Mazonia hungerfordi was named by Elias (1937). Its type specimen is USNM 125453, an exoskeleton, and it is a compression fossil. Its type locality is 6 miles northwest of Garnett, which is in a Kasimovian estuary/bay shale in the Stanton Formation of Kansas. It is the type species of Garnettius.

It was considered a nomen nudum by Elias (1936); it was recombined as Garnettius hungerfordi by Petrunkevitch (1953), Kjellesvig-Waering (1986), Dunlop et al. (2013).