eohippus vs Equus caballus

eohippus and Equus caballus both are nouns.

Word	Noun	Adjective	Verb	Adverb
eohippus	Yes	No	No	No
Equus caballus	Yes	No	No	No

As nouns, Equus caballus is a hypernym of eohippus; that is, Equus caballus is a word with a broader meaning than eohippus:

eohippus: earliest horse; extinct primitive dog-sized four-toed Eocene animal
Equus caballus: solid-hoofed herbivorous quadruped domesticated since prehistoric times

Other hypernyms of eohippus include horse.

eohippus (noun)	Equus caballus (noun)
earliest horse; extinct primitive dog-sized four-toed Eocene animal	solid-hoofed herbivorous quadruped domesticated since prehistoric times