pouched mammal vs metatherian

pouched mammal and metatherian both are nouns.

Word	Noun	Adjective	Verb	Adverb
pouched mammal	Yes	No	No	No
metatherian	Yes	No	No	No

As nouns, metatherian is a hypernym of pouched mammal; that is, metatherian is a word with a broader meaning than pouched mammal:

pouched mammal: mammals of which the females have a pouch (the marsupium) containing the teats where the young are fed and carried
metatherian: primitive pouched mammals found mainly in Australia and the Americas

pouched mammal (noun)	metatherian (noun)
mammals of which the females have a pouch (the marsupium) containing the teats where the young are fed and carried	primitive pouched mammals found mainly in Australia and the Americas