Elysia trisinuata Baba, 1949
- Location
- Tengan(Kombu), Okinawa Island (East coast), Okinawa, Japan
- Date
- 2015/06/11
- Length
- 15mm
- Depth
- 4.0m
- Water temperature
- 25.0℃
Description
A small to medium-sized Elysia, body length 5-30 mm. Diagnostic features: (i) numerous conical small papillae on the outer surface of the rhinophores and parapodia; (ii) three indentations on each parapodial margin (anterior, middle, posterior) — when the parapodia are folded close to the dorsum at rest, three small round openings are formed between them. The parapodia are narrow. The anterior corner of the foot is rounded. Body colour grass green; the cephalic region and outer faces of the parapodia bear scattered vermilion fine dots. Radular ascending row 5-8 teeth, descending row 9 teeth, with a row of microdenticles on the ventral edge of each tooth.Distribution
Type locality is off Nishi-no-saki, Sagami Bay (500 m offshore, 10-12 m depth, August 1940 and January & April 1941, 9 specimens, on Codium algae). Also recorded from off Kurosaki (15 m), Kasago-ne off Sajima (13 m), and Hayama-Owashima (14-17 m, on Codium) within Sagami Bay.Etymology
The specific epithet trisinuata is a Latin compound of tri- (three) and sinuata (sinuated), referring to the three indentations on each parapodial margin. The original description does not give an explicit etymology paragraph; the descriptive sense is self-evident.Remarks
Feeds on Codium algae, with observations on both Codium "saki-buto-miru" and "hira-miru". The Japanese name "Hira-miru-midori-gai" refers to the host alga.References
- Elysia trisinuata Baba, 1949, Baba K. (1949). Opisthobranchia of Sagami Bay collected by His Majesty the Emperor of Japan (相模湾産後鰓類図譜). Iwanami Shoten, Tokyo. 4+2+194+7 pp., pls. 1-50.
- Elysia (Elysia) trisinuata BABA, 1949 Hiramiru-midorigai, Baba K. (1957). THE SPECIES OF THE GENUS ELYSIA FROM JAPAN. Publications of the Seto Marine Biological Laboratory. 6(1): 69-74. https://doi.org/10.5134/174573
- ヒラミルミドリガイ, 鈴木敬宇. (2000). ウミウシガイドブック〈2〉. TBSブリタニカ.
- 高岡生物研究会. (2002). 日本海のウミウシ. 第2版.
- ヒラミルミドリガイ, 中野理枝. (2004). 本州のウミウシ. ラトルズ.
- Elysia trisinuata, Trowbridge C.D., Hirano Y.J. & Hirano Y.M. (2008). Sacoglossan opisthobranchs associated with the green macroalgae Codium spp. on Pacific rocky shores of Japan. Venus. 66(3-4): 175-190.
- ヒラミルミドリガイ, 小野篤司 & 加藤昌一. (2009). ウミウシ. 誠文堂新光社.
A Kindle field guide by the site author
Kimoto N. (2026). Sea Slugs of Japan & the Indo-Pacific, 2nd Edition.
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Photos of Elysia trisinuata
Tag:
Same Genus Nudibranchs
Similar Colors Nudibranchs
Academic Database
Sea slug observation data is available in international marine biodiversity databases.