metazoan vs fauna

metazoan and fauna both are nouns.

Word	Noun	Adjective	Verb	Adverb
metazoan	Yes	No	No	No
fauna	Yes	No	No	No

As nouns, fauna is a hypernym of metazoan; that is, fauna is a word with a broader meaning than metazoan:

metazoan: any animal of the subkingdom Metazoa; all animals except protozoans and sponges
fauna: a living organism characterized by voluntary movement

Other hypernyms of metazoan include animal, animate being, beast, brute, creature.

metazoan (noun)	fauna (noun)
any animal of the subkingdom Metazoa; all animals except protozoans and sponges	a living organism characterized by voluntary movement
	all the animal life in a particular region or period