mammalian vs Mammalia

mammalian and Mammalia both are nouns.

Word	Noun	Adjective	Verb	Adverb
mammalian	Yes	Yes	No	No
Mammalia	Yes	No	No	No

mammalian (noun)	Mammalia (noun)
any warm-blooded vertebrate having the skin more or less covered with hair; young are born alive except for the small subclass of monotremes and nourished with milk	warm-blooded vertebrates characterized by mammary glands in the female

mammalian (adjective)	Mammalia (adjective)
of or relating to the class Mammalia