Aztekium ritteri (Boed.) Boed. in Monatsschr. Deutsch. Kakteen-Ges. 1: 52. 1929 sec. Hernández & Gómez-Hinostrosa 2011
- ≡Echinocactus ritteri Boed. in Z. Sukkulentenk.: 305. 1928 syn. sec. Guzmán Cruz & al. 2003
- =Aztekium ritteri var. rotundum Šnicer & Kunte in Kaktusy (Brno) Special 1: 20. 2019 syn. sec. POWO 2017+