The research ship Okeanos Explorer recently found a very unusual octupus very deep in the ocean. That 8-limbed cephalopod is ghostly white -- lacking pigment. It is also different in several ways from those the ship's scientists have seen before, and may be an entirely new species.

The discovery took place on the ship's first operational dive of the 2016 season, on February 27. The vessel, which belongs to the National Oceanic and Atmospheric Administration (NOAA), was looking at depths of more than 4,000 meters, northeast of a location in the Hawaiian Archipelago called Necker Island, or Mokumanamana.

This was the idea: To bring back basic information on whether Necker Island is related to Necker Ridge, which is a thin feature that runs for more than 400 miles and sticks out beyond the United States' current exclusive economic zone (EEZ).

The researchers wanted to gather geological samples from the ridge in order to see if they are made up of the same minerals and other materials as samples from Necker Island. A remotely operated vehicle (ROV) called Deep Discoverer also conducted a survey of the biological groups in the same area.

The ROV at 4,290 meters was crossing a flat, rocky area dotted with sediment, when it ran across a distinctive octupus on a rock. It was so different, actually, that it was dissimilar from any in published records and was biding its time at the greatest depth known for an octupus of this size and general description.

Octupuses in the deep seas are known to be in two groups: (1) finned, or cirrate octupods (another name for octupuses), known as "dumbo" octupods because of their ear-like fins. They also have cirri (slender filaments) that are like fingers and are related to the suckers on their arms or (2) incirrate octupods, which have neither fins nor cirri and look a good bit like octupuses that live in shallow water, which are those we've all seen more often.

The octupus which the ROV captured in detailed images on that first dive was an incirrate. It also had suckers in a single series on each arm, rather than in two lines. Most unusual of all, though, it did not have any pigment cells, known as chromatophores. Those are typical of cephalopods in general. It has a ghost-like appearance. Also, it wasn't especially muscular.

This octupus is almost definitely undescribed and a unique species, and might not be a member of any described genus.

Octupuses of the cirrate, or dumbo type, have been known to live at depths of more than 5,000 meters. But incirrates have been reported at no depths greater than 4,000 meters.

After the ROV returned the images and NOAA research scientist Michael Vecchione analyzed them, he reached out to colleagues Louise Allcock (who is on a British research ship near Antarctica right now) and Uwe Piatkowski (who is from Germany). All three agreed that the octupus was unusual and that it was found at a depth record for incirrate octupods.

At the moment, the three scientists are considering combining the new finding with some other observations about very deep-ocean incirrate octupuses taken by a German ship in the eastern Pacific and submitting it for publication in a journal.

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