Camposaurus

Camposaurus was an agile, slender meat-eating dinosaur that roamed south-western North America during the Late Triassic period. Discovered in Arizona within the colourful layers of the Chinle Formation, it is known primarily from fossilised partial hindlimbs, notably fused lower leg bones. Despite the modest nature of its remains, detailed anatomical restudy has affirmed its validity as a distinct member of the coelophysid family. In life, Camposaurus probably measured between two and three metres in length and weighed roughly as much as a medium dog. It was built for speed, relying on long, slender legs to chase down nimble prey including early reptiles, sphenodontians, and small synapsids. Because its fossils date back over 210 million years, Camposaurus is recognised by paleontologists as one of the oldest known neotheropods, providing critical evidence regarding the early radiation and spread of predatory dinosaurs across the ancient supercontinent Pangaea.

A 2011 re-evaluation established Camposaurus as the oldest known confirmed neotheropod dinosaur.

Where and when

Camposaurus lived in the Late Triassic, from 220 to 210 million years ago (Norian age). Its remains come from United States, in the Chinle Formation.

The numbers

Length 2.5 m (estimates run from 2 to 3 m). Mass about 21 kg. Hip height about 0.8 m. That is 1.5 human-lengths, or 0.22 of a double-decker bus. These are estimates from fragmentary remains; fields marked estimated by the site are length, mass, first ma, last ma, hip height.

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