Deltadromeus

Deltadromeus (meaning "river delta or change runner") is an extinct genus of controversial theropod dinosaur that lived in present-day Morocco during the mid-Cretaceous period. It was described by American paleontologist Paul Sereno and colleagues in 1996. The genus contains a single species, D. agilis, named based on an incomplete postcranial skeleton, the holotype specimen. However, some fossils from the Bahariya Formation of Egypt that were formerly referred to the theropod Bahariasaurus have been suggested to belong to Deltadromeus. The holotype specimen of Deltadromeus was unearthed by a joint expedition by the University of Chicago and the Service Géologique du Maroc in Errachidia Province, eastern Morocco in rock layers coming from the Gara Sbaa Formation of the Kem Kem Beds. This indicates that these fossils date to the Cenomanian stage of the Cretaceous period, 100-95 million years ago.

Deltadromeus was around in length and in weight based on the holotype. If the Egyptian remains do belong to Deltadromeus, this would make it among the longest known theropod genera at around , comparable to Tyrannosaurus. The forelimbs of Deltadromeus are relatively long for a theropod, being proportionately longer than those of taxa like Allosaurus. Deltadromeus also preserves gracile, slender, and relatively long hindlimbs, indicating it was cursorial. Its tail vertebrae have broad, quadrangular (spines emerging from the base of the vertebra) with (cavities) which would store pneumatic air sacs.