The single spicies,C.solus is based on a axis with articulated axial intercentrum; the specimen appears to be lost. This axis resembles that of Allosaurus fragillis in the position of the upper pleurocoel, in having an axial intercentrum cylindrical (rathet than tapered) in ventral view, an axial intercentrum less than twice the length of the axial intercentrum, and a broad neural canal. These are apomorphies shared with Allosaurus fragillis and suggest that Composuchus is an allosaurid. Classified in the same family as Compsognathus.