--- title: Girdled Glossodoris (Glossodoris cincta) scientific_name: Glossodoris cincta common_name: Girdled Glossodoris taxon: Nudibranch published: 2026-08-16T17:51:42.037Z updated: 2026-08-16T18:04:49.456Z tags: Girdled Glossodoris, Glossodoris cincta, Nudibranch, Red Sea, Marine Life, Diving url: https://redseacreatures.com/taxon/invertebrate/molluscs/nudibranch/girdled-glossodoris --- # Girdled Glossodoris (*Glossodoris cincta*) ## Quick facts - **Group:** Nudibranch (*Nudibranchia*) - **Size:** up to 6 cm - **Depth:** 3-30 m - **Diet:** Spongivore - **Activity:** Cathemeral - **Rarity:** Uncommon - **Habitat:** Sponge-covered reef, rubble and slopes - **Reproduction:** Simultaneous hermaphrodite, Egg layer - **Hazard:** Poisonous ## How to recognise it - broad frilled mantle skirt carried well out beyond the foot and rippling as it moves - three bands around the margin: a sky-blue outer rim, a dark band inside it, then a broad green band - cream center covered in low granules and a fine rust-red network, with rust-brown patches - dark red-brown rhinophores and gills, speckled with white - up to 6 cm The frilled skirt around this slug is not decoration and it is not swimming gear. It is the weapon, and the bright bands running around it are the label. Chromodorid slugs eat sponges, and sponges are full of defensive chemistry that almost nothing else will touch. This one takes those compounds, moves them through its own body without being harmed, and concentrates them in glands packed along the outer rim of the mantle. In this genus the sorting has been measured: the milder precursor compounds stay back in the digestive gland, while the most potent ones are pushed out to the margin. The slug is not just storing a poison, it is refining it and putting the strongest version exactly where a fish would take the first bite. The banding says so. A predator that has bitten one of these has learned a very specific edge: sky blue at the rim, a dark band inside it, then a broad green one. The pattern is worth more to the slug than any attempt at hiding, which is why it makes no effort to be inconspicuous and crawls over open sponge-covered rock in daylight with the skirt held wide. Everything about the animal is built around that margin. The mantle is far broader than the foot underneath it, so what you see is mostly overhang, and when it is disturbed it flaps the edge in slow waves. Underneath the frill it is a fairly plain animal: a cream to pale green back, low granules, a fine rust-red network, a pair of dark red-brown rhinophores at the front and a rosette of gills at the back, both of which fold away in an instant if anything touches them. Like every nudibranch it is a hermaphrodite, carrying both sets of equipment and mating side by side, right flank to right flank, with each partner passing sperm to the other. The eggs go down in a coiled ribbon stuck to the rock, usually right beside the sponge the adults have been feeding on. One caution on the name. Specialists treat the animals of this ocean as the cincta group rather than as one confirmed species, because the width and shade of those marginal bands vary from place to place and more than one species is probably hiding in there. If it is ever split, the animal on this page may end up under a different name. ## Also known as - **English:** Girdled Glossodoris, Powdered Nudibranch - **French:** Glossodoris à liseré - **Japanese:** チャイロウミウシ, モンジャウミウシ - **Chinese:** 腰帶多彩海牛, 腰帶多彩海蛞蝓 - **Russian:** Глоссодорис опоясанный - **TH:** ทากเปลือยลิ้นแดง ## Scientific synonyms - *Casella cincta* Bergh, 1888 - *Casella foxi* O'Donoghue, 1929 --- *Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/molluscs/nudibranch/girdled-glossodoris)* *Updated: August 16, 2026*