 The genus is currently monotypic, with the type and only species being "M. arduini".The species was originally named in 1880, although it was assigned to the genus "Crocodilius" (now spelled "Crocodylus").The genus was first erected by paleontologist Charles C. Mook in 1955 along with the tomistomine genus "Kentisuchus", which was also first classified as "Crocodilius".