page_title: Dakotaraptor
section_title: Paleobiology
hierarchical_section_title: Dakotaraptor / Paleobiology
caption_attribution_description: English: Life reconstruction of Dakotaraptor for DePalma et al 2015, showing the animal engaged in "RPR behavior" with Ornithomimus prey.
context_page_description: Dakotaraptor is a potentially chimaeric genus of large dromaeosaurid theropod dinosaur that lived in North America during the Late Cretaceous period. The remains have been found in the Maastrichtian stage of the Hell Creek Formation, dated to the very end of the Mesozoic era, making Dakotaraptor one of the last surviving dromaeosaurids. The remains of D. steini were discovered in a multi-species bonebed. Elements of the holotype and referred specimens were later found to belong to trionychid turtles, and further analysis of potential non-dromaeosaurid affinities of the holotype and referred material have not yet been conducted. Phylogenetic analyses of D. steini place it in a variety of positions in the Dromaeosauridae.
context_section_description: The keeled claw of the second toe, the "sickle claw", was used to bring down prey and had a more robust flexor tubercle than that of Utahraptor. To the contrary, the third foot claw was relatively smaller in size than with other dromaeosaurids and seems not to have had an important function in attacking prey animals.
  Two morphs, a robust and a gracile one, were present in the fossil material. A study of the bone histology showed that both morphs were adult, so the lighter build of some bones was not caused by a young age. Individual variety or pathologies might account for the difference but the simplest explanation is sexual dimorphism. It can as yet not be deduced which morph was male and which female.
  On the ulna of the lower arm, wide papillae ulnares or quill knobs are present, attachment points for large pennaceous feathers. Adult Dakotaraptor individuals were much too heavy to fly. Despite this flightless condition, the feathers were not reduced. There is a variety of possible alternative functions for its wings, including shielding of eggs, display, intimidation and keeping balance while pinning down prey with the sickle claw. These functions however, do not necessitate quill knobs and the describing authors considered it likely that Dakotaraptor descended from a smaller flying ancestor which had them.
caption: Dakotaraptor might have used its arms to keep its balance while subduing prey; here Ornithomimus is the victim
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