Hexabranchus Explained

Hexabranchidae is a family of colourful nudibranchs (often called "sea slugs") which contains only a single genus, Hexabranchus, with six species.

This family is one of the many families of dorid nudibranchs in the suborder Doridina, named after Doris, who was a sea nymph in ancient Greek mythology.

The genus contains one of the largest known species of nudibranch in the world, H. giganteus, which grows up to or exceeding 50 cm in length.^{[1] [2]} Hexabranchus sanguineus is known to use chemical defenses derived from the sponge it eats and use the chemical compounds to defend itself from potential fish predators.^[3]

Species

There are six species within the genus Hexabranchus:

• Hexabranchus aureomarginatus Ostergaard, 1955
• Hexabranchus giganteus Tibiriçá, Pola & Cervera, 2023
• Hexabranchus lacer (Cuvier, 1804)
• Hexabranchus morsomus Ev. Marcus & Er. Marcus, 1962
• Hexabranchus sandwichensis Gray, 1850
• Hexabranchus sanguineus (Ruppell & Leuckart, 1828) - synonym: Hexabranchus praetextus Ehrenberg, 1828 - type species^[4]

Notes and References

1. Tibiriçá, Y.; Pola, M.; Pittman, C.; Gosliner, T. M.; Malaquias, M. A.; Cervera, J. L. (2023). A Spanish dancer? No! A troupe of dancers: a review of the family Hexabranchidae Bergh, 1891 (Gastropoda, Heterobranchia, Nudibranchia). Organisms Diversity & Evolution.
2. Web site: The Sea Slug Forum - Hexabranchus sanguineus. 15 July 2010.
3. Defensive chemicals of the Spanish Dancer nudibranch, Hexabranchus sanguineus, and its egg ribbons: Macrolides derived from a sponge diet. Pawlik. JR. 1988. Journal of Experimental Marine Biology and Ecology. 10.1016/0022-0981(88)90225-0. 119. 2. 99–109. etal.
4. Valdés Á. (2002). "How many species of Hexabranchus (Opisthobranchia : Dorididae) are there?". Molluscan Research 22(3): 289-301., PDF.