platyrhine vs platyrrhinian

platyrhine is not a noun while platyrrhinian is a noun.

Word	Noun	Adjective	Verb	Adverb
platyrhine	No	Yes	No	No
platyrrhinian	Yes	Yes	No	No

As adjectives, platyrhine and platyrrhinian are synonyms defined as:

platyrhine and platyrrhinian: of or related to New World monkeys having nostrils far apart or to people with broad noses

Other synonyms of platyrhine include broadnosed, platyrhinian, platyrrhine, platyrrhinic.

platyrhine (noun)	platyrrhinian (noun)
	hairy-faced arboreal monkeys having widely separated nostrils and long usually prehensile tails

platyrhine (adjective)	platyrrhinian (adjective)
of or related to New World monkeys having nostrils far apart or to people with broad noses	of or related to New World monkeys having nostrils far apart or to people with broad noses