Aplysia oculifera A. Adams & Reeve, 1850

Location: Wannai, Osezaki, Shizuoka, Japan
Date: 2019/06/12
Length: 22mm
Depth: 1.0m
Water temperature: 19.0℃

Description

A medium-sized sea hare of the family Aplysiidae, reaching about 60-80 mm in length. The ground colour is variable, ranging from green through olive to brownish, and the body is sprinkled with small whitish and yellowish dots. A number of these dots are encircled by dark rings, giving the appearance of small eye-spots (ocelli), the character that gave the species its name. The body is moderately elongate with an acutely pointed posterior end, and the parapodia are well developed and can be undulated for short swimming bursts. The posterior tentacles are subulate and sharply pointed. When disturbed, the animal releases a purple ink from the mantle cavity.

Distribution

Widely distributed throughout the Indo-West Pacific, recorded from the Red Sea and East African coast, Madagascar, Mauritius (type locality), South Africa, India, Singapore, the Philippines, Korea, Japan, Palau, the Midway Islands and the Hawaiian Islands. In Japan it occurs on rocky shores and shallow reefs from central Honshu southwards.

Etymology

The specific epithet oculifera is from Latin oculus ("eye") + -fer ("bearing"), referring to the eye-like dark-ringed spots scattered over the body. The original description explicitly highlights these "beautiful eye-like spots" as the most striking character of the species.

Remarks

A herbivorous grazer reported to feed on green algae such as Ulva spp. on intertidal and shallow subtidal rocky shores. Because of the wide colour variation, identification in the field relies on the combination of the eye-like ocelli, the dotted pattern, and the shape of the parapodia and posterior tentacles, rather than on ground colour alone.