The osteology of the postcranial skeleton of the holotype of Dubreuillosaurus valesdunensis (Allain, 2002) from the Middle Jurassic Calcaires de Caen Formation (Bathonian) is described here. In addition to previous phylogenetic analyses, characters of the caudal vertebrae show that Dubreuillosaurus, gen. nov., is distinct from Poekilopleuron. Some features of Dubreuillosaurus are unique among Spinosauroidea, including the medioventrally directed femoral head and the convex anterior surface of the distal end of the femur. A re-examination of the observations made by Eudes-Deslongchamps on Poekilopleuron suggests that megalosaurids were piscivorous to a certain extent.