Phyllodesmium horridus, the coral nudibranch.
Flabellina funeka, the purple lady nudibranch.
Tritonia nilsodhneri, the whip-fan nudibranch.
Eunicella tricoronata, sinuous seafan.
Eunicella papillosa, nippled seafan.
Ancula sp.
All photos Guido Zsilavecz
Good conditions at Castle Rocks over the weekend allowed of SURG members and contributors to look intensely for nudibranchs, with fantastic results. A total of 18 species were seen and photographed, including a few unusual ones.
Phyllodesmium horridus, the coral nudibranch.. Although Gosliner includes Castle Rocks as part of the distribution of this species, SURG members had yet to find it there. Andrew Taylor did find it at nearby Pyramid Rock, and now, on a small vertical reef section, well protected from the prevailing swell and surge, we found many. Most of them were rather small and nowhere near as large as those found at Percy's on the other side of the bay.
Flabellina funeka, the purple lady nudibranch.. The original description of this species lists Castle Rocks as a site where it was found, but does not state where at Castle - only a depth of 10 m is given. We have reports of it being seen at reefs further offshore from Miller's Point and Castle, but this is the first record we know of it occuring inshore at Castle as well, in about 6 m of water.
Flabellina funeka is a often a distinctly "messy"-looking nudibranch, with its cerata all over the place. This is because instead of each of the cerata being an "individual", that is, attached to the main body by itself, the cerata are instead branched, with several attached to a peduncle, ranging from 4 to 6, up to 9 to 10 cerata per peduncle. The purple colour of the body is very distinct, and sets it apart from Cratena capensis, which also has white-tipped red cerata. There is a white morph of F. funeka, which looks even more similar. To differentiate them one must either see the branched cerata, or the tips of them, which directly from above look like they are indented.
Tritonia nilsodhneri, the whip-fan nudibranch. Gosliner notes that he has only found this species along the Atlantic coast, its presence at various Rooi Els sites, and sites offshore from Miller's Point, indicates that the range has either extended or Gosliner simply did not find it elsewhere. Looking for them we found it to be common at Castle Rocks as well. In contrast to those found at Rooi Els, we did not find it on the sinuous sea fan, Eunicella tricoronata, but instead on the much smaller nippled sea fan, Eunicella papillosa. As the later is paler in colour, so were the nudibranchs and their egg cases. Gosliner notes that the species preys on sea fans of the genus Eunicella, so the nudibranchs were not out of place. As we saw few sinuous sea fans on the dive, we could not investigate whether this preference for the nippled sea fan was only a local one.
Ancula sp., (no common name yet - any ideas? Suggestions welcome!) It was seeing this species at Percy's which prompted us to look for it at Castle, now that we know what environment it liked (which seems to be red sponges which thinly cover some walls, although Gosliner mentions bryozoans.) We managed to find one.
Following is a complete list of species found this weekend by various divers:
- Amanda armata (City-lights nudibranch)
- Ancula sp.
- Aplysia parvula (Dwarf seahare)
- Bonisa nakaza (Gas-flame nudibranch)
- Cadlina sp.1 (Saddled nudibranch)
- Ceratosoma ingozi (Inkspot nudibranch)
- Cratena capensis (Orange-eye nudibranch)
- Flabellina capensis (White-edged nudibranch)
- Flabellina funeka (Purple lady nudibranch)
- Hypselodoris capensis (Cape dorid)
- Janolus capensis (Silvertip nudibranch)
- Lecithophorus capensis (Ghost nudibranch)
- Limacia clavigera (Orange-clubbed nudibranch)
- Okenia amoenula (Fiery nudibranch)
- Phyllodesmium horridus (Coral nudibranch)
- Polycera capensis (Crowned nudibranch)
- Tambja capensis (Black nudibranch)
- Tritonia nilsodhneri (Whip-fan nudibranch)
- Aeolidiella indica (Indian nudibranch)
- Chromodoris heatherae (Red-spotted nudibranch)
- Elysia sp. (Plant-sucking nudibranch)
- Notobryon wardi (Irridescent nudibranch)
- Philine aperta (Sand slug)
- Placida dendritica
- Pleurobranchaea bubala (Warty pleurobranch)
Nudibranchs of Southern Africa - a guide to the opisthobranch molluscs of southern Africa, T Gosliner, 1987.
Description and revision of some South African Aeolidacean Nudibranchia (Mollusca, Gastropoda), T Gosliner and R Griffiths. Annals of the South African Museum, Volume 84, Part 2, July 1981.
Two Oceans, a guide to the marine life of Southern Africa, GM Branch, CL Griffiths, ML Branch and LE Beckley, 1994.