Notocactus megalanthus H.Schloss. & Brederoo in Kakteen And. Sukk. 32: 157. 1981
Notocactus megalanthus in Kakteen And. Sukk. 32: 157. 1981
is basionym for Notocactus mammulosus var. megalanthus in Internoto 25: 110. 2004
is basionym for Ritterocactus megalanthus in Sukkulenty 2(2): 22. 1999