Clethrionomys vs mammal genus

Clethrionomys and mammal genus both are nouns.

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

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

Clethrionomys: a genus of Cricetidae containing the red-backed voles (Clethrionomys)
mammal genus: a genus of mammals

Clethrionomys (noun)	mammal genus (noun)
a genus of Cricetidae containing the red-backed voles (Clethrionomys)	a genus of mammals