Dinosauria

Sanxiasaurus modaoxiensis, a neornithischian dinosaur.

Nevadadromeus schmitti, a neornithischian dinosaur.

Forearm and hand of Machairasaurus leptorhynchos Longrich et al. 2010 (Dinosauria: Theropoda: Oviraptoridae: Ingeniinae) from the Late Cretaceous Djadokhta Formation beds of Bayan Mandahu, Inner Mongolia, China. Digital photography and editing by Nick Longrich

Portraits of the theropod dinosaur Alpkarakush

Oviraptorian dinosaur

Fossil of Lurdusaurus, an ornithopod dinosaur Took the photo at Musee d'Histoire Naturelle, Brussels

Comptonatus is an iguanodontid ornithopod dinosaur that lived about 125 million years ago, in the Early Cretaceous of what is now Europe. It was a medium sized herbivore at about 7 m in length, and weighed around 1 t in body mass. Fossilized footprints found near the original specimen indicate that Comptonatus was likely a herding animal. Comparisons between Comptonatus and other iguanodontids that lived around the same time and region show a high rate of diversity. This indicates there may have been pressure for speedy evolutionary adaptation in the region, or perhaps a high volume of migration.

Changmiania liaoningensis, an ornithopod dinosaur from the Lower Cretaceous of Lujiatun (Liaoning Province, China). (A) Holotype PMOL AD00114 in dorsal view; (B) anterior part of the holotype PMOL AD00114 in caudolateral view; (C) referred specimen PMOL LFV022 in dorsal view. Red arrows indicate the emplacement of the gastrolith clusters.

Dinosaur National Monument is a United States National Monument located on the southeast flank of the Uinta Mountains on the border between Colorado and Utah at the confluence of the Green and Yampa Rivers. Although most of the monument area is in Moffat County, Colorado, the Dinosaur Quarry is located in Utah just to the north of the town of Jensen, Utah. The nearest communities are Jensen, Utah, and Dinosaur, Colorado. The park contains over 800 paleontological sites and has fossils of dinosaurs including Allosaurus, Deinonychus, Abydosaurus (a nearly complete skull, lower jaws and first four neck vertebrae of the specimen DINO 16488 found here at the base of the Mussentuchit Member of the Cedar Mountain Formation is the holotype for the description) and various long-neck, long-tail sauropods. It was declared a National Monument on October 4, 1915. The rock layer enclosing the fossils is a sandstone and conglomerate bed of alluvial or river bed origin known as the Morrison Formation from the Jurassic Period some 150 million years old. The dinosaurs and other ancient animals were carried by the river system which eventually entombed their remains in Utah. The pile of sediments were later buried and lithified into solid rock. The layers of rock were later uplifted and tilted to their present angle by the mountain building forces that formed the Uintas during the Laramide orogeny. The relentless forces of erosion exposed the layers at the surface to be found by paleontologists. The dinosaur fossil beds (bone beds) were discovered in 1909 by Earl Douglass, a paleontologist working and collecting for the Carnegie Museum of Natural History. He and his crews excavated thousands of fossils and shipped them back to the museum in Pittsburgh, Pennsylvania for study and display. President Woodrow Wilson proclaimed the dinosaur beds as Dinosaur National Monument in 1915. The monument boundaries were expanded in 1938 from the original 80-acre (320,000 m2) tract surrounding the dinosaur quarry in Utah, to its present extent of over 200,000 acres (800 km²) in Utah and Colorado, encompassing the spectacular river canyons of the Green and Yampa. Though lesser-known than the fossil beds, the petroglyphs in Dinosaur National Monument are another treasure the monument holds. Due to problems with vandals, many of the sites are not listed on area maps. The "Wall of Bones" located within the Dinosaur Quarry building in the park consists of a steeply tilted (67° from horizontal) rock layer which contains hundreds of dinosaur fossils. The enclosing rock has been chipped away to reveal the fossil bones intact for public viewing. In July 2006, the Quarry Visitor Center was closed due to structural problems that since 1957 had plagued the building because it was built on unstable clay. The decision was made to build a new facility elsewhere in the monument to house the visitor center and administrative functions, making it easier to resolve the structural problems of the quarry building while still retaining a portion of the historic Mission 66 era exhibit hall. It was announced in April 2009 that Dinosaur National Monument would receive $13.1 million to refurbish and reopen the gallery as part of the Obama administration's $750 billion stimulus plan. The Park Service successfully rebuilt the Quarry Exhibit Hall, supporting its weight on 70-foot steel micropile columns that extend to the bedrock below the unstable clay. The Dinosaur Quarry was reopened in Fall 2011. en.wikipedia.org/wiki/Dinosaur_National_Monument en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_...

fossil Europasaurus, Aathal Dinosaur Museum.

Dentary of the hadrosauroid dinosaur Fylax thyrakolasus gen. et sp. nov. (IPS-36338, holotype) from the uppermost Maastrichtian Fontllonga-R locality; in posterior (A1), medial (A2), dorsal (A4), anterior (A5), lateral (A6), and ventral (A7) views. A detailed lingual view of the tooth crowns appears in A3.

Right hind limb of the sauropodomorph dinosaur Musankwa sanyatiensis gen. et sp. nov. (NHMZ 2521) from the Pebbly Arkose Formation (Norian, Upper Triassic) of Spurwing Island, Zimbabwe. A. Right femur in posterior (A1), lateral (A2), anterior (A3), medial (A4), proximal (A5), and distal (A6) views. B. Right tibia with conjoined astragalus in anterior (B1), lateral (B2), posterior (B3), medial (B4), and proximal (B5) views.

Reconstruction of Tuebingosaurus maierfritzorum gen. et sp. nov. as a quadruped dinosaur, using the outline of Riojasaurus as a base ‒ next to the silhouette of Friedrich von Huene. The drawing of the bones is based on and modified from the original illustrations of specimen “GPIT IV” in von Huene (1932, pl. 38) that have been replicated in the literature. The right fibula is marked in grey as it was found nearby with similar measurements to the left fibula and has been assumed to be part of the same individual.

Reconstruction of Bravasaurus arreirosorum a titanosaur dinosaur from the Late Cretaceous of Argentina

Shri rapax 3D skeletal reconstruction by Alex Pritchard of Dinosaur Skeletons.

Reconstructed skull of Jaxartosaurus aralensis Riabinin, 1937. Only a posterior portion of the skull, as well as a surangular is known, with the rest of the skull being based mostly upon File:Aralosaurus skull.png. Jaxartosaurus is currently classified as a basal lambeosaurine, more derived than Aralosaurini, but more primitive than Parasaurolophini and Lambeosaurini. It might be more derived than Tsintaosaurini (Godefroit et al., 2004). References: Riabinin, A.M. (1937). "A New Finding of Dinosaurs in the Trans-Baikal Region". Ezhegodn. Vserossijskogo Palaeont. Obstcg. 11: 142–144 Godefroit, P.; Bolotsky, Y.L.; Van Itterbeeck, J. (2004). "The lambeosaurine dinosaur Amurosaurus riabinini, from the Maastrichtian of Far Eastern Russia". Acta Palaeontologica Polonica 49(4): 585–618