The type specimen (IVPP V. 790) was fragmentary, disordered, and not excavated in a technical way. Material included five dorsal vertebrae, 30 caudal vertebrae, rib fragments, dorsal neural spines, and chevrons. Fourteen neck vertebrae were preserved, but none were complete. Young noted that some neck vertebrae might have been missing, and estimated the whole neck at . Limb material included; two pieces of a femur, a complete tibia, fibula, astragalus, metatarsals, phalanges, and claws. The skull, forelimbs and pelvic girdle were missing. "M. constructus" has been estimated around in length with a mass of .