The International Census of Marine Life has catalogued more than 17,500 creatures that live in the dark depths of the world's oceans - much more than scientists had expected (Photo: David Shale).
The creatures - the majority of which have never been seen before - inhabit the dark waters below depths of 200m (650ft), where natural light barely penetrates (Photo: Bunzow/Corgosinho).
They include the Coryphaenoides brevibarbis – or rat-tail fish – that has growth bands that can be counted like tree rings to tell the age of the fish (Image: Rebecca Hunter).
This sea cucumber, Enypniastes, lives on animal droppings from the sunlight layer above, while others have adapted to survive by breaking down methane or even oil (Photo: Larry Madin).
As deep as 5,000m (16,500ft) below the surface - at pressures that would kill an unprotected human - scientists found mud teeming with crabs, starfish and corals.
Amongst the more unusual finds was a 2m-long (6ft 6in) cirrate octopod (Photo: Mike Vecchione).
The octopod is an eight-limbed creature nicknamed "Dumbo" because of the large, elephant ear-like fins it uses to swim (Photo: Mike Vecchione).
Scientists also discovered a "bizarre" elongated orange animal identified as Neocyema living at 2,000-2,500m (6,500-8,200ft) below the surface (Photo: David Shale).
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