Fellow's Nudibranch

Hiatodoris fellowsi

Hiatodoris fellowsi is a small nudibranch with an oval-shaped, firm white body, accented by black rhinophores and gills. This species can reach a maximum size of about 51 mm. It is often found under shaded cliffs and ledges, typically at depths ranging from 3 to 24 meters, although records indicate it can be found at depths shallower than 40 meters. Fellow's Nudibranch thrives in various locations throughout the Pacific Ocean, including the Hawaiian Islands and Henderson Island, where it feeds primarily on sponges. As a hermaphrodite, Hiatodoris fellowsi has both male and female reproductive organs. Its reproductive system features distinct ejaculatory and vaginal ducts, with a straight ejaculatory duct and a convoluted vas deferens. The species' unique anatomy includes a large, lobulate prostate gland and a radula that is simply hamate, measuring between 75 and 450 μm long. Encounters with this nudibranch during dives can be intriguing, as divers may observe its feeding behavior on sponges and its characteristic movement across rocky surfaces. While specific conservation status details are not provided, divers may find this species at various dive sites, making it a relatively accessible nudibranch to observe in its natural habitat.