A bizarre new worm with 10 ‘arms’ has been discovered living some 2,500 metres under the surface of the sea, in an isolated ocean basin in the Far East.
Teuthidodrilus samae is a new genus and species of free-swimming annelid worm that appears to be common near the bottom of the Celebes Sea – a deep basin between Indonesia and the Philippines. These ‘squidworms’ can reach a body length of 94mm with their appendages at least as long again and several of them were seen on research dives undertaken in 2007.
“For a worm these guys are quite large,” says Karen Osborn of the University of California, Santa Cruz. “When I first saw them on video I was amazed that something this large and abundant had been missed all this time.”
Osborn suspects the animal feeds on ‘marine snow’ – the name given to organic matter such as dead plankton that drifts down into the depths from the higher, more productive parts of the ocean. One of these creatures was seen attached to a clump of snow, and they are generally too slow swimming to be likely predators.
“We believe they probably are cruising around in the deep water and … are collecting these aggregates of marine snow,” says Osborn, lead author of a new study published in the Royal Society’s Biology Letters journal (doi:10.1098/rsbl.2010.0923). Their stomach contents also seem to back up this hypothesis.
Biodiversity is oceans is huge near the surface and it decreases the further you sink from the sunlight. But once you approach the seafloor it begins to increase again. T. samae inhabits this little studied region of water near the sea floor.
It likely avoided detection for so long due to its ability to swim away from sampling gear. The creature shows the paucity of our knowledge of even common dwellers of the pelagic community, say the authors.
Picture: Royal Society. Their appendages fall off quite easily, possibly why there are only 9 visible in this picture.