soft-shell clam vs Mya arenaria

soft-shell clam and Mya arenaria both are nouns.

Word	Noun	Adjective	Verb	Adverb
soft-shell clam	Yes	No	No	No
Mya arenaria	Yes	No	No	No

As nouns, soft-shell clam and Mya arenaria are synonyms defined as:

soft-shell clam and Mya arenaria: an edible clam with thin oval-shaped shell found in coastal regions of the United States and Europe

Other synonyms of soft-shell clam include long-neck clam, steamer, steamer clam.

soft-shell clam (noun)	Mya arenaria (noun)
an edible clam with thin oval-shaped shell found in coastal regions of the United States and Europe	an edible clam with thin oval-shaped shell found in coastal regions of the United States and Europe
a clam that is usually steamed in the shell