Bivalvia vs class Lamellibranchia

Bivalvia and class Lamellibranchia both are nouns.

Word	Noun	Adjective	Verb	Adverb
Bivalvia	Yes	No	No	No
class Lamellibranchia	Yes	No	No	No

As nouns, Bivalvia and class Lamellibranchia are synonyms defined as:

Other synonyms of Bivalvia include class Bivalvia, class Pelecypoda, Lamellibranchia.

Bivalvia (noun)	class Lamellibranchia (noun)
oysters, clams, scallops, mussels	oysters, clams, scallops, mussels