Mesadactylus ornithosphyos was named by
Jensen and Padian (1989). Its type specimen is BYU 2024, a set of vertebrae (synsacrum), and it is a 3D body fossil. Its type locality is
Dry Mesa Quarry (BYU), which is in a Kimmeridgian/Tithonian channel sandstone in the Morrison Formation of Colorado. It is the type species of
Mesadactylus.