Cryolophosaurus ( or ; "CRY-oh-loaf-oh-SAWR-us") is a genus of large theropod dinosaur known from only a single species Cryolophosaurus ellioti, from the early Jurassic of Antarctica. It was one of the largest theropods of the Early Jurassic, with the subadult being estimated to have reached long and weighed . Cryolophosaurus was first excavated from Antarctica's Early Jurassic, Pliensbachian aged Hanson Formation, formerly the upper Falla Formation, by paleontologist Dr. William Hammer in 1991. It was the first carnivorous dinosaur to be discovered in Antarctica and the first non-avian dinosaur from the continent to be officially named. The sediments in which its fossils were found have been dated at ~194 to 188 million years ago, representing the Early Jurassic Period. Cryolophosaurus is known from a skull, a femur and other material, all of which have caused its classification to vary greatly. The femur possesses many primitive characteristics that have classified Cryolophosaurus as a dilophosaurid or a neotheropod outside of Dilophosauridae and Averostra, whereas the skull has many advanced features, leading the genus to be considered a tetanuran, an abelisaurid, a ceratosaur and even an allosaurid. Cryolophosaurus is currently considered to be a derived neotheropod, close to Averostra. Additionally, Cryolophosaurus possessed a distinctive "pompadour" crest that spanned the head from side to side. Based on evidence from related species and studies of bone texture, it is thought that this bizarre crest was used for intra-species recognition. The brain of Cryolophosaurus was also more primitive than those of other theropods. Discovery and naming Cryolophosaurus originally was collected during the 1990–91 austral summer on Mount Kirkpatrick in the Beardmore Glacier region of the Transantarctic Mountains. The discovery was made by Hammer, a professor at Augustana College, and his team. The fossils were found in the siliceous siltstone of the Hanson Formation, formerly the upper Falla Formation, and dated to the Pliensbachian Stage of the early Jurassic. Cryolophosaurus was the second dinosaur, and first theropod, to be discovered in Antarctica. It was discovered after Antarctopelta, but named earlier. In 1991, both Hammer and the Ohio State University geologist David Elliot excavated separate outcrops near Beardmore Glacier, sharing logistical expenses. Elliot's team first came across the remains of Cryolophosaurus in a rock formation around the altitude of high and about from the South Pole. When the discovery was made, they soon notified Hammer. Over the next three weeks, Hammer excavated of fossil-bearing rock. The team recovered