A tyrannosauroid dinosaur from the Upper Jurassic of Portugal

Abstract

Fragmentary theropod remains from the Upper Jurassic (Kimmeridgian) of Guimarota, Portugal, represent a new taxon of theropod dinosaurs, Aviatyrannis jurassica gen. et sp. nov. Together with Stokesosaurus from the Morrison Formation of North America, Aviatyrannis represents the oldest known tyrannosauroid, indicating that tyrannosauroid origins may be found in the Middle-Late Jurassic of Europe/North America. Furthermore, current evidence suggests that early tyrannosaurs were rather small animals, which is in general accordance with their origin amongst the generally rather small coelurosaurs.