Actiosaurus (meaning "coast lizard") is an extinct genus of reptile first described by Henri Sauvage in 1883[1] from Antully bonebed, Autun (Triassic of France). The type species is A. gaudryi (commonly misspelled A. gaudrii after Boulenger[2]). Little is known of it, and it is considered a nomen dubium. Actiosaurus was originally described as a dinosaur in 1883 and was reinterpreted as an ichthyosaur in 1908. Actiosaurus may instead represent the remains of a choristodere.[3] Fischer et al. (2014) considered A. gaudryi to be a species inquirenda, and noted the similarity of its bones to the limb bones of choristoderes.[4]