Ouranosaurus sketch 1995

Sketch: Arnold Sciberras
Ouranosaurus (meaning "brave (monitor) lizard") was an unusual iguanodont that lived during the early Cretaceous, about 110 million years ago in what is now Africa. Ouranosaurus measured about 7 meters long (24 ft) and weighed about 4 tons. Two complete fossils were found in the Echkar (or El Rhaz) Formation, Gadoufaouna deposits, Agadez, Niger, in 1966 and the animal was named in 1976 by French paleontologist Philippe Taquet.
Ouranosaurus was once believed to have had a large sail on its back, supported by thick long spines, that spanned its entire back and tail, like Spinosaurus, a well-known meat-eating dinosaur that lived around the same time, and the older Dimetrodon of the Permian Period
In fact, the tall neural spines did not closely resemble those of sail-backs such as Dimetrodon. The supporting spines in a sailback become thinner distally, whereas in Ouranosaurus the spines actually become thicker distally. The spines were also bound together by tendons, which stiffened the back. Finally, the spine length peaks over the forelimbs. All of these features indicate that the dinosaur may have had a hump, resembling that of a bison or camel, rather than a sail. It could have been used as a source of nutrition during harsh conditions.