White-Spotted Yellow Wart Slug

Phyllidia flava

Phyllidia flava is a distinctive sea slug that can be recognized by its bright yellow coloration adorned with white spots. This nudibranch belongs to the family Phyllidiidae and is the only species of its kind known to inhabit the Mediterranean Sea. Divers can spot this species in various underwater environments, particularly in demersal zones where it resides among rocky substrates and reefs. Its typical habitat includes coral reefs and rocky reefs, making it a common sight for divers exploring these areas. In terms of behavior, Phyllidia flava is a simultaneous hermaphrodite, meaning individuals possess both male and female reproductive organs. During mating, two slugs engage in a unique courtship ritual where they extend their reproductive organs towards each other, and the dominant individual penetrates the body wall of the other. This reproductive strategy leads to the deposition of eggs on the substrate, where they develop into a planktonic larval stage before maturing into adults. Encounters with this species during dives can be interesting, as they often move slowly across the seafloor, allowing divers ample opportunity to observe their unique morphology and behaviors. While Phyllidia flava is not currently evaluated by the IUCN, it is generally considered harmless to humans, and divers can appreciate its presence without concern for their safety.