Acheroraptor

Acheroraptor was a predatory dromaeosaurid theropod that lived at the very end of the Cretaceous period in North America. Discovered in Montana's famed Hell Creek Formation, it is recognized from maxilla and dentary bones bearing teeth characterized by distinctive vertical ridges. Measuring roughly two metres long and weighing up to thirty kilograms, it was a medium-sized raptor with a slender, elongate snout. Phylogenetic analysis places Acheroraptor within the velociraptorines, making it a close North American relative of the Asian Velociraptor and Linheraptor. As an agile biped with sharp claws, acute senses, and likely a coat of plumage, it hunted small vertebrates and the juveniles of large herbivorous dinosaurs. It shared its environment with icons like Tyrannosaurus and Triceratops until the asteroid impact brought an end to non-avian dinosaurs.

It is the geologically youngest known dromaeosaurid from North America, surviving right up to the end-Cretaceous extinction event.

Where and when

Acheroraptor lived in the Late Cretaceous, from 67.2 to 66 million years ago (Maastrichtian age). Its remains come from United States, in the Hell Creek Formation.

The numbers

Length 2 m (estimates run from 1.8 to 2.2 m). Mass about 26 kg. Hip height about 0.7 m. That is 1.2 human-lengths, or 0.18 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.

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