Sacoproteus smaragdinus (Baba, 1949)
- Location
- Red Beach, Okinawa Island (East coast), Okinawa, Japan
- Date
- 2017/04/12
- Length
- 10mm
- Depth
- 3.0m
- Water temperature
- 22.0℃
Description
A small sacoglossan, body length about 20 mm. The rhinophores are ear-shaped with a longitudinal groove on the outer side. Oral tentacles are absent. Cerata are not swollen, long fusiform to conical, and easily detached, with branching liver diverticula inside. The pericardium is oval; the anus opens at the anterior end of the pericardium and is half-fused with it. The genital orifice opens just in front of the foremost ceras row, on the right side. The anterior corner of the foot is rounded. The whole body is vivid grass green, with white fine dots scattered on the surface of the cerata. Radular ascending row 4 teeth, descending row about 20 teeth, with straight dorsal edges (no notches) and minute denticles on the ventral edge.Distribution
Type locality is off Hasaki, Sajima Island, Sagami Bay (16 m depth, July 1939, single specimen). The original description records the species only from Sagami Bay.Etymology
The specific epithet smaragdinus is Latin for emerald-green. The original description does not give an explicit etymology paragraph; the descriptive sense reflects the vivid grass-green body colour. The Japanese name "Tama-miru-umiushi" refers to the host alga "tama-miru" (a Codium green alga).Remarks
Originally described as Stiliger (Ercolania) smaragdinus, with Baba himself marking "(?)" to indicate uncertainty in the generic placement. Subsequent molecular work (Krug et al., 2018) erected the genus Sacoproteus, into which this species has been transferred. Feeds on Codium green algae.References
- Sacoproteus smaragdinus (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.
- Stiliger (Ercolania) smaragdinus BABA, 1949. Tamamiru-umiushi., Baba K. (1959). THE FAMILY STILIGERIDAE FROM JAPAN (OPISTHOBRANCHIA-SACOGLOSSA). Publications of the Seto Marine Biological Laboratory. 7(3): 327-334. https://doi.org/10.5134/174635
- タマミルウミウシ, 高岡高等学校生物研究会(編). (1964). 富山湾産後鰓類図譜.
- タマミルウミウシ, 益田一. (1999). 海洋生物ガイドブック. 東海大学出版会.
- タマミルウミウシ, Stiliger (Ercolania) smaragdinus, 益田一. (1999). 海洋生物ガイドブック. 第2刷. 東海大学出版会.
- タマミルウミウシ, 小野篤司. (1999). ウミウシガイドブック. TBSブリタニカ.
- タマミルウミウシ, 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.
- タマミルウミウシ, 小野篤司. (2004). 沖縄のウミウシ. ラトルズ.
- タマミルウミウシ, 中野理枝. (2004). 本州のウミウシ. ラトルズ.
- タマミルウミウシ, 小野篤司 & 加藤昌一. (2009). ウミウシ. 誠文堂新光社.
- Stiliger smaragdinus, Terrence Gosliner, Ángel Valdés and David Behrens. (2015). Nudibranch and Sea Slug Identification Indo-Pacific. New World Pubns Inc.
- Sacoproteus smaragdinus (Baba 1949), Krug P.J., Wong N.L.W.S., Medina M.R., Gosliner T.M. & Valdés Á.A. (2018). Cryptic speciation yields remarkable mimics: A new genus of sea slugs that masquerade as toxic algae (Caulerpa spp.). Zoologica Scripta. 47(6): 699-713. https://doi.org/10.1111/zsc.12310
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, Sacoproteus smaragdinus, is included in the book.
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Same Genus Nudibranchs
Similar Colors Nudibranchs
Academic Database
Sea slug observation data is available in international marine biodiversity databases.