Tambja sagamiana (Baba, 1955)
- Location
- Sunabe Water Treatment Plants, Okinawa Island (Chatan and Southern area), Okinawa, Japan
- Date
- 2012/03/22
- Length
- 50mm
- Depth
- 5.0m
- Water temperature
- 21.0℃
Description
A medium-sized polycerid, body length about 5 cm. The body is deep dark blue, scattered with irregular numerous yellow round spots — a feature that readily distinguishes the species from congeners. Rhinophores deep dark blue. Gill axes green; foot margin also green. Oral tentacles bear a longitudinal groove on the outer side. Three gills, each deeply bifid on both sides. In living specimens the spots are sometimes reported as orange-yellow rimmed with black.Distribution
Type locality is Kasashima, Sagami Bay (a single swimming specimen collected in August 1949). The original description (Baba, 1955) records the species only from Sagami Bay. Subsequent reports have extended the range to other Japanese localities (Kushimoto, Kochi, Okinawa), Taiwan, and southern Korea. The species was also recorded from Maalaea Bay, Maui (Hawaiian Islands) in December 2012 at rocky-reef sites between 3 and 18 m depth, indicating a temperate-to-subtropical West Pacific distribution that extends to the Hawaiian Archipelago.Etymology
The specific epithet sagamiana is a toponymic adjective referring to Sagami Bay. The original description does not provide an explicit etymology paragraph; the geographic derivation is self-evident, and the Japanese common name (Sagami-Ryūgū-umiushi) also reflects the type locality.Remarks
A member of the subfamily Nembrothinae within the Polyceridae, readily recognised by the blue ground colour with yellow spots. Like related Tambja species, it is associated with bryozoan colonies on rocky reefs, on which polycerids in this group typically feed.References
- サガミリュウグウウミウシ（新稱）, 生物學御研究所編. (1955). 相模湾産後鰓類図譜〈補遺〉. 岩波書店.
- Nembrotha sagamiana Baba, 1955, Burn R. (1962). Descriptions of Victorian nudibranchiate Mollusca, with a comprehensive review of the Eolidacea. Memoirs of the National Museum of Victoria, 25: 95-128, text figs. 1-26. https://www.biodiversitylibrary.org/item/120188
- サガミリュウグウウミウシ, 小野篤司. (1999). ウミウシガイドブック. TBSブリタニカ.
- サガミリュウグウウミウシ, 鈴木敬宇. (2000). ウミウシガイドブック〈2〉. TBSブリタニカ.
- サガミリュウグウウミウシ, 小野篤司. (2004). 沖縄のウミウシ. ラトルズ.
- サガミリュウグウウミウシ, 中野理枝. (2004). 本州のウミウシ. ラトルズ.
- サガミリュウグウウミウシ, 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 Tambja sagamiana
Tag:
Same Genus Nudibranchs
Similar Colors Nudibranchs
Academic Database
Sea slug observation data is available in international marine biodiversity databases.