Dinosaur tail reveals gigantic swimming predator

A new fossil of one of the most unusual dinosaurs, Spinosaurus aegyptiacus, suggests it was a “river monster” powered by a fin-like tail. A new fossil found in Morocco has revealed long spines on the dinosaur’s tail that could have made it work like a giant fin. Hydrodynamic tests with plastic reconstructions of various tail shapes showed that the spinosaurus’s newt-like appendage would produce much more thrust than the tails of other dinosaurs. Spinosaurus aegyptiacus was probably even bigger than Tyrannosaurus rex.