What is Spinosaurus?

The Spinosaurus was most closely related to other Spinosauridae, such as Baryonyx. The next largest group they belonged to was the Megalosauria, such as Megalosaurus, and then theropods, which include bipedal, lizard-hipped, and mostly carnivorous dinosaurs, ranging from Tyrannosaurus to Velociraptor. Today, the closest living relatives of Spinosaurus are the only surviving theropods, the birds. Ironically, even though non-avian dinosaurs died out, the birds have diversified into nearly 10,000 known species, making them the second most diverse group of vertebrates in the world today after the perciform fish.