Phyllidia ocellata

A 2.5 inch long specimen on its prey sponge (photo by David Lehrian).

 Animal found on White Wall, Rainbow Reef, Taveuni, Fiji, about 70 feet deep, 17 April 2024.

Phyllidia ocellata Cuvier, 1804

            Yellow to golden-yellow body, with dorsal tubercles the same coloration. Four to ten black circles occur irregularly over the dorsum, often with a white ring on their circumference. These circles usually surround one of the yellow dorsal tubercles.

            The living animals reach 70 mm in length. They occur on shallow reefs, from 1-20 m deep, conspicuously out in the open.

            This species is widespread in the Indo-Pacific. Mike Miller (pers. comm. 12 May 2024) wrote me that “Phyllidia ocellata is certainly one the most commonly encountered sea slugs in my travels throughout the Philippine and Indonesian waters of the Indo-Pacific."

            As currently accepted, P. ocellata has an incredibly wide range of color variation, illustrated in Gosliner et al., 2018: 213. When this species was first presented as a Nudibranch of the Week back in 1999, the opening photograph by Helmut Debelius actually showed one of the extreme color variations. However, in that BOW, the link to Mary Jane Adams’ photo shows an original-Cuvier form. She noted, “I spotted this outrageously patterned nudibranch from thirty feet away as I swam up to a patch of reef off the coast of southeastern Papua New Guinea. It was sitting in the open on the edge of the reef in ten meters of water.”

            Brunckhorst (1993: 35-37) found no anatomical variation among some of the forms. However, it should be noted that recent DNA studies have found formerly single species to be one or more species, with very subtle but consistent differences. This may be another instance of “cryptic species,” although not so cryptic externally.

            The color variation illustrated here is an exact match for the original illustration and description by Cuvier.

Literature Cited

Brunckhorst, David J. 1993. The Systematics and Phylogeny of Phyllidiid Nudibranchs (Doridoidea). Records of the Australian Museum (1993) Supplement 16: 107 pp.

Cuvier, Georges. 1804. Mémoire sur la Phyllidie et sur le Plleuro-branche, deux nouveaux genres de mollusques de l’order des gastéropodes, et voisins des patelles et des oscabrions, don’t l’un est nu et don’t l’autre porte une coquille cachée. Annales du Muséum d’histoire naturelle 5: 266-276.

Gosliner, Terrence M., Ángel Valdés & David W. Behrens. 2018. Nudibranch and Sea Slug Identification, Indo-Pacific. New 2nd edition. New World Publications, Inc., Jacksonville, Florida. 451 pp.

Dr. Hans Bertsch
Imperial Beach, Calif
Jun., 2024
Send Hans email at
I would like to thank Jan Kocian for the use of his marvelous image of P. ocellata.

Hans with granddaughter Adriana Ivette Cadena and her cat Akane. June 2023, Imperial Beach

David Lehrian lives in Monterey, California, and started diving in 2018. Living in one of the better places in the United States for diving he has amassed over 500 dives in his short dive career. He started doing underwater photography almost immediately after being certified. He has dove quite a bit in Mexico, both in the Caribbean and the Sea of Cortez as well as his favorite dive destination, the Revillagigedo Archipelago a.k.a. Socorro Islands. He recently took a trip to the island of Taveuni, Fiji where he photographed these Phyllidia ocellata animals. He enjoys shooting both wide angle and macro photography, and he records all his dives through photography and publishes them to

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