Spinosauridae is a family of specialized theropod dinosaurs. Members of this family were large, bipedal predators with elongated, crocodile-like skulls, sporting conical teeth with no or only very tiny serrations. The front dentary teeth fanned out, giving the animal a characteristic look. The name of this family alludes to the typically conspicuous sail-like structure protruding from the back of species in the type genus, Spinosaurus. The purpose of the sail is disputed, whereas popular explanations are that it may have served as a thermoregulator, a threat display, or as a sexual display during courtship, some palaeontologists rather interpret the neural spine elongation in Spinosaurus as a support of a muscular/fatty hump.