Mammalia - Perissodactyla - Equidae

Synonym: Calippus anatinus Quinn 1955

Belongs to Calippus according to C. S. Johnston 1937

Sister taxa: Calippus castilli, Calippus cerasinus, Calippus circulus, Calippus elachistus, Calippus hondurensis, Calippus maccartyi, Calippus martini, Calippus placidus, Calippus proplacidus

Type specimens:

• Calippus regulus: Its type locality is Grant Lease, which is in a Miocene terrestrial horizon in Texas
• Calippus anatinus: Its type locality is Buckner Ranch Site 1, which is in a Clarendonian terrestrial horizon in the Goliad Formation of Texas.

Ecology: ground dwelling grazer

Average measurements (in mm): P3 14.5 x 14.7, P4 14.5 x 14.7, M1 14.0 x 13.4, p3 14.7 x 8.5, p4 14.7 x 8.5, m1 14.3 x 6.9