Thecacera pikachu Pola, Paz-Sedano, Guisado Martín, Warren, Noble & Martín-Hervás, 2026
Description
Species up to 40 mm in length. Mantle smooth, with numerous embedded spicules visible to the naked eye. Spicules star-shaped with blunt ends and small warts. Oral tentacles small and rounded. Rhinophores long, bearing 15–18 lamellae with well-differentiated bases. Rhinophoral sheath slightly smaller than the rhinophore, slightly ovoid, not complete and open inside. Two large retractable semicircular structures with internal branches below rhinophores. Gill at end of first third of body, composed of five tripinnate branchial branches surrounding the anal pore. Highly developed extrabranchial processes on both sides of gill, cylindrical with rounded ends, approximately half the body length.Color pattern
Body pale orange with black spots following a regular pattern along the notum. Two parallel lines of dots along the edge of the notum converging at the tail end, as well as dorsally just above foot. Rhinophoral tips, rhinophoral sheaths, and extrabranchial processes also dotted. Between rhinophores and gills, two larger spots aligned in line.Distribution
Widely distributed in the western Pacific. Type locality is Tasi Tolu Bay, Dili, East Timor. Also recorded from the Philippines, Indonesia, China, Malaysia, and Japan.Etymology
Named after "Pikachu", the popular Pokémon character, due to the resemblance of its yellow-orange body color and black spots to Pikachu's coloration. In Japan, Thecacera cf. darwini is nicknamed "Pikachu", but internationally this species was the one known by the Pikachu nickname.Remarks
A member of the family Polyceridae, subfamily Polycerinae. Found during night dives moving over sandy substrate and coral rubble, feeding on bryozoans and hydrozoans.References
- カンナツノザヤウミウシ（新称）, 鈴木敬宇. (2000). ウミウシガイドブック〈2〉. TBSブリタニカ.
- テカケラ属の一種, 殿塚孝昌. (2003). ウミウシガイドブック〈3〉. TBSブリタニカ.
- Thecacera sp.1, 中野理枝. (2004). 本州のウミウシ. ラトルズ.
- Thecacera sp.13, Helmut Debelius, Rudie H. Kuiter. (2007). Nudibranchs of the World.
- Thecacera sp.1, 中野理枝. (2018). 日本のウミウシ. 文一総合出版.
- Thecacera sp.8, Terrence Gosliner, Ángel Valdés and David Behrens. (2018). Nudibranch and Sea Slug Identification Indo-Pacific 2nd Edition. New World Pubns Inc.
- Thecacera pikachu sp. nov, Pola, M., Paz-Sedano, S., Guisado Martín, P., Warren, L., Noble, K. & Martín-Hervás, M.R. (2026). The most wanted! Gorgeous, delicate and surprising description of three new polycerid species (Mollusca, Heterobranchia) from East Timor. Zootaxa, 5793(1), 193-217.
Featured in this book
Terrence Gosliner, Ángel Valdés and David Behrens. (2018). Nudibranch and Sea Slug Identification Indo-Pacific 2nd Edition. New World Pubns Inc.
New World Publications
This species, Thecacera pikachu, is included in the book.
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Tag:
Same Genus Nudibranchs
Similar Colors Nudibranchs
Academic Database
Sea slug observation data is available in international marine biodiversity databases.