genus Diceros vs mammal genus

genus Diceros and mammal genus both are nouns.

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

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

genus Diceros (noun)	mammal genus (noun)
most common species in Africa	a genus of mammals