Proceratosaurus /proʊ̯sɛrətoʊˈsɔːrəs/ (from Greek πρό/πρότερος pro/protero 'before', κέρας/κέρατος keras/keratos 'horn' and σαῦρος sauros 'lizard') is a genus of carnivorous theropod dinosaur from the Middle Jurassic (Bathonian) of England.

[6] In 1910, the British paleontologist Arthur Smith Woodward reported a partial theropod skull discovered some time prior by F. Lewis Bradley during excavation for a reservoir at Minchinhampton, a town in the Cotswolds in Gloucestershire, England.

[2][3] Arthur Smith Woodward, who initially studied Proceratosaurus, placed it as a species of Megalosaurus, due to same number of premaxillary teeth (4).

Their study concluded that Proceratosaurus was in fact a coelurosaur, and moreover a tyrannosauroid, a member of the lineage leading to the giant tyrannosaurs of the Late Cretaceous.

They named the clade containing these two dinosaurs the Proceratosauridae, defined as all theropods closer to Proceratosaurus than to Tyrannosaurus, Allosaurus, Compsognathus, Coelurus, Ornithomimus, or Deinonychus.

[1][11] Below is a cladogram from a 2022 study by Darren Naish and Andrea Cau on the genus Eotyrannus:[12] Juratyrant Stokesosaurus Coeluridae Dilong Guanlong Proceratosaurus Sinotyrannus Yutyrannus Eotyrannus Xiongguanlong Megaraptora Dryptosaurus Appalachiosaurus Bistahieversor Teratophoneus Tyrannosauridae In 2024, the describers of Alpkarakush recovered Dilong and proceratosaurids (Proceratosaurus and Guanlong) outside Tyrannosauroidea based on their phylogenetic analysis.

[1] The flora from the roughly equivalently aged Taynton Limestone Formation in Oxfordshire is dominated by araucarian and cheirolepidiacean conifers as well as bennettitaleans and Pelourdea, representing a probably seasonally dry coastal environment.

[14] Other dinosaurs known from equivalently aged deposits from the Bathonian of Britain include the large theropod Megalosaurus,[15] the sauropod Cetiosaurus,[16] as well as indeterminate ornithischians[17] and maniraptorans.