Ceratosaurus was a theropod dinosaur in the Late Jurassic, around 150 million years ago. This genus was first described in 1884 by American paleontologist Othniel Charles Marsh based on a nearly complete skeleton discovered in Garden Park, Colorado, in rocks belonging to the Morrison Formation. In 2000 and 2006, a partial specimen from the Lourinhã Formation of Portugal was described, providing evidence for the presence of the genus outside of North America. Ceratosaurus was a predator with deep jaws supporting long, blade-like teeth. It had a prominent, ridge-like horn on the midline of the snout and a pair of horns over the eyes. The forelimbs were very short but remained fully functional, with four-fingered hands. The tail was thick from top to bottom. It shared its habitat with other large theropods including Torvosaurus and Allosaurus. It may have hunted plant-eating dinosaurs or aquatic prey such as fish. The nasal horn was probably used solely for display. (Full article...)