Spinostropheus

Spinostropheus was a slender, medium-sized theropod dinosaur from the Middle Jurassic of what is now Niger. Originally discovered in the 1950s and assigned to the genus Elaphrosaurus, subsequent anatomical reviews by Paul Sereno and colleagues established that it represented a distinct genus of early ceratosaurian. Reaching roughly four metres in length, Spinostropheus possessed elongated cervical vertebrae bearing distinctive, complex processes for tendon and muscle attachments, which gave the animal its name. Built for agility, it likely relied on fast, bipedal locomotion to hunt small dinosaurs, lizards, and other small vertebrates across inland plains. Its fossils offer an important window into the early evolutionary radiation of ceratosaurs in Gondwana before the emergence of the massive abelisaurids.

Originally described as an African species of Elaphrosaurus, it was later identified as a distinct basal ceratosaur.

Where and when

Spinostropheus lived in the Middle Jurassic, from 167 to 161 million years ago (Bathonian-Callovian age). Its remains come from Niger, in the Tiourarén Formation.

The numbers

Length 4.2 m (estimates run from 3.8 to 4.5 m). Mass about 210 kg. Hip height about 1.3 m. That is 2.5 human-lengths, or 0.38 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, first ma, last ma, hip height.

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