Deltadromeus

What it was like

Deltadromeus was a carnivorous theropod built for speed, with long, slender hind limbs and a light frame. Estimates put it at around 8.1 meters (27 feet) long, among the bigger theropods known from its region, though these figures come from an incomplete skeleton and could shift as more material turns up.

Its arms were unusually long for a theropod, longer in proportion than those of many of its relatives. Scientists still debate exactly what kind of theropod it was: some studies place it among the ceratosaurs, close to Noasaurus and Elaphrosaurus, while others have linked it to entirely different theropod groups. If the ceratosaur link is correct, Deltadromeus may have been a plant eater or omnivore rather than a strict hunter, unusual for a dinosaur this size.

Its world

Deltadromeus lived from about 101 to 94 million years ago, in the Late Cretaceous, across what are now Egypt, Algeria, and Morocco. Its bones come from the Baharîje and Gara Sbaa formations.

It shared its world with some of the largest predators ever known, including Spinosaurus and the disputed Bahariasaurus, as well as the giant sauropod Paralititan and the plant eater Rebbachisaurus.

How it was found

Sereno and colleagues named Deltadromeus in 1996, giving it the species name Deltadromeus agilis. About six fossil finds are known so far. Some bones from Egypt once assigned to the theropod Bahariasaurus have since been suggested to belong to Deltadromeus instead, though this connection is still debated, and some researchers even wonder whether Deltadromeus and Bahariasaurus are the same animal under two names.