Teratosaurus

Teratosaurus (Gr. teras "monster" + sauros "lizard") was a genus of rauisuchian known from the Triassic Stubensandstein (Löwenstein Formation - Norian age) of Germany. The type specimen was described by von Meyer on the basis of a left maxilla (upper jaw bone) with large teeth, which he declared to be distinct from Belodon. Later authors, such as von Huene, Osborn, and Edwin H. Colbert, incorrectly attributed postcrania of the sauropodomorph dinosaur Efraasia to this species, and as a result it was thought to be a very primitive theropod. Following this lead, many popular books in the 20th century depicted "Teratosaurs" as the earliest sort of large bodied meat-eating dinosaur, walking on two legs and preying on the prosauropods of its day. It was thought by many to be a Triassic ancestor to the carnosaurs of the Jurassic.

In 1985 and 1986 Peter Galton and Michael Benton independently showed that Teratosaurus is actually a nondinosaurian rauisuchian, a type of large predatory archosaur which lived alongside dinosaurs during the Late Triassic.

T. silesiacus, described in 2005 by Tomasz Sulej, was transferred to genus Polonosuchus by Brussatte et al. in 2009.