dinosaurs were a special group of ancient reptiles.

Megalosaurus was about 6 metres (20 ft) long and weighed around 700 kilograms (1,500 lb). It walked on two strong back legs, with a balancing tail and shorter front legs. This dinosaur had a large head with long, curved teeth, and it was a powerful hunter. At the time it lived, Europe was made of many islands, and Megalosaurus was likely the biggest hunter on its island. It lived near other dinosaurs, such as the large plant-eater Cetiosaurus.

Discovery and naming↓ naming

In 1699, Edward Lhuyd described what he thought was a fish tooth. This tooth was later found to be from an unknown species of Megalosaurus. It was collected near Witney, Oxfordshire.

The earliest possible fossil of Megalosaurus was a piece of a femur found in Oxfordshire in 1676. It was first thought to be from a Roman war elephant or even a giant human. This bone was shown in a book in 1676 by Robert Plot. In 1815, John Kidd reported finding giant bones at a quarry in Stonesfield. These bones were studied by William Buckland, who identified them as belonging to a large lizard-like creature. In 1822, the name “Megalosaurus” was proposed, meaning “great lizard.” It was formally named by Buckland in 1824, making Megalosaurus the first non-avian dinosaur genus to be named.

Description

Since the first discovery of Megalosaurus, many more bones have been found, but no complete skeleton has ever been uncovered. Because of this, scientists are not completely sure about its exact appearance.

Traditionally, Megalosaurus was thought to be about 30 feet (9 meters) long. But estimates have varied over time. Some scientists have suggested it was as short as 20 feet (6 meters). In general, Megalosaurus looked like a large meat-eating dinosaur. It walked on two legs, with a long tail for balance. Its hind legs were long and strong, while its front legs were shorter but very sturdy. It had sharp teeth for catching and eating its prey.

Phylogeny

In 1824, a scientist named Buckland put Megalosaurus in a group called Sauria. He thought it was like modern lizards. In 1842, another scientist named Owen named Megalosaurus as one of the first three dinosaurs ever found. By 2012, scientists used a method called cladistics to learn that Megalosaurus was closely related to another dinosaur called Torvosaurus. This helped scientists learn more about where Megalosaurus fits among other dinosaurs.

Main article: Megalosauridae
Main articles: Cladistics, List of dinosaurs

Paleobiology

Megalosaurus lived in what is now Europe during the Bathonian stage of the Middle Jurassic, about 166-168 million years ago. It was one of the big predators in its habitat. It likely hunted other dinosaurs such as stegosaurs and sauropods. Scientists think Megalosaurus lived on an island made up of parts of southern Britain and nearby areas of northern France, the Netherlands, Belgium, and western Germany. This island was connected to a larger landmass.

One rib of Megalosaurus shows a healed fracture, suggesting these dinosaurs could survive injuries. The area where Megalosaurus lived had many kinds of plants, including conifers, ferns, and other ancient plants. This created a coastal environment that might have been dry at times and included mangroves.

Species and synonyms

In the 1800s, Megalosaurus was thought to be the typical meat-eating dinosaur. If dinosaur fossils were not clear enough to be their own group, they were often called Megalosaurus. This meant Megalosaurus had more species than any other dinosaur group, but many of these were not well described.

In 1857, Joseph Leidy changed the name of Deinodon horridus to Megalosaurus horridus. In 1858, Friedrich August Quenstedt named Megalosaurus cloacinus from a single tooth. Many scientists named new Megalosaurus species during the 1800s and early 1900s, often using just one tooth or a small piece of bone. Today, these species are often considered unsure or placed in different groups.

Some well-known examples include:

• Megalosaurus ingens, a large tooth from German East Africa, is now thought to belong to Torvosaurus.
• Megalosaurus poikilopleuron was renamed from Poekilopleuron bucklandii and is usually accepted today.
• Megalosaurus wetherilli, based on a fairly complete skeleton from Arizona, was later given its own group, Dilophosaurus.

Over time, many of these species were looked at again and either renamed or moved to different groups.