Spinosauridae is a family of specialised
theropod dinosaurs. Members of this family were large
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; while 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.