Creatures of 'The Deep'

This large, dark and velvety ball was discovered in 1993 by MBARI researchers in California. It is so different from other jellies that biologists had to create a new sub-family for it, called the Tiburoniinae, after the Tiburon, the robot that discovered them.

To capture its prey, it does not use stinging tentacles, as do the majority of jellies. Rather, it deploys long fleshy arms whose number varies, curiously, between four and seven. Very little is currently known about this creature.

The behaviour and biology of this finned octopus are still largely uncertain. They are frequently found close to the bottom – up to a depth of 5,000m – in all the world’s oceans, though they can also adventure rather far within the water column. The largest specimens can reach 1.5m in size.

This miniscule jelly – it’s only 4cm in diameter – is generally found swimming very near the bottom, up to a depth of 3,500m. Most likely its myriad tentacles (between 1,000 and 2,000) are used to capture small benthic crustaceans.

Like a prehistoric tadpole popping suddenly before the ROV camera, this fish – also known as the threadfin snailfish – with its face perforated with large sensory pores seems to confirm the myth of the deep sea being a haven for fossil creatures that have remained unchanged since the dawn of time.

Despite its strange looks, the 15cm-long creature does not number among the oldest sentinels of our planet, as do the horseshoe crab and the coelacanth, whose fossil records date back more than 250 million years.

This amusing little octopus almost looks like a character out of a Japanese cartoon. Researchers have already described 14 species of Grimpoteuthis, but beyond the taxonomic description made on the basis of animals captured by trawlers, these octopi for the most part are still enigmatic.

They are often observed resting on the bottom, with their mantle spread around them. What are they doing there, sitting so quietly in the dark? Nobody knows.