Anne's Phyllidiopsis

Phyllidiopsis annae

Phyllidiopsis annae is a small nudibranch that typically grows to about 15 mm in length. It features a blue dorsum adorned with four longitudinal black lines, which are interspersed with raised ridges. The area between the outer black lines and the mantle's edge is marked by black spots. Its rhinophores are black, distinguishing it from similar species like Phyllidiopsis xishaensis, which has white rhinophores, and Phyllidiopsis phiphiensis, which has only three black lines instead of four. This species was originally described from Phi Phi Island in southern Thailand and has been reported in various locations across the Indo-West Pacific, including Indonesia, Papua New Guinea, and Vietnam. It is typically found in shallow waters, with 98% of recorded occurrences at depths shallower than 40 meters, and 90% under 30 meters, making it a common sight for divers exploring coral reefs and other shallow marine environments. Anne's Phyllidiopsis feeds primarily on sponges, and like other nudibranchs, it is a simultaneous hermaphrodite. During mating, individuals engage in a unique behavior where they dart their reproductive organs toward each other, determining which will act as the male and which as the female. Eggs are laid on a substrate, developing into planktonic larvae before maturing into adults. The conservation status of Phyllidiopsis annae has not been evaluated, but it is recorded at many dive sites, indicating it may be relatively common in its habitat. Divers may encounter this species while exploring the ecosystems of tropical waters, often observing its distinctive coloration and patterns against the backdrop of the reef.