Dermatobranchus sp.(undescribed)

Image courtesy of Yanitza Grantcharska
Crystal Bay - Nusa Penida, Indonesia

Wow - another new one. Wished we had had this one when we prepared the second edition of NSSI. Darn - I guess we'll just have to wait for the third edition.

This is an exciting find as it is another flatworm mimic/model. It looks just like the polyclad flatworm, Pseudoceros scriptus (page 77 of Marine Flatworms by Newman & Cannon). The reason I say mimic/model is because, at this time, we don't know who is the mimic, the flatworm or the nudibranch, and which is the model being mimicked. This will take some study.

Several examples of sea slug/flatworm mimicry are presented in Nudibranch Behavior (pages 155-157). These include mimics of Goniobranchus (as Chromodoris) geometricus, G. preciosa, Chromodoris magnifica, Chelidonura varians and Felimare (as Hypselodoris ghiselini). Mimicry is a complicated and interesting biological phenomenon; neither the model nor the mimic can see each other or even know that the other exists. An outcome of many years of natural selection, it is however thought to be a form of protection for the mimic, as predators avoid it because it resembles a foul tasting (usually acid secreting) model, the predator remembers from an unfortunate experience in the past.

Yanitza's new find here is placed in Dermatobrachus because it lacks secondary respiratory leaves on the sides of the body, and the anterior edge of the mantle is incomplete, fused with the head behind the rhinophores. The color of the rhinophores differs from that of the Pseudoceros, but I doubt any predator would notice that. Otherwise the white dorsum with orange marginal band, and mid-lateral black marks, make it a ringer.

Great find Yanitza.


Newman, L. & L Cannon. 2003. Marine Flatworms - The World of Polyclads. CSIRO Publishing, Australia. 97 pages.

Dave Behrens
Sammamish, WA 98074
Nov., 2018
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WEBMASTER'S NOTES: Ocean lover since birth, Yanitza got addicted to the marine conservation world thanks to Chad Scott at the New Heaven Reef Conservation Program in Thailand, in 2013. Her nudibranch mentor and beloved friend, Rahul Mehrotra introduced her to the nudi realm, and since then she can't avoid having her head into the reef or muck looking for tiny creatures.

Today, Yanitza is the founder and executive director of Save The Plastic, an international organization that fights marine plastic pollution, and she spends all her free time underwater, scuba diving and staring at all the macro world.

The Webmaster would also like to thank Gary Cobb from down under for making this BOW possible!

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Attention all you Sluggers, and you know who you are!

The NSSI 2nd edition is now available in ebook PDF and book form . The hard back version will become available Nov. 1st. Both will cost $65 (individually).

You will need to jump through a few hoops to get the electronic version as pdf distribution is protected by Adobe ID!! Please read the following to enable reading your electronic purchase!

This new 2nd Edition is updated and reorganized, including 185 new species. Among other features, the new edition includes additional photographs of species, an identification key, and an up-to-date classification reflecting the latest evolutionary relationships. The Indo-Pacific represents the largest expanse of tropical ocean in the world, stretching from the Indian Ocean coast of southern Africa and the Red Sea to the central Pacific of the Hawaiian Islands, Easter Island and the Marquesas.

This region supports the most diverse marine fauna of any place in the world for most groups of marine organisms. The nudibranchs and sea slugs are no exception to this rule; there are about 3,000 described species of these organisms in the world and at least 40% of these have been found exclusively in the Indo-Pacific tropics. This book illustrates 2,138 Indo-Pacific nudibranchs and sea slugs, including many undescribed species.

4 From left to right, Terry Gosliner, Angel Valdes, Dave Behrens La Jolla, Calif.

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