Marionia sp.

Photo courtesy of Shaun Tierney/
Aiduma Island, West Papua, Indonesia
Nikon D200 in a Sea and Sea housing with Sea & Sea YS90 duo strobes on manual settings at half power.
The image was taken with a AF Micro Nikkor 60mm lens set at f32, 1/125 sec
Copyright 2010

Marionia sp. undescribed (who really knows)

These darn (aka - d_mn) tuberculate Marionia's drive me crazy. In the new Reef Creature Indentification Guide (below), the species above is called Marionia rubra. But it doesn't look anything like the original description of M. rubra (see Bill Rudman's Sea Slug Forum ). And, It looks nothing like the critter presented on page 337 of our book, as M. rubra. Even though I must admit, ours doesn't follow the original description either. Do you see why these guys frustrate me?

Knowing how variable these animals are it is hard to even muster an argument one way or the other. If the geographic ranges weren't so separated it would be a slam dunk. Terry, Angel and I show 4 or 5 different animals in Indo-Pacific Nudibranchs and Sea Slugs. M. rubra is described from the Red Sea and has a series of unseparated gill tufts along the margin of the dorsum. These gill tufts are light colored in the description, while ours here are dark red. M. rubra's notal tubercules are larger, denser and outlined in white, unlike our critter here.

My guess is that the animal shown in Paul and Ned's book (page 362 middle left) is the same as ours here. Their photo - middle right - who knows. Certainly, definitely, not M. rubra.

So, without another opinion, I guess my call (as Mike Miller suggests) is that our critter here (and Paul & Ned's) is undescribed. Ho hummmmmm. Another one. Its occurrence in West Papua certainly suggests this.

The long-awaited, 500-page reference detailing 1,600 animals with 2,000 photographs and descriptive text is one of the most comprehensive visual field guides to Indo-Pacific marine invertebrate life.

Over 475 species of opisthobranchs, including dozens of undescribed species. This collection of fine photos adds to our pallet of color variation. A great compliment to "Indo-Pacifc Nudibranchs and Sea Slugs."

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Send Dave email at email address for Dave)

Dave Behrens
Gig Harbor, Washington
Dec., 2010

Beth and Shaun Tierney/

Our diving love affair started after a round-the-world trek when we spent long spells in the tropics, floating over vivid coral reefs and wishing we were down below with the divers. At the time our budget didn't extend to learning to dive but within months of returning to London we signed up for a BSAC course and did our first open water dives in the Maldives.

A few years went by and we became increasingly involved in the diving world as a photo-journalist team with editorial work covering both land and dive travel, marine biology and conservation. A few years later, we took a 'career break' and aimed to dive our way around the world. We didn't manage to see as much as we wanted but it was a great year and led to being published in many international dive magazines, newspapers, travel guides and on the Internet.

Since then, we have become PADI Master Scuba Divers and our work is increasingly focussed on dive travel. We have been lucky enough to return to many of the places we first visited in the 80s and are slowly managing to reach all the other diving destinations we missed in the past.

We have written several dive travel guidebooks and are always working on our website , an information and image-based resource that reviews worldwide diving destinations with first-hand reports, underwater photos and videos. You can visit the site at


We'd like to thank Annabel Thomas of AquaMarine Diving - Bali for helping get this lovely nudi across to Mike Miller for ID. Annabel has been know to spot the odd fabulous nudibranch herself when you can drag her away from the office. As Mike says "Annabel's operation, in my estimation, is the best on Bali." No argument from us on that one.

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

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