Halgerda tessellata (Bergh, 1880)
- Location
- Miyakojima, Okinawa, Japan
- Date
- 2018/04/26
- Length
- 20mm
- Depth
- 8.0m
- Water temperature
- 24.0℃
Description
A medium-sized halgerdid reaching about 50 mm in length. The body is semi-firm and gelatinous, with sharp net-like ridges crossing the dorsum that meet at slightly raised, angular intersections. The ridges and the mantle margin are bright yellow, while the depressions between them are brownish with scattered fine white dots that become smaller and denser toward the mantle edge. A dark brown longitudinal stripe runs along the dorsal midline from the head, past the gill pocket, toward the tail. The rhinophores and gills are white with longitudinal dark brown lines, and the rhinophore lamellae are edged with black. As in other members of the genus, the rhinophoral and branchial sheaths are low and smooth, and the dorsum lacks caryophyllidia.Distribution
Type locality: Palau. Halgerda tessellata is now considered a Central and Western Pacific species, recorded from the Philippines, Papua New Guinea, New Caledonia, the Mariana Islands, Japan, and Australia. Records from the Indian Ocean previously assigned to this species were referred to a separate species, Halgerda indotessellata Tibiriçá, Pola & Cervera, 2018.Etymology
The specific epithet tessellata is the Latin adjective meaning "set with small mosaic stones" or "checkered".Remarks
Originally described by Bergh as Dictyodoris tessellata, the species was later transferred to Halgerda. It feeds on sponges. In the molecular phylogeny of a 2023 study, Halgerda tessellata forms a well-supported clade with Halgerda mozambiquensis, Halgerda maaikeae, and Halgerda indotessellata, representing the Pacific lineage of this group.References
- カメセンニンウミウシ（仮称）, 益田一. (1999). 海洋生物ガイドブック. 東海大学出版会.
- テッセラータ, 小野篤司. (1999). ウミウシガイドブック. TBSブリタニカ.
- モザイクウミウシ, 小野篤司. (2004). 沖縄のウミウシ. ラトルズ.
- モザイクウミウシ, 中野理枝. (2004). 本州のウミウシ. ラトルズ.
- Halgerda tessellata, Terrence Gosliner, Ángel Valdés and David Behrens. (2015). Nudibranch and Sea Slug Identification Indo-Pacific. New World Pubns Inc.
- Halgerda tessellata, Donohoo S.A., Villalobos S.G., Hallas J.M. & Gosliner T.M. (2023). Hyperdiversity of the genus Halgerda Bergh, 1880 (Nudibranchia: Discodorididae) with descriptions of fourteen new species. Marine Biodiversity. 53(3): 42. https://doi.org/10.1007/s12526-022-01334-9
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, Halgerda tessellata, 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.