ground sloth vs megatherian

ground sloth and megatherian both are nouns.

Word	Noun	Adjective	Verb	Adverb
ground sloth	Yes	No	No	No
megatherian	Yes	No	No	No

As nouns, megatherian is a hypernym of ground sloth; that is, megatherian is a word with a broader meaning than ground sloth:

ground sloth: gigantic extinct terrestrial sloth-like mammal of the Pliocene and Pleistocene in America
megatherian: a large extinct ground sloth

Other hypernyms of ground sloth include megatherian mammal, megatheriid.

ground sloth (noun)	megatherian (noun)
gigantic extinct terrestrial sloth-like mammal of the Pliocene and Pleistocene in America	a large extinct ground sloth