Some regard this as a form of Aylostera haagei ssp. mudanensis, which itself is sometimes regarded as a separate species: A. mudanensis. Rausch states that the two are closely related. They are similar, but the distribution area of A. nazarenoensis is much further north.
Unfortunately the descriptions of both species are ambiguous in places and contradictory to additional notes and additional material, so the definitions are not clear-cut. Notes following the description state that A. nazarenoensis differs from A. mudanensis in that it has a darker orange flower, more prominent tubercles, and more central spines (although the Latin description states a single central spine!) Found to be distinctive enough to be given specific status by Mosti & Papini (2011).
The description is here.
Plants of this species in the collection include:
Aylostera nazarenoensis JO231
Aylostera nazarenoensis MN136
Aylostera nazarenoensis RH570
Aylostera nazarenoensis WR484