A rare basket star, seen riding on its intricate network of arms, is among a haul of strange and previously unknown deep-sea creatures recently found in the middle of the Atlantic Ocean, scientists announced Tuesday.
Ten potentially new species—including "mountaineering" sea cucumbers and possible "missing links" between invertebrates and backboned animals—were discovered during the six-week expedition.
The voyage, which ended July 3, was the last of the MAR-ECO project, a series of biological surveys of unexplored waters along the Mid-Atlantic Ridge, the underwater mountain range that bisects the Atlantic Ocean from north to south.
Sea cucumbers typically move along the seafloor at a snail's pace. But the MAR-ECO team found this surprisingly mobile individual during their recent expedition to the Mid-Atlantic Ridge between Iceland (map) and the Azores islands (map), scientists announced Tuesday.
Monty Priede, of the University of Aberdeen, thinks the unusual athleticism of this specimen—one of the expedition's ten potential new species—allows the animal to move among grazing areas on steep, undersea mountainsides.
"Nobody had seen [sea cucumbers] in such a complicated environment," he said.
This deep-sea scale worm boasts iridescent scales that flash in deep blue hues, though scientists aren't sure why, since the creature lives in total darkness.
"It shuffles along the seafloor on bristly legs, picking up little bits and pieces," said expedition member Monty Priede.
The strange animal was located last month in the mid-Atlantic using Isis, the U.K.'s deepest-diving remotely operated vehicle (ROV). Isis explored as far down as 12,000 feet (3,600 meters), revealing marine species whose sheer abundance surprised the study team, Priede said.
This newfound creature is part of a group that may represent an evolutionary link between vertebrates and invertebrates, scientists believe.
Previously only a handful of species of the enteropneust acorn worm had been known, and only from the Pacific Ocean. But the recent expedition turned up three potential new species of these "living fossils" along the undersea mountain chain that divides the Atlantic Ocean lengthwise.
"What we're seeing here are the first steps in the evolution of mobile animals, either by crawling or swimming," said marine biologist Monty Priede, of the University of Aberdeen. "This particular white one we observed swimming."
A potentially new species of deep-sea jellyfish tripped the light fantastic for researchers during their recent MAR-ECO expedition to the Mid-Atlantic Ridge.
"This is a special kind [of trachymedusa jellyfish] which, instead of floating around in the middle of the ocean"—as most jellyfish do—"floats just centimeters above the bottom, with its tentacles touching the seafloor," team member Monty Priede said. "This is a very unusual thing."
Another new variety of swimming sea cucumber was spotted journeying along the Mid-Atlantic Ridge during the recent MAR-ECO expedition.
Deep-sea sea cucumbers are normally found on the ocean floor. But the study team saw several species high on steep slopes of the vast underwater mountain range running the length of the Atlantic Ocean.
"We've always thought of them as slow-crawling animals, but they are actually capable of swimming," marine biologist Monty Priede, said. "This is quite important on the Mid-Atlantic Ridge, because otherwise there's a risk of starving if they get stuck on a ledge somewhere."
A rare sea cucumber demonstrates uncharacteristic swimming skill in the blackness of the deep Atlantic.
The creature is one of ten suspected new species found during a recent survey of the region, where the Gulf Stream—a powerful current that carries warm water northeast across the Atlantic—cuts across the Mid-Atlantic Ridge via deep canyons.
The survey revealed extremely diverse and abundant animal life in the area, according to the expedition team. They found very different groups of species living north and south of the Gulf Stream, and on opposite sides of the ridge.
"There were startling differences over short distances," team member Monty Priede said.
A rare species of comb jelly is caught searching for prey during last month's MAR-ECO Atlantic survey.
Comb jellies normally drift around in open water. But "this is a species that specializes in feeding on the deep-sea floor, so again, it is very unusual," said Monty Priede, of the University of Aberdeen.
The MAR-ECO expedition is part of the Census of Marine Life, a ten-year study of deep-sea animal diversity in the world's oceans, which is drawing to a close this year.
Blind, purple, and peculiar, this primitive, deep-sea life-form may be akin to the common ancestor of humans and all other backboned animals, according to scientists.
One of three new species of enteropneust acorn worm discovered during the mid-Atlantic survey, the creature has no eyes, no obvious sense organs, and no brain. "This is about as primitive as you can go," team member Monty Priede said.
But, he added, "they've got a head end and a tail end—the basic body plan of vertebrates." Such living fossils "represent the first mobile animals."
Photograph courtesy David Shale
Missing, Pink Link?
Creatures like this pink, potentially new species of enteropneust acorn worm may have been the ancestors of the first backboned animals, according to expedition member Monty Priede.
The MAR-ECO team captured three likely new species of the primitive worm, each in a different color—pink, purple, and white—and with different body shapes.
The creatures will be sent for DNA analysis to see if they are indeed key evolutionary links between spineless animals and those with backbones.
"This expedition has revolutionized our thinking about deep-sea life in the Atlantic Ocean," Priede said. "It shows that we cannot just study what lives around the edges of the ocean and ignore the vast array of animals living on the slopes and valleys in the middle of the ocean."