Ouranosaurus

Ouranosaurus nigeriensis is a large herbivorous dinosaur from the Early Cretaceous of Africa. It is an iguanodontian ornithopod, a group of beaked, plant-eating dinosaurs that includes later members like Iguanodon.

Fossils of Ouranosaurus were discovered in the Tenere region of Niger, in the Echkar Formation, and the genus and species were named by Philippe Taquet in 1979. The name Ouranosaurus combines a Greek root meaning sky or heaven with saurus, lizard, while nigeriensis refers to Niger.

Anatomically, Ouranosaurus is notable for a distinctive sail formed by elongated neural spines along its back. This feature gives it a unique silhouette among iguanodontians. It possessed a beaked mouth and dental batteries typical of the group, adapted for processing plant material. Estimates place it at about 7 to 9 meters (23 to 30 feet) in length and roughly 2 to 3 metric tons in weight. Like other ornithopods, it was likely capable of both quadrupedal and bipedal locomotion.

In terms of ecology, Ouranosaurus would have browsed on low-lying vegetation and used a beak-and-teeth system to shear plant matter. The function of the dorsal sail is debated, with hypotheses ranging from display to thermoregulation.

Systematically, Ouranosaurus is placed within the Ornithopoda, specifically among the iguanodontians, and helps illuminate the diversity of Early Cretaceous dinosaur faunas in Gondwana. Its discovery contributed to understanding the geographic distribution and morphological variety of early iguanodontians in Africa.