Dear English-speaking readers, this page is an automatic Google translation from a post originally written in French. My apologies for the weird sentences and the funny mistakes that could have been generated during the process. If you can read French, the original and correct version can be found here:
This little marine animal is the star of Romblon, in the Philippines. Divers are eager to travel thousands of miles to see this strange sea slug!
A transparent nudibranch
March 2017. I am on the island of Romblon, in the Philippines. "Here we have the Holy Grail of nudibranchs", announces proudly Philipp, of the diving centre The Three P.
The Grail of nudibranchs? Definitely? What's so special about it? "It's a newly discovered nudibranch, very difficult to find and really amazing. But you have to see for yourself. You know, we have divers from all over the world who come here just to photograph it. Its name is Melibe colemani. Tell the guide you want to see it, he'll show you some..."
And it's true, you have to see it to believe it... This sea slug is translucent! You can see its organs through the body! 😮
It's not the only weirdness. Its body is made up of a network of tubes, of a whitish beige colour, which are in fact digestive glands. On his back, they extend into imposing growths, called cerata.
I admit I didn't know any of this until I saw my first Melibe colemani... 😍 In fact, even when I have it in front of me, the first time I don't see anything!
Very difficult to spot
Joseph alias "Erap", my Filipino guide, nevertheless insists on showing me something, pointing two fingers at his eyes and then his index finger at a tuft of soft coral. Seeing that I can't see anything, he makes a circle with the tip of his pointer over the polyps, where I'm supposed to look, and then gently spreads the "stems" that are wavering in the current. But I still can't see anything. No, nothing at all. Besides, I don't even know what the thing I should see looks like.
And then, finally, that's it!!! I SEE it!
I still need a little more time to locate the front and back of the beast, which should be about 4-5 centimeters long. Moreover, this nudibranch is always on the move. With each wave movement, it undulates too, moves forward, straightens up, raises its head... Is that its head, there? Wooooow... I can't believe it.
His mouth is like a reticle, a mini-net that is capable of capturing tiny and invisible prey, I guess, that it only has to digest. It's a gelatinous monster. A multiform slug. A ghost nudibranch.
In addition, there is not only one ... Joseph draws my attention to his translucent little friends. Underwater, there are nudibranch corners, as there are mushroom corners in the forest! 😂
Without the eye of my guide and his knowledge of the site (I mentioned in a previous article on muck-dive), I would never have managed to observe and photograph this wonder of nature ... Melibe colemani is so light, so vaporous, that it must be approached with infinite precautions. Because a simple movement of the hand over the little beast is enough to create a current able to lift it from the substrate and float it in full water. It does not look like anything anymore, then. It would be easily confused with a vague spongy debris washed away by the current.
During this dive - and a few others the following days, where I will ask again to see the Melibe colemani - So I spend a very long time stuck on the spot, to observe and photograph the tiny and fascinating animal. A game of patience ...
Melibe colemani, a recent discovery
The Melibe colemani is a nudibranch filterer who was named after the man who discovered him, the Australian naturalist and photographer Neville Coleman (1938-2012). A find made at Mabul, the neighboring island of Sipadan, in Malaysia, near Borneo: Coleman published the first image in 2008, in its Nudibranchs Encyclopedia.
I really like his account of the dive in which he first saw and photographed this curious little creature, hitherto unknown to scientists. He also took time to really see what he had in front of him ... The story is reported here on this American site of enthusiasts:
The nomenclature and scientific description of the species were only established in 2012 (one month after Coleman's death) by two marine biologists specializing in nudibranchs, the Spanish Marta Pola and the American Terrence Gosliner. For science buffs, here are two links (in English) to their study:
(Coincidentally, I discovered on The Three P dive center's Facebook page that Terrence Gosliner also spent a week in Romblon recently, in April 2017, for his scientific research!)
In addition to Mabul in Malaysia, Melibe colemani has also been observed in Indonesia Komodo and Lembeh. In the Philippines, Romblon, divers at The Three P Center spotted it for the first time in 2013.
The species is probably widespread in the waters of the Coral Triangle. But this nudibranch is so hard to see, that it is not surprising that it was discovered only recently. Especially coveted by the divers photographers macro, it is considered a rarity. The advantage in Romblon is that the guides know where to find them.
In any case, for me, under water, it's ecstasy. The Melibe colemani does not look like any nudibranch I've encountered so far. It's new, strange. What an extraordinary creature! The Graal. I had been told ...