As nouns,
mantis crab is a hyponym of
stomatopod crustacean; that is, mantis crab is a
word with a more specific, narrower meaning than
stomatopod crustacean:
stomatopod crustacean: a kind of crustacean
mantis crab: tropical marine burrowing crustaceans with large grasping appendages
Other hyponyms of stomatopod crustacean include
mantis shrimp.