|
''Dakotaraptor steini'' is a species of large carnivorous theropod dromaeosaurid dinosaur from the Late Cretaceous of North America. The first fossils of ''Dakotaraptor'' were found in South Dakota, USA, in 2005. In 2015, the genus ''Dakotaraptor'' received its name, meaning "plunderer of Dakota", when the type species ''Dakotaraptor steini'' was described. The fossils contain an incomplete skeleton without a skull and some individual bones. They have been found in the Maastrichtian-age Hell Creek Formation, dated to the very end of the Cretaceous period, making ''Dakotaraptor'' one of the last surviving dromaeosaurids. ''Dakotaraptor'' was about five to six metres long, which makes it one of the largest dromaeosaurids known. It had long arms. One of the lower arm bones shows bumps for feathers, proving that ''Dakotaraptor'' had wings. It also had long rear legs with a very large sickle claw on the second toe. The claw could be used to kill relatively large plant-eating dinosaurs. ''Dakotaraptor'' lived in the same time and area as ''Tyrannosaurus rex''. ==Discovery== In 2005, paleontologist Robert DePalma in Harding County, South Dakota discovered the skeleton of a large dromaeosaurid. Subsequently, the same site produced additional dromaeosaurid remains, as well as abundant other fossils in 2010 described by DePalma in his master's thesis. In 2015, the type species ''Dakotaraptor steini'' was named and described by Robert A. DePalma, David A. Burnham, Larry Dean Martin, Peter Lars Larson and Robert Thomas Bakker. The generic name combines a reference to South Dakota and the Dakota people with a Latin ''raptor'', "plunderer". The specific name honours paleontologist Walter W. Stein. The holotype, PBMNH.P.10.113.T, was found in a sandstone layer of the upper Hell Creek Formation, dating from the late Maastrichtian. It consists of a partial skeleton, lacking the skull, of an adult individual. It contains a piece of a back vertebra, ten tail vertebrae, a furcula, both upper arm bones, both ulnae, both radii, the first and second right metacarpals, three claws of the left hand, a right thighbone, both shinbones, a left astragalus bone, a left calcaneum, the left second, third and fourth metatarsal, the right fourth metatarsal, and the second and third claw of the right foot. Apart from the remains of the holotype, in the site bones were discovered that also belonged to ''Dakotaraptor'' but which represented a more gracile morph. These included the specimens PBMNH.P.10.115.T: a right shinbone; PBMNH.P.10.118.T: a connected left astragalus and calcaneum; and KUVP 152429: a furcula. Additionally four isolated teeth were referred, specimens PBMNH.P.10.119.T, PBMNH.P.10.121.T, PBMNH.P.10.122.T, and PBMNH.P.10.124.T. These fossils are part of the collection of The Palm Beach Museum of Natural History. Other referred fossils are NCSM 13170, a furcula, and KUVP 156045, an isolated tooth.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dakotaraptor」の詳細全文を読む スポンサード リンク
|