Spinosauridae

Spinosauridae is a family of large, bipedal tetanuran theropod dinosaurs known from the Cretaceous of Africa, Europe, Asia, and South America. It is traditionally divided into two subfamilies: the Baryonychinae, which include smaller-bodied forms such as Baryonyx, Suchomimus, Ceratosuchops, and Riparovenator with slightly recurved, faintly serrated teeth; and the Spinosaurinae, which include Irritator, Ichthyovenator, Sigilmassasaurus, and the giant Spinosaurus, with straight, unserrated teeth and nostrils set even further back on the skull. Members are marked by long, low, narrow crocodile-like snouts whose tips fan out into a spoon-shaped rosette of enlarged teeth, retracted nostrils, and robust forelimbs ending in three-fingered hands with an enlarged first-finger claw. In many species the tall neural spines of the back vertebrae supported a skin- or fat-covered sail, most extreme in Spinosaurus. Direct fossil evidence and anatomical adaptations point to at least partially fish-eating, often semiaquatic habits, though spinosaurids also preyed on other dinosaurs and pterosaurs.