Lamellibranchia vs class Pelecypoda

Lamellibranchia and class Pelecypoda both are nouns.

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

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

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

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