stone crab vs Menippe mercenaria

stone crab and Menippe mercenaria both are nouns.

Word	Noun	Adjective	Verb	Adverb
stone crab	Yes	No	No	No
Menippe mercenaria	Yes	No	No	No

As nouns, stone crab and Menippe mercenaria are synonyms defined as:

stone crab and Menippe mercenaria: large edible crab of the southern coast of the United States (particularly Florida)

stone crab (noun)	Menippe mercenaria (noun)
large edible crab of the southern coast of the United States (particularly Florida)	large edible crab of the southern coast of the United States (particularly Florida)
pale flesh with delicate texture and flavor; found in Florida but now very rare