Elrhazosaurus (Basal Iguanodontian)

Iguanodontian dinosaurs from the Early Cretaceous of Niger, specifically within the Elrhaz Formation (Gadoufaoua deposits), include the prominent sail-backed Ouranosaurus nigeriensis and the heavily built Lurdusaurus arenatus. Another basal iguanodontian, Elrhazosaurus nigeriensis, is known from isolated fossils found in the region. 

Ouranosaurus nigeriensis: Named by Philippe Taquet in 1976, this 7–8.3 meter long herbivore is known for the, likely, heat-regulating or display-oriented sail on its back formed by long neural spines.

Lurdusaurus arenatus: Described as having a "massively-constructed" body, this iguanodontian had a unique, almost sloth-like body form compared to other members of its group.

Elrhazosaurus nigeriensis: Originally thought to be a species of Valdosaurus, this basal iguanodontian is known from fragmentary remains. 
These dinosaurs thrived in what is now the Sahara Desert during the Aptian stage (approx. 115–105 million years ago).