Your speciemen look like Echiura.

I don't know about pelagic Echiura worms.  

Look this website : http://www.flickriver.com/photos/artour_a/tags/echiura/

Best regards

Thank you Marcel. We caught a few echiurids during the Cruise and they did not look like this at all. They were much smaller, and had an elongated shape. With two distinct sections. This specimen is kidney-shaped, with a smaller kidney-Like part attached to its inferior (?) part. No apparent oral or aboral ends. And we had around 2000 m depth in that particular place.

I'm pleased to drop by and have a closer look to your specimens under the binocular. I can try to dissect it if externally it is difficult to determine. Cheers

Dear Alexandra, before thawing for dissection, we want to at least be sure of the Phyllum to which it belongs, either through advice from colleagues or by molecular methods.

Unfortunately the picture does not help much! and after being frozen not many invertebrates can be dissected... Looks like a mollusk but if you can provide more pictures with different views and a small description, it would help. For instance, size, if there is a head, different dorsal and ventral regions, any kind of skeleton?

I am trying to get hold of any of the other colleagues who were aboard, to see if they keep better pictures. Yes, to me the closest thing could be a nudibranch. But no, it doesn't have a head. There seems to be a hemispherical , kidney-shaped and delicately coloured dorsal (?) side, and a white, flat ventral (?) side where the other, kidney-shaped smaller process is attached. It was large, the hand in the picture gives you a good idea, and it did not seem to have any skeleton or exoskeleton. The delicate coloured skin in the dorsal part was easily damaged when touched. As soon as I get a decent picture I'll hook it up.

Yes, my best guess would be a nudibranch or some opistobranch without a shell...

Hi José Luis

I would recommend to re-attempt amplification of COI (a troublesome task in several taxonomically unrelated organisms) together with a pool of marker genes (16S, 18S, 28S) to increase chances of sorting out at least a phylum code. The picture is definitely too small to get insights. Without dissection, I suggest scraping small fragments of ectoderm (and slide microscopy observations) may help. Finally, did you explore the possibility this might be a body part of a larger organism? good luck and please keep me posted with updates. Best Stefano

Hi, good advice, I will certainly try. No, it does not seem a part or organ of an animal. I am attaching a ventral view with a centimeter scale, where you can appreciate the small, kidney-shaped process. By the way, after several unsuccessful trials during this month I learned that the commenting platform in research gate is absolutely unfriendly for use with smartphones. Cheers, José

Free-living gastropods have orifices:  a mouth, at least, and if their pallial cavity is reduced and they don't have gills (which would be easily observable just by external examination without destructive methods and cutting) then they have  a gential pore and a respiratory pore to the right side of the body. Besides they have cephalic tentacles. As far as I can see, nothing of these traits are recognizable in the animal in the picture. so, it is not a mollusc. Any other molluscs have shells. I can try to identify the animal phyllum without dissecting it just by observing it by my own with the binocular or by taking a small sample of the external body wall. This means just chopping a small piece, what in any case must be done for the molecular study. I'm in the 2nd floor upstairs, and just going down one floor to have a look trhough the binocular doesn't is an inconvenience for me.

By the way, Jose Luis, how do you know which is the ventral part and the dorsal part of the animal?

If you have any other evidences indicating that the body of the figured animal belongs to a bilateral animal, other than the dorsal-ventral side, please, let us know. This may help to identify the phyllum. Is there any evidence of small pits or pores somewhere in the surface of the body distributed randomly or following a precise pattern? Are you sure that this is an individual animal? Could it be a colony?

I agree with Alexandra, and can hardly believe this is a mollusc. You can hardly see any body polarity. My view is probably biased as I am a jellyfish-oriented zoologist, so take my opinion with doubt. Only microscopic/molecular analyses will give reliable insights. Nevertheless, I am intrigued by this discussion so here is my speculation.  Tissue fragments of large jellyfish (umbrellar margin) can be easily rounded up by local regeneration and wounding to assume a ball-like shape. Degenerating tissues (slowly detaching from inner acellular mesoglea) may inflate, assuming similar ball-like pattern.  In the new picture, I see disruption of a previously homogeneous epithelial pigmentation (light - dark brownish colour), VERY similar to the compass jellyfish, Chrysaora hysoscella, which is common along the eastern Atlantic coasts from central Africa to Irish and North seas. After freezing-thawing cycles, you would hardly detected cnidocytes there, but a paraffin section may help to recognise a typical cnidarian ecto-mesogloea-muscle-endoderm layered organisation. Finally, canyons may be both source and sink of gelatinous biomasses (see attached files).

I really cannot tell dorsal from ventral. In fact, I used quotation marks for these words in some of my previous messages. I also pertain to the jelly bunch, but this looked too compact and carbon rich for a normal Jellyfish. but you certainly have a point there.

Something like these published in PloS One?

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0102976

The floating UFO found by José is hardly comparable to the fascinating Dendrogramma spp- animals of few mm in diameter, with distinct oral-aboral and left-right polarity (indeed a bilateral organisation), living on deep sea floor. Unique parallelism: no one can say - so far - where to place them in the animal tree..

Hi Jose Luis! Well, I'm now in Cambridge and lost the chance to meet you  in the Simposia of Marine Biology hold at Gijón. Did anyone there resolved your problem?

Any hind from experts there? I'm wondering if it could be an Urochordate...

It definitely looks that those Dendrogramma published recently...Need any help with molecular analysis?

Dear Acuña, I think I have a fair idea than it can be this animal, but I need more information. Was the animal dead or alive? The first picture has very low quality and can not see anything more than the shape of the animal and your finger, but in the second picture a clear deterioration of the “ventral” epithelial surface is observed. So I suppose that it was floating dead and I deduce that the light bands of the 1st picture are also deteriorated areas. I need to see the “dorsal” surface in more detail, so could you upload a picture of the frozen animal (area above finger). However, I can say with certainty that is not a pelagic or benthic mollusc.

Dear all, apologies. We sequenced the COI gene of this specimen and it turns out to be the pelagic octopus Haliphron atlanticus. Quite a remarkable creature, but not that rare in this part of the world... Thanks everybody for your help. If someone has an interest on tissue samples from this animal, please do not hesitate to ask. Happy Christmas!!!

Well done Josè! Haliphron is giant octopus, so you have Indeed collected a left-over chunk - maybe  resulting from the sloppy feeding of a large predator (maybe a sperm whale)?. Thanks for letting us know, I was still wondering about it. It is double interesting since you collected it from surface waters.. Intriguing story. Best wishes and Happy Christmas from my side, too!

Thanks Stefano! Yes, it could be a bad digestion of a sperm whale, this is a place for them! By the way, thanks to Irene Fernández for letting me slip my octopus among her COI holothurian samples!! Cheers!

Hi all, one further question! I suposse that this serendipitous finding is not worth a publication, but it would be a shame to not having this finding registered in biodiversity databases. Do you think that it is possible to submit a single record like this to sites like OBIS, or similar? Have you ever been in this situation?