Aplysiidae Family of Sea Hares

Three Sea Hares of the Aplysiidae Family can be found in this website:

Phylogeny:  Sea Hares  of the Aplysiidae Family are members of the phylum Mollusca. They are in the class Gastropoda and the Herterobranchia subclass of “different-gilled snails”. They are in the Euthyneura infraclass,  which means they have two pairs of sensory head tentacles, with different shapes and functions. Sea Hares are in the order Aplysiida, which contains the superfamilies Akeroidea and Aplysioidea. The Aplysiidae Family is the only family in the Aplysioidea superfamily. The Aplysiidae Family contains ten genera and around eighty-three species. The name Aplysiidae comes from the Greek and Latin words meaning unwashed, possibly referring to the inability of these animals to hide in a shell.  They derive their common name from their rounded body outline and long projecting rhinophores attached to the head, which give them the shape of a sitting rabbit. They are known in Mexico as Vaquita Del Mar.

Morphology:  Sea Hares lack the external shell of most gastropods and instead have a small, flimsy, shell buried within the mantle. The mantle also covers the gills and other organs. They have one large exhalant siphon in the middle of the back and a smaller inhalant siphon in front of the shield. The rhinophores are chemosensory organs that detect “scent” in the water and water motion. Sea hares have wing-like flaps (parapodia) along their sides. These parapodia allow the animal a limited amount of swimming ability. Sea Hares have a large, relatively simple, and easily accessed nervous system that have made them good subjects for neurobiology studies. Sea Hares are perhaps the largest of all gastropods, reaching 99 cm (3 feet 3 inches) in length and 14 kg (30 lbs) in weight.

Distribution:  Sea Hares are generally found on soft substrates and vegetation.  Most are found in bays and in shallow coastal waters. The live from the intertidal zones to depths around 83 m (272 feet). Sea Hares are found worldwide in temperate to tropical seas. Fourteen species from the Aplysiidae Family are found in Mexican waters.

Reproduction: Sea Hares are hermaphrodites, possessing both male and female reproductive organs. Reproduction is sexual with internal fertilization. When mating, they usually form chains of several individuals, functioning as both male or females. The eggs are laid as a stringy mass, which can contain millions of embryos.

Ecosystem Roles:  Sea Hares are herbivores that consume brown, green and red algae, as well as sea grasses. Some species extract the pigment from the algae and use it as an ink that they secrete as a defense mechanism to avoid predation. Sea Hares are preyed on by fish, flatworms, lobsters, sea slugs, sea spiders, sea turtles, and starfish.