Atrociraptor
uh-TROSS-ih-RAP-tor
"savage robber"
- Lived
- 84 to 66 million years ago, Late Cretaceous
- Diet
- Carnivore
- Group
- Theropods, Dromaeosauridae
- Found in
- Canada
- Named by
- Currie and Varricchio 2004
Where its fossils were found
The evidence
Today
75 million years ago
Habitat
It lived in a river landscape in Alberta, recorded in the Horseshoe Canyon Formation. Regional neighbors included Albertosaurus, Edmontosaurus and Pachyrhinosaurus.
Field notes
About Atrociraptor
What it was like
Atrociraptor was a small, sharp-toothed dromaeosaurid, much smaller than large relatives such as Utahraptor. Its skull was noticeably deep for its size, and its teeth curved backward more strongly than in most of its relatives, hinting at a bite suited to bigger prey than its size alone would suggest. Like other dromaeosaurids, it likely carried a large, curved claw on each second toe and was covered in feathers.
Its world
Atrociraptor lived in what is now Alberta, Canada, during the Late Cretaceous, between about 84 and 66 million years ago. Its remains, five finds in total, come from the Horseshoe Canyon Formation.
It shared this world with large plant eaters such as Edmontosaurus and Pachyrhinosaurus, the tyrannosaur Albertosaurus, and other small predators including Troodon and Ornithomimus.
How it was found
Currie and Varricchio named Atrociraptor in 2004. It belongs to Dromaeosauridae, the family of sickle-clawed predators that also includes Velociraptor, Deinonychus, and Utahraptor. With five known finds, it is a modestly documented member of the group, and its exact relationships within Dromaeosauridae are still being worked out.
Field gallery
More views of Atrociraptor
Scenes reconstructed from the available fossil evidence.
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Lived alongside
Found in the same rock formations
A rock formation can hold fossils laid down millions of years apart, so not every animal here met Atrociraptor.
The evidence
The science behind Atrociraptor
Which parts of the picture come from its own bones, and which come from its relatives.
From its own fossils
- A partial skull preserves a short, deep snout and robust jaws.
- Its teeth lean strongly backward and have serrated cutting edges.
Borrowed from relatives
- The long tail, inward-facing arms and raised sickle claw are inferred from dromaeosaurs such as Deinonychus and Velociraptor.
- A feathered body and long arm feathers follow relatives such as Microraptor and Velociraptor.
Still unknown
- Its exact body size and proportions.
- The shape of the top of its skull and the color of its feathers.
- Whether it hunted alone or in groups.
Often drawn wrong
- A long, shallow snout misses the deep jaw shape preserved in its fossils.
- A bare, scaly body omits the feather covering inferred from its relatives.
- Its palms faced inward rather than downward.
Discovery timeline
- 2004Named itCurrie & Varricchio
- 2007Close relativeTurner, Makovicky & Norell
- 2011How it fedFowler et al.
Key papers
The research behind what we know of Atrociraptor
Named it
Named a dromaeosaur from a partial skull with a short, deep snout and strongly backward-leaning teeth.
A new dromaeosaurid from the Horseshoe Canyon Formation (Upper Cretaceous) of Alberta, Canada. Feathered Dragons. Indiana University Press, Bloomington.
No link available
Close relative
Found attachment points for long arm feathers in Velociraptor, supporting feathered arms in relatives such as Atrociraptor.
Feather quill knobs in the dinosaur Velociraptor. Science 317: 1721
Read the paper : Feather quill knobs in the dinosaur Velociraptor (opens in a new tab)How it fed
Proposed that Deinonychus used its enlarged foot claws to grip and pin prey, a possible feeding model for other dromaeosaurs.
The Predatory Ecology of Deinonychus and the Origin of Flapping in Birds. PLoS ONE 6: e28964
Read the paper : The Predatory Ecology of Deinonychus and the Origin of Flapping in Birds (opens in a new tab)
Close relatives
Other members of Dromaeosauridae
Sources: Wikidata