Thorunna florens (Baba, 1949)
Description
A small Chromodorididae, body length about 15 mm. The dorsum is smooth. The coloration is complex and beautiful. The area in front of the rhinophores is pink, and this colour extends as a wide longitudinal band on the dorsal midline from between the rhinophores to just in front of the gills. Two narrow lines run from just behind the rhinophores, curving around behind the gills and meeting from left and right; the inner line is opaque white and borders the pink central band, while the outer line is yellow. The outermost mantle edge is white. Inside the mantle margin runs a row of continuous purple markings, separated from the yellow midline narrow line by a thin pale-green band. A yellow transverse band lies just in front of the rhinophores. Rhinophores and gill leaves orange-yellow. A row of purple markings runs along both sides of the tail tip. Radula formula 30×23-25.0.23-25. From the first lateral onward, all lateral teeth are long and spatulate with bifid (rarely trifid) tips — distinct from the 2-3-cuspid laterals of other Hypselodoris species in the same monograph.Distribution
Type locality is Hayama-Samejima, Sagami Bay (intertidal, July 1939, single specimen). The original description (Baba, 1949) records the species only from the type locality.Etymology
The specific epithet florens is Latin for flowering or blooming. The original description does not give an explicit etymology paragraph; the descriptive sense aligns with the Japanese name "Hana-iro-umiushi" (flower-colour sea slug) and reflects the flower-like complex and bright coloration.Remarks
Originally described as Glossodoris florens and later transferred to Thorunna. The radular character — long spatulate laterals with bifid (rarely trifid) tips — clearly separates the species from the 2-3-cuspid laterals of Hypselodoris maritima, Hypselodoris placida, and Hypselodoris sagamiensis described in the same monograph.References
- Glossodoris florens nov. sp., 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.
- ハナイロウミウシ, 小野篤司. (1999). ウミウシガイドブック. TBSブリタニカ.
- 高岡生物研究会. (2002). 日本海のウミウシ. 第2版.
- ハナイロウミウシ, 殿塚孝昌. (2003). ウミウシガイドブック〈3〉. TBSブリタニカ.
- ハナイロウミウシ, 小野篤司. (2004). 沖縄のウミウシ. ラトルズ.
- ハナイロウミウシ, 中野理枝. (2004). 本州のウミウシ. ラトルズ.
- ハナイロウミウシ, 小野篤司 & 加藤昌一. (2009). ウミウシ. 誠文堂新光社.
- Thorunna florens, Johnson R.F. & Gosliner T.M. (2012). Traditional taxonomic groupings mask evolutionary history: a molecular phylogeny and new classification of the chromodorid nudibranchs. PLoS ONE 7(4): e33479.
A Kindle field guide by the site author
Kimoto N. (2026). Sea Slugs of Japan & the Indo-Pacific, 2nd Edition.
Kindle Edition
View on Amazon PR (Amazon Associates)Seasonality
Shooting Locations
Loading shooting locations...
Photos of Thorunna florens
Tag:
Same Genus Nudibranchs
Academic Database
Sea slug observation data is available in international marine biodiversity databases.