page_title: Marshosaurus
section_title: Discovery and naming
hierarchical_section_title: Marshosaurus / Discovery and naming
caption_attribution_description: Marshosaurus sp. (or Marshosaurus bicentesimus) theropod dinosaur skull (reconstructed) from the Jurassic of Utah, USA (public display, CM 21704, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA). Stratigraphy: Morrison Formation, Upper Jurassic Localty: Dinosaur National Monument, northeastern Utah, USA Theropod were small to large, bipedal dinosaurs. Almost all known members of the group were carnivorous (predators and/or scavengers). They represent the ancestral group to the birds, and some theropods are known to have had feathers. Some of the most well known dinosaurs to the general public are theropods, such as Tyrannosaurus, Allosaurus, and Spinosaurus.
context_page_description: Marshosaurus is a genus of medium-sized carnivorous theropod dinosaur, belonging to the Megalosauroidea, from the Late Jurassic Morrison Formation of Utah and possibly Colorado.
context_section_description: During the 1960s, over fourteen thousand fossil bones were uncovered at the Cleveland-Lloyd Quarry in central Utah. The majority of these belonged to Allosaurus but some were of at least two theropods new to science. In 1974 one of these was named by James Henry Madsen Jr. as the genus Stokesosaurus.
  In 1976 the second was by Madsen named as the type species Marshosaurus bicentesimus. The generic name honoured the nineteenth century paleontologist Professor Othniel Charles Marsh, who described many dinosaur fossils during the Bone Wars. The specific name was chosen "in honor of the bicentennial of the United States of America".
  The holotype, UMNH VP 6373, was found in a layer of the Brushy Basin Member of the Morrison Formation dating from the late Kimmeridgian, approximately 155 - 152 mya. It is a left ilium, or upper pelvis bone. The paratypes consisted of three bones: the ischia UMNH VP 6379 and UMNH VP 380 and the pubic bone UMNH VP 6387. Three ilia and six jaw fragments were provisionally referred. The material represents at least three individuals.
  In 1991, Brooks Britt referred tail vertebrae from Colorado, because they resembled non-identified tail vertebrae fragments from the Cleveland-Lloyd Dinosaur Quarry. In 1993 a partial skeleton, CMNH 21704, from the Dinosaur National Monument was referred because its dorsal neural spines resembled non-identified spines from the Cleveland-Lloyd Dinosaur Quarry. This specimen was also the subject of a 1997 SVP abstract.
caption: Reconstructed skull of Marshosaurus at the Carnegie Museum of Natural History, based on referred material
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