Pterocnemia vs bird genus

Pterocnemia and bird genus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pterocnemia	Yes	No	No	No
bird genus	Yes	No	No	No

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

Pterocnemia (noun)	bird genus (noun)
a genus of birds of the family Rheidae	a genus of birds