A new fossil suggests that Spinosaurus aegyptiacus was a swimming predator powered by a fin-like tail, making it potentially unique amongst non-avian dinosaurs. The find comes after decades of debate on how much of its life Spinosaurus would have spent in the water, and how reliant they might have been on aquatic prey. Paleontologist Nizar Ibrahim has been working at the dig site in the Sahara and describes his amazement at the unexpected tail bones they found under the rock and sand.