It’s amazing to think that millions of years ago the Sahara was in fact a lush green tropical paradise, home to giant dinosaurs and crocodiles and nothing like the dusty desert we see.
At different geological depths were found fossil algae that confirm that 150-200 million years ago, during the Jurassic, Sahara was covered by an ancient sea, which was in some places 5,000m deep. From the sea, many fossils came, like ammonites (shelled squids), one meter long fishes from extinct groups and ancient huge sea reptiles. By 135 million years ago, dinosaurs roamed Sahara, like the 9m long carnivorous Afrovenator or the 22m long sauropod Jobaria.
In the era of the Spinosaurus, a vast river and swamp system stretched across North Africa, filled with lungfish, sharks and crocodilian creatures, as well as dinosaurs. Spinosaurus, floating like a crocodile to stalk prey, probably ate fish, ancient crocodiles, and anything else afloat.
Nizar Ibrahim, a University of Chicago vertebrate paleontologist and lead author of the 2014 study says a digital reconstruction of Spinosaurus bones tell a story of semi-aquatic adaptation. The creature’s skull sported small nostrils midway up the snout, perfect for breathing with the jaw submerged like a crocodile. Also similar to crocodiles, the tip of the snout possessed nerve and blood vessel channels, sensitive to sudden pressure changes in the water from fleeing prey.
Once prey was located, Spinosaurus’s large, backward-slanted and conical teeth made perfect rakes for catching fish.
Long powerful front arms brandished hooked claws to catch anything those teeth missed. The massive sail that ran along the Spinosaurus spine is the tallest such sails of any known dinosaur, at about 1.8 meters high. Most likely, the sail was a form of display to other spinosaurids, either a warning to rivals or a come-hither to potential mates, very visible when swimming but unseen by underwater prey, Ibrahim suggests. (Floro Mercene)