THE FIRST GIANT RAPTOR (THEROPODA: DROMAEOSAURIDAE)
FROM THE HELL CREEK FORMATION
Most dromaeosaurids were small- to medium-sized cursorial, scansorial, and arboreal, sometimes volant predators, but a
comparatively small percentage grew to gigantic proportions. Only two such giant “raptors” have been described from North
America. Here, we describe a new giant dromaeosaurid, Dakotaraptor steini gen. et sp. nov., from the Hell Creek Formation
of South Dakota. The discovery represents the first giant dromaeosaur from the Hell Creek Formation, and the most recent
in the fossil record worldwide. A row of prominent ulnar papilli or “quill knobs” on the ulna is our first clear evidence for
feather quills on a large dromaeosaurid forearm and impacts evolutionary reconstructions and functional morphology of such
derived, typically flight-related features. The presence of this new predator expands our record of theropod diversity in latest
Cretaceous Laramidia, and radically changes paleoecological reconstructions of the Hell Creek Formation.
Keywords: Maastrichtian, maniraptoran, Laramidia, flightless, ulnar papillae, paleoecology
FROM THE HELL CREEK FORMATION
Most dromaeosaurids were small- to medium-sized cursorial, scansorial, and arboreal, sometimes volant predators, but a
comparatively small percentage grew to gigantic proportions. Only two such giant “raptors” have been described from North
America. Here, we describe a new giant dromaeosaurid, Dakotaraptor steini gen. et sp. nov., from the Hell Creek Formation
of South Dakota. The discovery represents the first giant dromaeosaur from the Hell Creek Formation, and the most recent
in the fossil record worldwide. A row of prominent ulnar papilli or “quill knobs” on the ulna is our first clear evidence for
feather quills on a large dromaeosaurid forearm and impacts evolutionary reconstructions and functional morphology of such
derived, typically flight-related features. The presence of this new predator expands our record of theropod diversity in latest
Cretaceous Laramidia, and radically changes paleoecological reconstructions of the Hell Creek Formation.
Keywords: Maastrichtian, maniraptoran, Laramidia, flightless, ulnar papillae, paleoecology
