Elysia pusilla (Bergh, 1872)
- Location
- Tengan(Kombu), Okinawa Island (East coast), Okinawa, Japan
- Date
- 2015/06/11
- Length
- 10mm
- Depth
- 5.0m
- Water temperature
- 25.0℃
Description
A small sacoglossan. In life the animal is only about 2 mm long. According to the type figure the colour is uniformly leek-green, more strongly so on the head and the outer face of the parapodial flaps owing to innumerable fine dark green dots. The tentacle tips are white, and a single (rarely double) row of whitish spots runs along the body margin. The body is rounded anteriorly and tapers posteriorly. The head bears two short, thick tentacular rudiments with black eyes showing through at their base. The parapodial flaps are strongly developed.Distribution
Type locality: Aibukit, Palau (Pelew) Islands, western Pacific. The species is now known to range widely across the tropical Indo-West and Central Pacific.Etymology
The specific epithet pusilla is Latin for "very small, tiny", referring to the diminutive size of the species — in life only about 2 mm.Remarks
Originally placed as the type species of the new genus Elysiella, later reduced to a junior synonym of Elysia, establishing the current combination. The species is a strict Halimeda specialist and shows poecilogony (different developmental modes in geographically distinct populations).References
- Elysia halimedae n. sp., Macnae W. (1954). On Four Sacoglossan Molluscs new to South Africa. Annals of the Natal Museum 13(1): 51-64.
- Elysia (Elysia) halimedae MACNAE, 1954 Uchiwa-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
- Elysia pusilla (Bergh, 1872), Vendetti J.E., Trowbridge C.D. & Krug P.J. (2012). Poecilogony and population genetic structure in Elysia pusilla (Heterobranchia: Sacoglossa), and reproductive data for five sacoglossans that express dimorphisms in larval development. Integrative and Comparative Biology. 52(1): 138-150.
A Kindle field guide by the site author
Kimoto N. (2026). Sea Slugs of Japan & the Indo-Pacific, 2nd Edition.
Kindle Edition
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Photos of Elysia pusilla
Same Genus Nudibranchs
Similar Colors Nudibranchs
Academic Database
Sea slug observation data is available in international marine biodiversity databases.