Aplysia argus Rüppell & Leuckart, 1830

Description

A medium to large sea hare reaching up to about 200 mm in body length. Ground colour is highly variable, ranging from grey through olive-green and yellowish-brown to dark brown, with conspicuous pale ocellate (eye-like) spots ringed by darker pigment scattered over the dorsum and parapodia. These ocelli are the source of both the scientific and Japanese names. When disturbed, the animal releases a purple defensive secretion from the mantle gland.

Distribution

Widespread across the tropical and subtropical Indo-West Pacific. The type locality is the Red Sea. Records extend from the Red Sea and East Africa through the Indian Ocean to Hawaii, Samoa, Australia and Japan. Indo-Pacific populations were long confused with the Atlantic Aplysia dactylomela, but molecular work has shown them to represent a distinct species, for which Aplysia argus is the oldest available name.

Etymology

The specific epithet argus refers to Argus, the hundred-eyed giant of Greek mythology, alluding to the ocellate spots covering the body.

Remarks

The species is herbivorous on algae, inhabits intertidal to shallow subtidal rocky habitats, and is largely nocturnal, sheltering under rocks by day.

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References

• ジャノメアメフラシ(新称), 滝巌. (1932). 貝類雜記(4). ヴヰナス. 3(4).
• ジャノメアメフラシ, 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.
• ジャノメアメフラシ, 高岡高等学校生物研究会(編). (1964). 富山湾産後鰓類図譜.
• 高岡生物研究会. (2002). 日本海のウミウシ. 第2版.