Hippocampus is the Latin name for which marine creature?

The story behind the answer

Hippocampus is the Latinized genus name for seahorses. It comes from Greek hippos (horse) and kampos (sea monster), fitting their horse-like heads and marine life. All seahorses belong to the genus Hippocampus in the pipefish family (Syngnathidae).

Memorable facts: seahorses are among the few animals where males get “pregnant”—females place eggs in the male’s brood pouch, and he carries them until birth. A handy mnemonic is “hippo = horse” and “campus by the sea,” so Hippocampus means horse of the sea. Bonus link: the hippocampus in the brain is named for its seahorse-like shape.