von Huene, 1932
The only known fossils of this genus are two ilia (BMNH R83) from Stonesfield Slate, Oxfordshire, England. From these samples, von Huene described the only species, I. incognitus, in 1932. Another species, I. clevelandi, was proposed in 1976 by Peter Galton, who assigned Stokesosaurus clevelandi to Iliosuchus, but this has not been followed. The Iliosuchus ilia have a supra–acetabular ridge on the surface, similar to tyrannosaurids and many other predatory dinosaurs belonging to the group Tetanurae, including Piatnitzkysaurus and Megalosaurus. Such incomplete material is inadequate for accurate classification; nonetheless, Iliosuchus has sometimes been considered a tyrannosaurid ancestor. This is unlikely to be correct as the bones cannot be distinguished from small individuals of Megalosaurus, a megalosaurid. Whatever the case, Iliosuchus is not diagnostic and is therefore dubious. If Iliosuchus incognitus is a tyrannosauroid, it would be the earliest one yet, preceding Guanlong, otherwise the earliest recognized tyrannosauroid, by several million years.