genus Dasyatis vs fish genus

genus Dasyatis and fish genus both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus Dasyatis	Yes	No	No	No
fish genus	Yes	No	No	No

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

genus Dasyatis (noun)	fish genus (noun)
type genus of the Dasyatidae	any of various genus of fish