Phocoena sinus vs porpoise

Phocoena sinus and porpoise both are nouns.

Word	Noun	Adjective	Verb	Adverb
Phocoena sinus	Yes	No	No	No
porpoise	Yes	No	No	No

As nouns, porpoise is a hypernym of Phocoena sinus; that is, porpoise is a word with a broader meaning than Phocoena sinus:

Phocoena sinus: a short porpoise that lives in the Gulf of California; an endangered species
porpoise: any of several small gregarious cetacean mammals having a blunt snout and many teeth

Phocoena sinus (noun)	porpoise (noun)
a short porpoise that lives in the Gulf of California; an endangered species	any of several small gregarious cetacean mammals having a blunt snout and many teeth