Proceratosaurus

Proceratosaurus (/proʊsɛrətoʊˈsɔːrəs/ proh-seh-rə-toh-SAWR-əs) is a genus of theropod dinosaur that lived during the Middle Jurassic in what is now England. The holotype and only known specimen consists of a mostly complete skull with an accompanying lower jaw and a hyoid bone, found near Minchinhampton, a town in Gloucestershire. It was originally described as a species of Megalosaurus in 1910, M. bradleyi, but was moved to its own genus, Proceratosaurus, in 1926. The genus was named for its supposed close relationship with Ceratosaurus, later shown to be erroneous, due to perceived resemblance of Proceratosaurus' incomplete cranial crest to Ceratosaurus' nasal horn.

A small to medium-sized dinosaur, the skull of Proceratosaurus is 26.9 cm (10.6 in) long as preserved, and the dinosaur is estimated to have measured around 3 metres (10 ft) in length. The skull is characterised by a number of distinguishing features, including a cranial crest that begins at the junction between the premaxilla and the nasal bone. The teeth are heterodont, having D-shaped teeth at the front of the upper jaw and flattened serrated teeth in the sides of the jaw. Proceratosaurus is considered a coelurosaur, specifically a member of the family Proceratosauridae, and is among the earliest known members of both Coelurosauria and Tyrannosauroidea (the broader group which includes the tyrannosaurids, including the famous Tyrannosaurus), with its complete crest probably being larger than that of Ceratosaurus and more similar to its close relative Guanlong.

Proceratosaurus is thought to have been a carnivore, with its diet probably consisting of relatively small prey. The crest was probably used for display. The dinosaur is known from the Great Oolite Group of England, having been found in either the White Limestone Formation or the Forest Marble Formation. During the Bathonian age when Proceratosaurus lived, Britain along with the rest of Western Europe formed a subtropical island archipelago, with southern Britain having a seasonally dry climate. Other dinosaurs known from the Bathonian of Britain include the large theropod Megalosaurus bucklandii, the large sauropod Cetiosaurus, as well as indeterminate stegosaurs, ankylosaurs and heterodontosaurids.