Scientists have found the first animals that can survive and reproduce entirely without oxygen, deep on the floor of the Mediterranean Sea.
The team, led by Roberto Danovaro from Marche Polytechnic University in Ancona, Italy, found three new species from the Loricifera group.
He told BBC World Service they were about a millimetre in size and looked like jellyfish in a protective shell.
One of the three new Loriciferans (so-called because of their protective layer, or lorica) has already been officially named Spinoloricus Cinzia, after the professor’s wife.
The other two, currently designated Rugiloricus and Pliciloricus, have still to be formally described.
They were discovered in the course of three oceanographic expeditions conducted over a decade in order to search for living fauna in the sediment of the Mediterranean’s L’Atalante basin.
The basin, 200km (124 miles) off the western coast of Crete, is about 3.5km (2.2 miles) deep and is almost entirely depleted of oxygen, or anoxic.
Bodies of multicellular animals have been found previously in sediment taken from an anoxic area – or “dead zone” – of the Black Sea, Professor Danovaro told BBC News. But these were believed at the time to be remains of organisms which had sunk there from adjacent oxygenated areas.
What the team found in the L’Atalante dead zone was three species of living animals, two of which contained eggs.
Although it was not possible to extract the animals alive in order to show that they could live without oxygen, the team was able to incubate the eggs in anoxic conditions aboard on the ship.
The eggs hatched successfully in a completely oxygen-free environment.
– from bbc.co.uk