Costasiella kuroshimae M. Ichikawa, 1993
- Location
- Yaene, Hachijo Island, Tokyo, Japan
- Date
- 2018/06/28
- Length
- 3mm
- Depth
- 10.0m
- Water temperature
- 26.0℃
Description
Holotype 4 mm. The anterior part of the head is divided longitudinally by a brown colour pattern, giving the impression of two roundish pouches. The rhinophores are white with black tips; oral tentacles are absent. A brown mark is present medially behind the eyes. The cerata are arranged in seven rows, generally green with white tips, and iridescent dots are scattered over the green parts.Distribution
Type locality: Kuroshima Island (Taketomi, Yaeyama, Okinawa, Japan), on Avrainvillea lacerata var. robustior. Recorded from Japan, the Philippines and Indonesia, in tropical and subtropical waters of the western Pacific.Etymology
The specific epithet kuroshimae is the Latinised genitive of the Japanese island name Kuroshima (the type locality in Okinawa, Japan).Remarks
A sacoglossan ("sap-sucking") sea slug that feeds on the green alga Avrainvillea, sequestering functional chloroplasts and retaining them for photosynthesis (kleptoplasty). The names "Leaf Sheep" and "Sea Sheep" are widely used by English-speaking divers, but the animals usually pictured under these labels are actually the closely related Costasiella sp. 3 rather than this species. Recent molecular work has shown that several additional undescribed cryptic species closely resemble C. kuroshimae externally, and the original description lacks the anatomical detail needed to fix the identity of true C. kuroshimae.References
- Costasiella kuroshimae n. sp., Ichikawa M. (1993). Saccoglossa (Opisthobranchia) from the Ryukyu Islands. Publications of the Seto Marine Biological Laboratory. 36(3): 119-139. https://doi.org/10.5134/176229
- テングモウミウシ（新称）, 小野篤司. (2004). 沖縄のウミウシ. ラトルズ.
- Costasiella kuroshimae Ichikawa, 1993, Jensen K.R., Krug P.J., Dupont A. & Nishina M. (2014). A review of taxonomy and phylogenetic relationships in the genus Costasiella (Heterobranchia: Sacoglossa), with a description of a new species. Journal of Molluscan Studies. 80(5): 511-525.
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 Costasiella kuroshimae
Same Genus Nudibranchs
Similar Colors Nudibranchs
Academic Database
Sea slug observation data is available in international marine biodiversity databases.