Open Paleo

Dakotaraptor

DePalma et al., 2015 duh-KO-tuh-RAP-tuh

Named after the Dakotas (the Hell Creek Formation of the western USA, spanning the Dakotas, Montana and Wyoming) + Latin raptor ('thief' or 'plunderer'), meaning 'thief from Dakota'.

72.2–66.0 million years ago Maastrichtian, Late Cretaceous
Late Cretaceous stages

Dakotaraptor is a possible chimeric genus of maniraptoriform theropod dinosaur that lived in western North America during the Late Cretaceous period. 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. One of the largest dromaeosaurids, measuring 4.35-6 m (14.3-19.7 ft) and weighing 220-350 kg (490-770 lb), 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 it is unclear whether further analysis of potential non-dromaeosaurid affinities of the holotype and referred material can be properly conducted, because currently the type specimen is housed in a private collection. Phylogenetic analyses of D. steini place it in a variety of positions within Dromaeosauridae.

Under dispute

The placement of Dakotaraptor is contested and complicated by a probable chimeric holotype (its "furcula" is a turtle entoplastron; Arbour and colleagues, 2015). It has been recovered as a dromaeosaurine (DePalma and colleagues, 2015; Currie and Evans, 2019), a velociraptorine (Pei and colleagues, 2020), and an unenlagiine (Hartman and colleagues, 2019). Given the spread of placements and the chimera concern, it is placed at Dromaeosauridae incertae sedis.

Diagnosis

  1. Lateral corial groove on pedal ungual IV fully enclosed in a bone tube for approximately half of its distal length
  2. Sharp ventral keel on pedal unguals II and III
  3. Fibular crest long and gracile, height does not exceed 9% of total length, with hooked proximal margin
  4. Shallow collateral ligament fossa on lateral side of metacarpal II, with proximodorsal margin straight in dorsal view
  5. Teeth with 15-20 denticles/5 mm on distal carina and 20-27 denticles/5 mm on mesial carina
  6. Row of 10 prominent ulnar papilli (quill knobs) on ventral ulnar ridge, first clear evidence for feather quills on a large dromaeosaurid forearm

Species

Dakotaraptor steini DePalma et al., 2015

Type species

Named for paleontologist Walter W. Stein.

Holotype
PBMNH.P.10.113.T , Palm Beach Museum of Natural History
Material
Partial skeleton of adult individual without skull, including vertebrae, humeri, ulnae, radii, metacarpals, claws, thighbone, shinbones, ankle and foot elements
Horizon
upper Hell Creek Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
Locality
Bone Butte, South Dakota, United States

References

  1. DePalma, R. A.; Burnham, D. A.; Martin, L. D.; Larson, P. L.; Bakker, R. T. (2015). The first giant raptor (Theropoda: Dromaeosauridae) from the Hell Creek Formation. The University of Kansas Paleontological Contributions 14: 1-16. University of Kansas. doi:10.17161/paleo.1808.18764 depalma2015a
  2. Ding, A.; Pittman, M.; Upchurch, P.; O'Connor, J.; Field, D. J.; Xu, X. (2020). The biogeography of coelurosaurian theropods and its impact on their evolutionary history. Pennaraptoran Theropod Dinosaurs: Past Progress and New Frontiers (Pittman, M.; Xu, X., eds.) 440: 117-157. American Museum of Natural History, New York.

    Names Bone Butte as the holotype's locality, which the description gives only to county level.

    ding2020a
  3. Arbour, V. M.; Zanno, L. E.; Larson, D. W.; Evans, D. C.; Sues, H. D. (2015). The furculae of the dromaeosaurid dinosaur Dakotaraptor steini are trionychid turtle entoplastra. PeerJ 3: e1691. PeerJ. doi:10.7717/peerj.1691

    Identified the holotype "furcula" as a trionychid turtle entoplastron, establishing the chimeric nature of the referred material.

    arbour2015b
  4. Currie, P. J.; Evans, D. C. (2019). Cranial Anatomy of New Specimens of Saurornitholestes langstoni (Dinosauria, Theropoda, Dromaeosauridae) from the Dinosaur Park Formation (Campanian) of Alberta. The Anatomical Record 303(4): 691-715. Wiley. doi:10.1002/ar.24241

    Recovered Dakotaraptor within Dromaeosaurinae in its phylogenetic analysis.

    currie2019a
  5. Hartman, S.; Mortimer, M.; Wahl, W. R.; Lomax, D. R.; Lippincott, J.; Lovelace, D. M. (2019). A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ 7: e7247. PeerJ. doi:10.7717/peerj.7247

    Recovered Dakotaraptor as an unenlagiine in its large paravian analysis.

    hartman2019a
  6. Pei, R.; Pittman, M.; Goloboff, P. A.; Dececchi, T. A.; Habib, M. B.; Kaye, T. G.; Larsson, H. C. E.; Norell, M. A.; Brusatte, S. L.; Xu, X. (2020). Potential for Powered Flight Neared by Most Close Avialan Relatives, but Few Crossed Its Thresholds. Current Biology 30(20): 4033-4046.e8. Elsevier BV. doi:10.1016/j.cub.2020.06.105

    Recovered Dakotaraptor as a velociraptorine.

    pei2020a
  7. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026c