genus Arvicola vs mammal genus

genus Arvicola and mammal genus both are nouns.

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

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

genus Arvicola (noun)	mammal genus (noun)
in some classifications considered synonymous with Microtus	a genus of mammals