Goniobranchus alius (Rudman, 1987)

(Figure 5 K–L)

Material examined. Ten specimens. MHN-YT10, ZRP, 17 Jun. 2011, 1m, 14mm; MB28-004539, ZRP, 0 6 May 2012, 2m, 14mm, collected by S. Bruck; MB28-004540, ZRP, 0 6 May 2012, 2m, 9mm, collected by S. Bruck; ZMBN117024, ZRP, 0 6 May 2012, 2m, 8mm; ZMBN117058, ZRP, 16 Apr. 2014, 0.5m, 16mm; ZMBN11 7063, POD, 11 May 2014, 15m, 16mm; MB28-004864, 2 spcs., POB, 16m, 6-8mm; MB28-0 0 4983, ZSC, 25 Apr. 2015, 20m, 15mm; MB28-005018, ZRP, 0 4 Aug. 2015, 1m, 16mm.

Habitats. Subtropical tidal reefs and rocky reefs.

Occurrences. Ponta do Ouro and Zavora.

Geographic distribution. Indian Ocean. Sri Lanka (Yonow 1984), Tanzania, Réunion Island (Rudman 1987), Madagascar, South Africa (Gosliner et al. 2008) and Mozambique.

Remarks. Specimens show colour variation ranging from a white dorsum with purple mantle edge to a brownish dorsum with light yellow spots inside the purple margin. The latter pattern resembles Goniobranchus aureopurpurus from the West Pacific. Rudman (2005b) suggests that “ G. alius, G. aureopurpureus, G. rufomaculatus and G. albopustulosus ” may be the same species with wide geographic distribution and colour variations.