This name is a synonym of Gymnocalycium pflanzii subsp. zegarrae (Cárdenas) G.J.Charles.
The record derives from WCSP (in review)
(data supplied on 2012-03-23)
which reports it as a synonym with original publication details: Gymnocalycium 13: 355 2000.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:1147922-2.
This name was in version 1 of The Plant List, record kew-2835882, and has not been changed.