Astrophytum coahuilense was dercribed from Dr. Heinrich MÖLLER at the year 1927 as Echinocactus myriostigma subspecies coahuilense.
Regrouping some times later from Dr. KAYSER to Astrophytum coahuilense.
The habitus of the genus looks like Astrophytum myriostigma. But if we view the fruit, flowers and woolly flecks so the differences between the to genus become visible.
Also crossbreeding are fruitless.