Allosaurids

Allosaurids are a family of carnivorous theropod dinosaurs within the larger clade Allosauroidea, known from the Middle to Late Jurassic. The best-known member is Allosaurus fragilis, described from North American fossils largely from the Morrison Formation. Fossils attributed to allosaurids have also been found in Europe and Asia, indicating a wide geographic distribution.

In anatomy, allosaurids were large predators with robust skulls and long jaws. They possessed sharp, serrated teeth and relatively light snouts. Their forelimbs were short with three-fingered hands and large claws, while the hind limbs were strong, suggesting capable movement for a large theropod.

Ecology and behavior: allosaurids were among the dominant predators in many Jurassic ecosystems, preying on sauropods and other dinosaurs, and possibly scavenging. Evidence from trackways and wear patterns on bones suggests active hunting and opportunistic feeding.

Geographic and temporal range: allosaurids lived primarily during the Middle to Late Jurassic, about 170 to 145 million years ago. They are best known from North America, but related forms are also described from Europe and Asia, indicating a broad distribution across Laurasia.

Taxonomy: the exact composition of Allosauridae varies with phylogenetic analyses. Allosaurus is the most securely placed member, with other close relatives sometimes assigned to different but related allosauroid groups. Ongoing research continues to clarify the relationships within Allosauroidea.