First Oxygen-Free Animals Found

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.

Danovaro told BBC World Service they were about a millimetre in size and looked like jellyfish in a protective shell. "We plan to go back and see if there are new surprises for us," he added.

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 (124m) off the western coast of Crete, is about 3.5km (2.2m) deep and is almost entirely depleted of oxygen, or anoxic.