manatee vs sirenian mammal

manatee and sirenian mammal both are nouns.

Word	Noun	Adjective	Verb	Adverb
manatee	Yes	No	No	No
sirenian mammal	Yes	No	No	No

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

manatee: sirenian mammal of tropical coastal waters of America; the flat tail is rounded
sirenian mammal: any of two families of large herbivorous aquatic mammals with paddle-shaped tails and flipper-like forelimbs and no hind limbs

Other hypernyms of manatee include sea cow, sirenian.

manatee (noun)	sirenian mammal (noun)
sirenian mammal of tropical coastal waters of America; the flat tail is rounded	any of two families of large herbivorous aquatic mammals with paddle-shaped tails and flipper-like forelimbs and no hind limbs