genus Lutra vs mammal genus

genus Lutra and mammal genus both are nouns.

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

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

genus Lutra: in some classifications considered a genus of the subfamily Lutrinae
mammal genus: a genus of mammals

genus Lutra (noun)	mammal genus (noun)
in some classifications considered a genus of the subfamily Lutrinae	a genus of mammals