Sirenia vs animal order

Sirenia and animal order both are nouns.

Word	Noun	Adjective	Verb	Adverb
Sirenia	Yes	No	No	No
animal order	Yes	No	No	No

As nouns, animal order is a hypernym of Sirenia; that is, animal order is a word with a broader meaning than Sirenia:

Sirenia (noun)	animal order (noun)
an animal order including: manatees, dugongs, Steller's sea cow	the order of animals