Hexabranchidae

Common Names

The Hexabranchidae family is commonly referred to as "Spanish Dancers," due to their elegant, undulating movements as they swim through the water. They are also known as "Blue Dragons," "Sea Butterflies," and "Blue Glaucus" in some regions.

Characteristics

Hexabranchids possess a range of striking characteristics that distinguish them from other nudibranchs. Some of these include:

• Brightly colored bodies: The most notable feature of these creatures is their vibrant coloration. They often exhibit a striking blue, purple, or orange color scheme, sometimes with intricate patterns and markings.
• Large, prominent gills: As their name suggests, they have six prominent, branched gills located on their backs, which they use for respiration.
• Flattened, flexible bodies: Hexabranchids have a flattened, ribbon-like body that allows them to move gracefully and efficiently through the water.
• Absence of a shell: Like all nudibranchs, Hexabranchids lack a shell, which makes them particularly vulnerable to predation.

Environments

Hexabranchidae are primarily found in tropical and subtropical waters of the Indo-Pacific region. They prefer shallow reefs and sandy bottoms, where they can access their primary food source: sea anemones.

Feeding Habits

Hexabranchidae are carnivores and specialize in feeding on sea anemones. They use their radula, a ribbon-like structure in their mouth, to scrape off the tissue of the anemone. The interesting part is that they are immune to the stinging nematocysts (poisonous cells) of the anemone, which they even absorb and utilize as defense mechanisms.

References

For further information on Hexabranchidae, you can refer to the following resources:

• World Register of Marine Species
• ResearchGate - "Hexabranchus sanguineus: A Study of Its Radula and Feeding Mechanism"