Dinosaurs did exist in what is now Nigeria, based on fossil evidence.
The Dukamaje Formation, which spans parts of Nigeria and Niger, is a geological formation dating back to the Late Cretaceous period.
Fossils recovered from this formation include dinosaur remains, as well as a wealth of mosasaur fossils, particularly from the area around Mount Dukamaje.
While dinosaur fossils in Nigeria are rare compared to other regions, discoveries have been reported, including some dinosaur bones found in areas such as Mowe in Lagos.
However, most of the well-studied and prominent dinosaur discoveries in the region come from Niger, which shares a similar geological and paleontological history with northern Nigeria.
For example, the famous sauropod Jobaria tiguidensis and the predator Afrovenator were discovered in Niger.
Nevertheless, the geological formations and fossil beds in southern Niger and northern Nigeria are closely related, suggesting that similar dinosaur species would have lived across this region during the Cretaceous.
In summary, while dinosaur fossils in Nigeria are less common than in Niger, there is clear evidence that dinosaurs did inhabit what is now Nigeria during the Late Cretaceous. Several fossils have been found in the country.