Ruvettus pretiosus vs gempylid

Ruvettus pretiosus and gempylid both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ruvettus pretiosus	Yes	No	No	No
gempylid	Yes	No	No	No

As nouns, gempylid is a hypernym of Ruvettus pretiosus; that is, gempylid is a word with a broader meaning than Ruvettus pretiosus:

Ruvettus pretiosus: very large deep-water snake mackerel
gempylid: snake mackerels; elongated marine fishes with oily flesh; resembles mackerels; found worldwide

Ruvettus pretiosus (noun)	gempylid (noun)
very large deep-water snake mackerel	snake mackerels; elongated marine fishes with oily flesh; resembles mackerels; found worldwide