Ornitholestes

Ornitholestes was a compact, fast-running carnivorous theropod that shared its Late Jurassic habitat with giants such as Allosaurus and Stegosaurus. Recovered from the rich sediments of Wyoming's Morrison Formation, it is known from a partial skull and skeleton. It possessed a relatively short, robust head, sharp recurved teeth, and grasping hands with elongated fingers well suited for snagging active prey. For most of the twentieth century, popular restorations gave Ornitholestes a tiny nasal horn, though careful preparation later demonstrated this was an illusion caused by damaged and displaced bone. Measuring roughly two metres long and weighing about as much as a medium dog, it was an agile hunter of early mammals, lizards, and hatchling dinosaurs. Its exact evolutionary placement remains debated, though it is usually classified as an early branch of the coelurosaurian lineage.

Long depicted with a small horn on its snout, modern re-examination showed this feature was merely crushed nasal bone.

Where and when

Ornitholestes lived in the Late Jurassic, from 154 to 150 million years ago (Kimmeridgian-Tithonian age). Its remains come from United States, in the Morrison Formation.

The numbers

Length 2.1 m (estimates run from 2 to 2.2 m). Mass about 13 kg. Hip height about 0.6 m. That is 1.2 human-lengths, or 0.19 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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