Rileyasuchus is a genus of phytosaur from the Rhaetian (Late Triassic) Magnesian Conglomerate of England.

It has a confusing history, being associated with the taxonomy of Palaeosaurus and Thecodontosaurus, and being a replacement name for a preoccupied genus (Rileya, which had already been used by Ashmead, and Howard both in 1888 for a hymenopteran).

[1][2] In 1902, Friedrich von Huene named the new genus for two vertebrae and a humerus from deposits in Bristol.

[6] Benton et al. (2000) indicated that the type specimen was actually a chimera composed of a phytosaur humerus and Thecodontosaurus vertebrae.

Rileya was named after palaeontologist and surgeon Henry Riley who helped to discover the first known fossils in Bristol in 1834.