Megaraptoridae

Megaraptoridae is the derived family within Megaraptora, a group of carnivorous theropod dinosaurs noted for their powerfully built forelimbs and enormous hand claws. It encompasses the more advanced megaraptorans, including Megaraptor, Orkoraptor, Murusraptor, Aerosteon, and the Australian Australovenator, while excluding the basal-most members Fukuiraptor and Phuwiangvenator. Its members are set apart by a distinctive ulna that is T-shaped in cross section, formed by a thin, blade-like olecranon crest and a perpendicular ridge called the lateral tuberosity, and by thin, oval-sectioned claws bearing asymmetric grooves and a sharp lower edge. Most are known only from fragmentary remains, but collectively they were medium to large predators with slender, running-adapted limbs and heavily air-filled bones. They ranked among the apex predators of Late Cretaceous Gondwana, reaching their greatest diversity in Patagonia and also occurring in Australia.