Phestilla melanobrachia Bergh, 1874

Yonow, Nathalie, Anderson, R. Charles & Buttress, Susan G., 2002, Opisthobranch molluscs from the Chagos Archipelago, Central Indian Ocean, Journal of Natural History 36 (7), pp. 831-882 : 875

Phestilla melanobrachia Bergh, 1874

Phestilla melanobrachi a Bergh, 1874: 1, taf. II, ®gures 1±14; Yonow, 1994a: 126, ®gure 17A; Yonow, 2000: 122, pl. 38.

Material. Chag96/88: 25 mm; cave on inner reef, Nelson Island, Great Chagos Bank; 3 March 1996; at 23 m depth.

Description. Ground colour deep orange-red. Rhinophores simple, long and tapering, deep orange-red. Digitiform cerata orange, with orange-red tips.

Geographic distribution. Indo-West Paci®c: South Africa and Red Sea to Hawaii (Yonow, 1994a, 2000).

Remarks. This species is normally found associated with dendrophyllid corals. The single specimen was found on the ¯oor of a cave; it is possible that it was dislodged from corals on the cave roof by exhaust bubbles. Members of the genus tend to be medium-sized aeolids and have evolved to feed on corals. As a result, they lack the cnidosacs in the cerata, which have been replaced by enlarged gland cells. Three species are known: P. melanobrachia and P. minor Rudman are Indo- West Paci®c in their distributions and P. lugubris (Bergh) (as P. sibogae Bergh auctt.) occurs throughout the Indo-Paci ®c.