Vigilius is an extinct genus of brachyopid temnospondyl amphibian from the Triassic of Arizona. It is known from the single type species Vigilius wellesi. The holotype specimen of Vigilius is a skull labelled UCMP 36199. The skull was found in an area alongside Arizona State Route 64 overlooking the Grand Canyon. It came from a layer of the Early Triassic Moenkopi Formation. The skull was described by paleontologists Samuel Paul Welles and Richard Estes in 1969 and attributed to a new genus and species of brachyopid called Hadrokkosaurus bradyi. The holotype of Hadrokkosaurus was an isolated lower jaw. In 2000, paleontologists Anne Warren and Claudia Marsicano suggested that the lower jaw and skull represent two different species, as they were found over 160 kilometres (99 mi) apart and co