platyrhinian vs platyrrhine

platyrhinian is not a noun while platyrrhine is a noun.

Word	Noun	Adjective	Verb	Adverb
platyrhinian	No	Yes	No	No
platyrrhine	Yes	Yes	No	No

As adjectives, platyrhinian and platyrrhine are synonyms defined as:

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

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

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

platyrhinian (adjective)	platyrrhine (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