Overview
Poindimie’s Aeolid Nudibranch (Phyllodesmium poindimiei) is one of the most mesmerizing and biologically sophisticated marine mollusks gracing the coral reefs of the tropical Indo-West Pacific. First described scientifically from specimens discovered off Poindimié on the northeast coast of New Caledonia, this magnificent sea slug resembles a living, pulsating bouquet of glowing pink and turquoise coral tentacles. Beyond its breathtaking aquatic aesthetic, it is renowned for engaging in endosymbiosis: it sequesters viable photosynthetic algae from its soft coral prey, essentially functioning as a solar-powered animal.
Biology and Physical Characteristics
Phyllodesmium poindimiei features an elongated, translucent white or pale pink body covered dorsally with dozens of elongated, finger-like cerata. These cerata are flushed with rich salmon-pink to iridescent magenta hues and terminate in striking electric-blue or turquoise rings. Unlike typical aeolid nudibranchs that store stinging nematocysts (cleptocnidae) for defense, Phyllodesmium species house living dinoflagellates (zooxanthellae) harvested from octocorals within complex branches of their digestive gland. These hosted algae conduct photosynthesis within the cerata, supplying the sea slug with direct glucose and metabolic nutrition.
Behavior and Ecology
This diurnal marine slug glides gracefully across living coral surfaces using a muscular ciliated foot lubricated with clear mucus. It feeds primarily on soft octocorals of the genus Carijoa and Stereonephthya, using its chitinous radula to slice through polyp tissues. To defend against predatory reef fishes without the aid of stinging cells, the nudibranch readily practices autotomy: if grasped by a predator, it detaches one or more of its vibrant cerata. The discarded cerata wriggle frantically and emit bioluminescent-like flashes in the water column, distracting the predator while the slug glides to safety.
Conservation and Human Impact
While Phyllodesmium poindimiei enjoys a broad geographical distribution across the Coral Triangle and adjacent Pacific waters, its long-term welfare is intimately linked to the health of global coral reef ecosystems. Anthropogenic climate change, rising sea temperatures, and ocean acidification induce mass coral bleaching events that devastate the soft coral host colonies upon which these nudibranchs rely for food and symbionts. Marine protected areas throughout the Great Barrier Reef and Raja Ampat serve as essential sanctuaries for reef biodiversity.
Interesting Factoid
This stunning sea slug is solar-powered: it eats coral, steals the coral’s microscopic photosynthetic plant cells, and houses them in glowing pink and blue tentacles, basking in shallow reef sunlight to produce its own food!
Last updated: October 2026