[2] The species Astrohippus ansae was originally described by W. D. Matthew and R. A. Stirton based on several cheek teeth found in the Coffee Ranch quarry, Hemphill County, Texas.

This quarry has produced the remains of six other equid genera including Dinohippus and Nannippus.

[3] Astrohippus stockii was described from the Yepomera locality in Chihuahua, Mexico, by J.F.

[1] The species Astrohippus albidens was named by O. Mooser in 1965 from Mexico, the taxon was reassigned to the genus Dinohippus in 1988 by T. S. Kelly and E. B.

[1] Both species of Astrohippus have been reported to occur in the Ocote Local Fauna of Guanajuato, Mexico by O. Mooser in 1973.