Deltadromeus

Deltadromeus is a large, lightly built carnivorous theropod recovered from the mid-Cretaceous Kem Kem Beds of Morocco. Estimated to have reached approximately eight metres in length, it was exceptionally gracile for its size. Its name reflects its long, slender leg bones, which indicate it was capable of impressive running speeds over the lush, ancient delta waterways it inhabited. Its evolutionary relationships have been debated; originally considered a coelurosaur, it is now widely classified as a derived ceratosaur within or close to the Noasauridae. The holotype skeleton lacks a skull, but the rest of the postcranial skeleton demonstrates unique adaptations for cursorial locomotion. It shared its rich ecosystem with colossal predators like Spinosaurus and Carcharodontosaurus, likely carving out a separate ecological niche hunting swift terrestrial prey.

Its exceptionally slender, elongate lower leg bones indicate it was among the fastest large theropods of the mid-Cretaceous.

Where and when

Deltadromeus lived in the Late Cretaceous, from 99.6 to 93.5 million years ago (Cenomanian age). Its remains come from Morocco, in the Kem Kem Beds.

The numbers

Length 8 m (estimates run from 7.5 to 8.5 m). Mass about 1.3 t. Hip height about 2.1 m. That is 4.7 human-lengths, or 0.71 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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