Ouranosaurus

Ouranosaurus was a distinctive iguanodontian dinosaur that roamed the river plains of northern Africa during the Early Cretaceous. It is instantly recognisable by the exceptionally tall neural spines running down its back and tail. These spines, which grew up to sixty centimetres in height, supported either a thin skin sail used for thermoregulation and visual signalling, or a thick, fatty hump for storing nutrition during drought. Reaching over seven metres in length, Ouranosaurus was a large herbivore that walked on all four limbs while browsing but could move bipedally when running. Its skull was long and flat with a broad snout and small thumb spikes on its hands, ideal for snipping riverbank vegetation alongside ancient crocodyliforms and spinosaurs.

Its back featured massive neural spines reaching up to sixty centimetres tall, forming a prominent sail or hump.

Where and when

Ouranosaurus lived in the Early Cretaceous, from 125 to 112 million years ago (Aptian-Albian age). Its remains come from Niger, in the Elrhaz Formation.

The numbers

Length 7.7 m (estimates run from 7 to 8.3 m). Mass about 2.4 t. Hip height about 2.6 m. That is 4.5 human-lengths, or 0.69 of a double-decker bus. These are estimates from near-complete skeleton; fields marked estimated by the site are length, mass, hip height.

Compare Ouranosaurus with a bus Place on the timeline