Atrociraptor

Atrociraptor was a distinctive small predator that roamed western Canada during the early Maastrichtian stage of the Late Cretaceous. Uncovered in the Horseshoe Canyon Formation of Alberta, it is known from partial upper and lower jaws and isolated teeth. Reaching roughly two metres in length and weighing around twenty kilograms, it was comparable in stature to its relative Dromaeosaurus. However, Atrociraptor had a noticeably deeper and shorter snout than many other dromaeosaurs, paired with teeth that were remarkably isodont and angled backwards. This specialized cranial architecture suggests an adaptation for delivering forceful, damaging bites rather than the slashing tactics employed by narrow-snouted species. Likely coated in feathers and moving swiftly on two legs, Atrociraptor probably targeted juvenile dinosaurs, mammals, and other small vertebrates across ancient floodplains and forested river networks.

Its snout was unusually short and deep, with strongly angled teeth suggesting a distinct, specialized biting technique.

Where and when

Atrociraptor lived in the Late Cretaceous, from 72 to 68 million years ago (Maastrichtian age). Its remains come from Canada, in the Horseshoe Canyon Formation.

The numbers

Length 1.9 m (estimates run from 1.8 to 2 m). Mass about 19 kg. Hip height about 0.6 m. That is 1.1 human-lengths, or 0.17 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.

Compare Atrociraptor with a bus Place on the timeline