Nembrotha cf. yonowae Goethel & Debelius, 1992

(Figure 24 F)

Material examined. Eleven specimens. MB28-004421, ZWH, 31 May 2010, 16m, 42mm; MB28-004422, ZWH, 0 7 Jun. 2010, ZWH, 18m, 25mm; MB28-0 0 4424, ZWH, 27 May 2010, 18m, 18mm; MB28-0 0 4547, ZRP, 20 May 2012, 2m, 38mm, collected by S. Bruck; MB28-004707, ZRP, 0 6 Aug. 2013, 0.5m, 16mm; MHN-YT1506, ZWH, 0 2 Apr. 2015, 15m, 21mm; MB28-004980, ZWH, 0 3 Apr. 2015, 17m, 16mm; MB28-005003, ZWH, 27 May 2015, 15m, 22mm, collected by M. Andskog; MB28-005004, ZWH, 27 May 2015, 15m, 28mm, collected by M. Andskog; MB28-005020, ZWH; 0 4 Aug. 2015, 17m, 28mm; MB28-005021, ZWH, 0 4 Aug. 2015, 17m, 42mm.

Habitats. Subtropical tidal reefs and rocky reefs.

Occurrences. Zavora.

Geographic distribution. Indo-west Pacific. Japan (Gosliner et al. 2008), Papua New Guinea, Philippines (Pola et al. 2008), South Africa (Gosliner 1987) and Mozambique.

Remarks. Often found feeding on the ascidian Eudistoma caeruleum (Sluiter, 1909), this species is very similar to the description of N. yonowae, although it was only based on external morphology and no type material exists (Goethel & Debelius 1992). Since species of the genus Nembrotha can be highly variable in colour, it is difficult to confirm this identification. Moreover, Pola et al. (2008) note that, so far, there are no clear differences between N. nigerrima, N. cristata and N. yonowae . Therefore additional studies are needed to clarify this potential complex.