The Armina sp. sticking out of the sand.
The whole photo, showing the nudibranch close to what is probably its diet, a sea pen. Photos Pierre Niehaus.
Dermatobranchus sp.1, showing family characteristics. Photo Andrew Taylor.
Pierre found this odd looking thing on the way back from JJM, or Photographers Reef as it is also known as. He showed SURG the photo, and had us thoroughly baffled, as it didn't look like anything we had seen before. It was only by looking through a nudibranch guide searching for another species that we found out what it is. It is a nudibranch, member of the Arminacea, specifically, of the family Arminidae. A number of the same family are known to occur, including Dermatobranchus sp.1, which shows family characteristics of ridges along the back, and the two rhinophores set closely together at the front of the animal. Some members of the family burrow in the sand, something this species seems to be doing as well, having just emerged. They are also known to feed on sea pens, which is the red thing shown in the middle photograph (which is Actinoptilum molle.) We asked Dr. Gosliner for help, and he said that the nudibranch shown is clearly distinct from the only other Armina described in his book, A. gilchristi. It is quite possible that this thus represents a new, undescribed species!
Thanks to Dr. Gosliner for information.
Nudibranchs of Southern Africa - a guide to the opisthobranch molluscs of southern Africa, T Gosliner, 1987.
Nudibranchs and Sea Snails, Indo-Pacific field guide. H Debelius, 1996.