Marginocephalia vs marginocephalian

Marginocephalia and marginocephalian both are nouns.

Word	Noun	Adjective	Verb	Adverb
Marginocephalia	Yes	No	No	No
marginocephalian	Yes	No	No	No

As nouns, Marginocephalia and marginocephalian are synonyms defined as:

Marginocephalia and marginocephalian: includes boneheaded (pachycephalosaurs) and horned (ceratopsian) dinosaurs

Other synonyms of Marginocephalia include suborder Marginocephalia.

Marginocephalia (noun)	marginocephalian (noun)
includes boneheaded (pachycephalosaurs) and horned (ceratopsian) dinosaurs	includes boneheaded (pachycephalosaurs) and horned (ceratopsian) dinosaurs