In 1860, Sixt Friedrich Jakob von Kapff at the Heslacher Wand near Stuttgart discovered the upper jaw bone of a large reptile.

[3] Later authors, such as Kapff himself, von Huene, Osborn, and Edwin H. Colbert, incorrectly attributed postcrania of the sauropodomorph dinosaur Efraasia to this species or genus and, as a result, it was thought to be a representative of a presumed group of carnivorous Prosauropoda or, alternatively, 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.

In 1985 and 1986, Peter Galton and Michael Benton independently showed that Teratosaurus is actually a rauisuchian, a type of non-dinosaurian large predatory archosaur, many of which walked on all fours, and lived alongside dinosaurs during the Late Triassic.

[7] Teratosaurus silesiacus, described in 2005 by Tomasz Sulej on the basis of a left maxilla,[8] was transferred to the genus Polonosuchus by Brussatte et al. in 2009.