Elysia lobata
Gould, 1852

Order: SACOGLOSSA
Superfamily: ELYSIOIDEA
Family: Elysiidae

DISTRIBUTION

Known from Hawaii, Marshall Ids, Japan (Okinawa, Kerama Ids)

PHOTO

Zamami, Kerama Ids, 10m, off Okinawa, July 13-21,
Length: 10mm. Photo: Jun Imamoto

Reported to be common in Hawaii, where it was originally described in a brief account by Gould: "Animal slug-like, greenish, dotted with black, and bordered with yellow; edge of mantle expanded in to a three lobed lateral wing. Head small with very large and long tentacles, tipped with sky-blue; ...."

The three-lobed parapodia are clearly visible in Gould's illustration. A much fuller description and clearer illustration was published by Ostergaard (1955) where he described it as a new species, E. elsieae, noting the resmblance to E. lobata but suggesting Gould's description was inadequate. Kay (1969) identifies this species with Gould's name and this has apprently been accepted by workers fanmilar with the Hawaiian fauna.

The main characters would appear to be the trilobed parapodia, the lobes gradually diminshing in size from the front ot the back. The rhinophores have a brownish-pink band midway along their length and a bluish tip. The background colour of the body and parapodia ranges from translucent clear to greenish, probably dependent on the stage of the feeding cycle and the parapodia have scattered black and white spots. At the parapodial edge there is a broad translucent pinkish marginal band which has regularly spaced deeper pink patches. At the inside edge of this band is a narrow band of milky yellow, and below this there can be a band of dark green specks. Can grow to 15mm long.

References:
• Gould,AA (1852): Mollusca & Shells. United States Exploring Expedition during the Years 1838-1842. 12: 1-510. [with Atlas of Plates, 1856]
• Kay, E.A. 1979. Hawaiian Marine Shells, Reef and Shore Fauna of Hawaii, 4: Mollusca. Bernice P. Bishop Museum Special Publication 64(4), xviii + 653 pp.
• Suzuki, K. 2000. Opisthobranchs of Izu Peninsula. TBS-BRITANNICA & Co., Ltd., Japan. 178pp.
• Ostergaard, J.M. (1955) Some opisthobranchiate Mollusca from Hawaii. Pacific Science, 9(2): 110-136. (Pls. 1-2)

Authorship details
Rudman, W.B., 2001 (September 2) Elysia lobata Gould, 1852. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/elysloba

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