The captivating Dermatobranchus ornatus is a species of sea slug, a fascinating nudibranch and a marine gastropod mollusc belonging to the family Arminidae. Growing up to 80 mm (3.1 inches) in length, this strikingly patterned creature is a common sight across the Indo-Pacific, though spotting one on the reefs around Hurghada in the 🌊 Red Sea is always a special delight for divers.
Its body is typically a pristine white, adorned with numerous large, round tubercles that can vary significantly in colouration. While some specimens display uncoloured tubercles, they are often capped with vibrant red or orange rings, or appear as flat-topped orange structures or raised orange rings. Adding to its distinctive appearance, the mantle and oral veil frequently feature a striking orange border.
Unlike many other sea slugs that graze on sponges, D. ornatus has a very specific and impactful diet: gorgonian soft corals. It's a remarkably efficient feeder, often stripping the living tissue completely from the coral's skeletal framework. This specialized diet also serves a clever defensive purpose. Dermatobranchus ornatus bio-accumulates distasteful, toxic chemicals from its soft-coral prey. These potent metabolites are stored in specialized glands nestled along its brightly coloured mantle edge, turning the slug into an unpalatable meal for potential predators. This vivid coloration acts as a clear warning sign to any hungry fish.
First described from the 🇵🇭 Philippines, its distribution spans the vast Indo-Pacific region, with confirmed reports from numerous locations including 🇴🇲 Oman, 🇯🇵 Japan, 🇹🇼 Taiwan, 🇹🇭 Thailand, 🇲🇾 Malaysia, 🇮🇩 Indonesia, and 🇦🇺 Australia. Its presence in the 🌊 Red Sea adds a splash of intricate beauty and ecological interest to these vibrant coral ecosystems.
