Archosauria vs subclass Archosauria

Archosauria and subclass Archosauria both are nouns.

Word	Noun	Adjective	Verb	Adverb
Archosauria	Yes	No	No	No
subclass Archosauria	Yes	No	No	No

As nouns, Archosauria and subclass Archosauria are synonyms defined as:

Archosauria and subclass Archosauria: a large subclass of diapsid reptiles including: crocodiles, alligators, dinosaurs, pterosaurs, plesiosaurs, ichthyosaurs, thecodonts

Archosauria (noun)	subclass Archosauria (noun)
a large subclass of diapsid reptiles including: crocodiles, alligators, dinosaurs, pterosaurs, plesiosaurs, ichthyosaurs, thecodonts	a large subclass of diapsid reptiles including: crocodiles, alligators, dinosaurs, pterosaurs, plesiosaurs, ichthyosaurs, thecodonts