Thelocactus rinconensis ssp. freudenbergeri (Haas) Mosco & Zanovello, CCI 7: 18 (1999).

Basionym: Thelocactus rinconensis var. freudenbergeri Haas, Kakt. and. Sukk. 43: 97 (1992).
Holotype: Freudenberger s. n. in Coll. Haas Nr. 157 (ZSS 9178).
Synonyms: Thelocactus lophothele ssp. freudenbergeri Matusz., Thelocactus 184 (2011).

Description
Stem single, depressed or globose, 8 cm tall, 15 cm wide. Ribs 21, distinct. Tubercles conical. Areoles without glands. Central spines 3-4, 40-100 mm long, ochre to greyish, straight or slightly curved, acicular. Radial spines 4-6, 15-40 mm long, ochre to greyish, straight, acicular. Flowers 50-60 mm wide, magenta. Seeds 2.3 x 1.6 mm, testa cells tabular with a verrucose surface sculpture.

Distribution
Mexico, Nuevo León, known only from the type locality near Grutas de Garcia, occurring in matorral xerofilo on limestone hills, at an elevation of about 900 metres above sea level. Its range lies within the Central Chihuahuan subregion of the Chihuahuan Desert ecoregion.

Comments
A nice subspecies that differs from the type for the presence of radial spines and the beautiful magenta flowers.