Janolus cristatus, also known as the Crystal Tips nudibranch, is a stunning species of sea slug found in the waters around Gozo, Malta. As a member of the family Proctonotidae, this marine gastropod mollusc is a favorite among divers and marine enthusiasts due to its unique appearance and fascinating behavior.
Identifying Janolus cristatus is relatively straightforward thanks to its distinctive features. This nudibranch is semi-transparent with an oval-shaped outline and grows up to approximately 7.5 cm in length. Its body is cream or light brown, and it has short oral tentacles on its head. The lateral cerata, numerous and smooth, have an inflated appearance with bluish-white, iridescent tips. The central digestive gland lobe, visible through each ceras, is thin and brown, dividing into numerous terminal branches at the tips.
The white coloration present on the cerata of Janolus cristatus also appears in patches or lines along the bare central dorsum, around the lamellate rhinophores, and on the metapodium. The rhinophores, joined together at their bases with a swollen and wrinkled accessory caruncle, are somewhat darker than the rest of the body. These unique physical characteristics make Janolus cristatus easy to distinguish from other nudibranch species.
Janolus cristatus is typically found at depths of up to 40 meters, favoring calm, clean waters on hard substrates in the sublittoral zone. This nudibranch prefers environments where it can thrive away from strong currents and disturbed sediments. The spawn of Janolus cristatus appears as a light pink or white string forming a wavy, circular pattern. The eggs are contained within packets separated by transparent patches, giving them a beaded appearance
An interesting fact about Janolus cristatus is its ability to camouflage and blend into its surroundings. The semi-transparent body and the intricate pattern of its cerata help it stay hidden from predators. This nudibranch also has a unique method of deterring predators; when threatened, it can shed parts of its cerata, which continue to move independently, distracting the predator while the nudibranch escapes
Diving in Gozo offers the perfect opportunity to observe the Janolus cristatus in its natural habitat. Reqqa Point, located on Gozo’s north coast, is a prime spot for finding these fascinating creatures. The calm, clean waters and hard substrates provide an ideal environment for the Crystal Tips nudibranch. Divers can enjoy the experience of seeing Janolus cristatus up close, observing its unique characteristics and behavior, making every dive an exciting adventure.
By diving in Gozo, you not only get the chance to explore the beautiful underwater landscapes but also to encounter unique marine life like Janolus cristatus. Whether you are a seasoned diver or a beginner, the opportunity to see these nudibranchs in their natural habitat is an unforgettable experience.
