Castoroides vs mammal genus

Castoroides and mammal genus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Castoroides	Yes	No	No	No
mammal genus	Yes	No	No	No

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

Castoroides: extinct beavers of the Pleistocene; of eastern and southern United States
mammal genus: a genus of mammals

Castoroides (noun)	mammal genus (noun)
extinct beavers of the Pleistocene; of eastern and southern United States	a genus of mammals