A new giant carnivorous dinosaur from the Cretaceous of Patagonia

Abstract

LARGE carnivorous animals, the top members of the trophic chain, are rare, and flesh-eating dinosaurs were rarer still. For years the only known giant theropods were Tyrannosaums rex¹ and the poorly known Deinocheirus mirificus², both from the Northern Hemisphere, but many important new dinosaurs have been dis-covered in the Southern Hemisphere during the past decade, con-siderably increasing our knowledge of ancient ecosystems. Here we report a new giant carnivorous dinosaur from the Upper Creta-ceous of northwestern Patagonia (Argentina). This new taxon, Giganotosaums carolinii gen. et. sp. nov., is characterized by aproportionally low skull, a reduced shoulder girdle, and robust vertebrae and hind limbs. It represents a primitive evolutionary iteration of large theropods, and provides an opportunity to exam-ine the Gondwanan dinosaur palaeocommunities and their relation-ships to those from Laurasia. Several characters place G. carolinii within the Tetanurae³, and closer to Neotetanurae⁴ than to Torvosauroidea⁴. G. carolinii is the largest theropod ever recorded from the Southern Hemisphere, and is probably the world's biggest predatory dinosaur, having a body 12.5 metres long and an estima-ted weight of 6 to 8 tonnes.