Fammillaria flavihamata
Reported from Aguascalientes. this is considered by the Fitz Maurices to be synonymous with M.mercadensis, by Hunt with M.rettigiana.
Either way it seems to be dubiously indentifiable now, with no clear locality cited.
Mammillaria - John Pilbeam pag.326
Mammillaria flavihamata
From "Ento" Ennio Toso collection - Savona
Mammillaria flavihamata
From "Ento" Ennio Toso collection - Savona