This name is a synonym of Melocactus harlowii (Britton & Rose) Vaupel.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 5108004) with original publication details: Acta Biol. Acad. Sci. Hung. 22(1–2): 137 1976.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:135547-1.
This name was in version 1 of The Plant List, record tro-5108004.