Thorunna furtiva

Thorunna furtiva is a species of sea slug characterized by its white mantle adorned with a thin orange-yellow line along the edge. This distinctive coloration helps divers identify it among other nudibranchs. Originally described from Camiguin in Luzon, Philippines, this species is found throughout the western tropical Indo-Pacific Ocean, often inhabiting benthic environments such as coral reefs and rocky areas. It typically resides at depths shallower than 40 meters, with the majority of sightings occurring at depths around 20 meters or less. As a simultaneous hermaphrodite, Thorunna furtiva engages in a unique mating behavior where individuals extend their penises toward each other, with the dominant individual penetrating the body wall of the other. Eggs are laid on substrates, where they develop into a planktonic veliger larval stage before maturing into adults. Encounters with this nudibranch during a dive can be intriguing, as divers observe its slow movements and distinctive coloration against the backdrop of the reef. Currently, the IUCN Red List has not evaluated the conservation status of Thorunna furtiva, leaving its population status uncertain. However, divers should always be mindful of their impact on marine ecosystems and the species that inhabit them.