Tropical Indo-West Pacific.
UPPER RIGHT: on Porites coral colony, 6-7mm long, Touaourou, S of Yaté, New Caledonia, October 1988.
LOWER LEFT: same locality, animal with egg mass.
LOWER RIGHT: 2 animals, 5-7mm long, with "clutch" of egg masses laid under Porites colony, Africana Bch, 1km south of Kunduchi Bch, Dar es Salaam, Tanzania. PHOTOS: Bill Rudman.
Phestilla minor has previously been reported from East Africa, Hawaii and the Great Barrier Reef, giving it a wide Indo-West Pacific distribution. This small species, seldom more than 7mm long, is always found associated with colonies of the coral Porites, on which it feeds. Its eggs are usually laid alongside the coral colonies. There is one colour form with very little epidermal pigmentation which well matches the colour of the coral colony, and another form which is heavily pigmented opaque white, which matches the shape and colour of small abrasions, probably fish feeding scars, which are found scattered over Porites colonies.
Studies I did in Tanzania showed that P. minor grows rapidly (2 to 9mm in ten days) and starts egg-laying at between 6-9mm. Animals tend to form pairs, (as in P. lugubris), and produce about 10 egg masses, each mass having about 120 eggs. Lecithotrophic (non-feeding) veligers hatch after about seven days and remain in the plankton for a very short time(3-4 days).
• Rudman, W.B. (1981) Further studies on the anatomy and ecology of opisthobranch molluscs feeding on the scleractinian coral Porites. Zoological Journal of the Linnean Society, 71: 373-412.
LOWER LEFT: on Porites coral colony, 6-7mm long, Touaourou, S of Yaté, New Caledonia, October 1988., animal with egg mass. LOWER RIGHT: 2 animals, 5-7mm long, with "clutch" of egg masses laid under Porites colony, Africana Bch, 1km S. Kunduchi Bch, Dar es Salaam, Tanzania. PHOTOS: Bill Rudman.
Rudman, W.B., 1999 (May 23) Phestilla minor Rudman, 1981. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/phesmino