Millions of years ago the Sahara Desert was once an ocean teaming with life and the most feared creature of them all was the Spinosaurus Aegypatiacus. A recent discovery of a fossil of the creature's tail confirms that there once were dinosaurs that lived and hunted underwater.This river monster hunted in the water with its six-inch teeth and a strong fin-like tail. A fossil of one of these tails was recently found in Morocco and belonged to what can only be classified as a juvenile spinosaurus. These dinosaurs would have normally reached up to 50 feet and weighed 20 tonnes but the bone discovered revealed this was an adolescent, weighing only 4 tonnes at around 35 feet.Researchers believe that in their adulthood, spinosaurus' would have had no natural predators, topping the food chain. However, youngsters and adolescents would have been at risk due to the appetite of large fish and prehistoric crocodiles. While you may be thinking 'what about the ichthyosaurus?' scientists have known that this creature lived underwater all along. Well... although the ichthyosaurus was one of many reptiles that mastered life in the water it was not classified as a dinosaur.The newly discovered tail is a breakthrough for scientists. Dr David Unwin a Reader in Palaeobiology at the University of Leicester who was also involved in the research stated:The Spinosaurus' fin-like tail is a game changing discovery for us that fundamentally alters our understanding of how this dinosaur lived and hunted – it was actually a "river-monster." As well as its tail, many other features of this dinosaur, such as the high position of the nostrils, heavy bones, short legs, and paddle-like feet point to a life spent in the water rather than on land.The site where the discovery was made is also teaming with other fossils and is a known hotbed among researchers and has this spinosaurus tail is the first to found in a long time. Professor David Martill, who also took part in the research claimed:This fossil site has been incredible. This is the first Spinosaurus skeleton to be found for over a hundred years. It is also one of the few associated dinosaurs skeletons ever to be found in the Kem Kem rocks. Every time we look at this dinosaur we discover something fascinating about it. Martill also stated that was one question still burning in the minds of all spinosaurus enthusiasts:One thing that still puzzles me though, is why only Spinosaurus became aquatic among the dinosaurs. Why are there no aquatic iguanodons, or stegosaurs.