Dakotaraptor (meaning “thief from Dakota”) is a possible chimaeric[a][2] genus of maniraptoriform theropod dinosaur that lived in western North America during the Late Cretaceous period.

[3] The remains have been found in the Maastrichtian-aged Hell Creek Formation, dated to the very end of the Mesozoic era, making Dakotaraptor potentially one of the last surviving dromaeosaurids, though other researchers have disputed its classification.

[7][8] The holotype, PBMNH.P.10.113.T, was found in a sandstone layer of the upper Hell Creek Formation, dating to the late Maastrichtian.

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 (originally identified as a furcula, but now also excluded from the known remains of Dakotaraptor).

Other referred fossils are KUVP 156045 (an isolated tooth)[1] and NCSM 13170 (a third supposed furcula that was later identified as not belonging to Dakotaraptor).

[9] The elements originally identified as the furcula of Dakotaraptor were U- to V-shaped, suggested by the describers to be similar to many other dromaeosaurids, such as Velociraptor, and even the large spinosaurid theropod Suchomimus.

In 2015, a study by Victoria Megan Arbour et al. proposed that the presumed Dakotaraptor furculae in fact represented a part of a turtle’s armor, the entoplastron of Axestemys splendida, a member of Trionychidae.

[9] In 2024, even the dinosaurian elements of Dakotaraptor were questioned, with supposed traits diagnostic for dromaeosaurs also referrable to caenagnathids and ornithomimosaurians.

The "blood groove" on the outer side of the fourth claw of the foot, towards the tip, is fully enclosed over half of its length, forming a bony tubular structure.

When the arm is seen in a flat position, of the second metacarpal, the edge between the wrist joint and the upper shaft is straight in top view.

The most notable anatomical feature is the row of very prominent bumps along a ridge on the lower edge of the ulna, one of the forearm bones.

Dakotaraptor’s quill knobs show that the animal unequivocally had prominent wing feathers, making it the largest dromaeosaurid with confirmed plumage of that type.

The wingspan of Dakotaraptor was estimated at 120 centimetres (47 in), not taking into account possible primary remiges longer than the hand.

[1] The second metacarpal of the metacarpus of the hand, the bone that primary remiges attach to, also had a flat bony shelf as its dorsal surface.

Dakotaraptor more closely resembles the agile, springy smaller dromaeosaurids and would have been well-suited to running and pursuit predation.

Dakotaraptor has a flexor tubercle that is larger relative to overall claw size than it is in other discovered dromaeosaurids, potentially giving it the strongest slashing strength of any known member of this group.

[3] Acheroraptor temertyorum is another theropod from the Hell Creek Formation, named in 2013 for a lower jaw, a maxilla, and some teeth.

[1] On the ulna of the lower arm, wide quill knobs are present, attachment points for large pennaceous feathers (as previously mentioned).

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 that had them.

[1] Dakotaraptor is the first medium-sized predator discovered in the Hell Creek Formation (aside from the dubious Nanotyrannus), intermediate in length between the giant tyrannosaurid Tyrannosaurus and smaller Deinonychosaurians, like Acheroraptor.

[15] As its tibia was longer than its femur, Dakotaraptor would have had a high running capacity, filling the niche of a pursuit predator.

It lived alongside other famous Hell Creek dinosaurs, including the aforementioned Tyrannosaurus, Triceratops, Pachycephalosaurus, Ornithomimus, and Edmontosaurus.