Its fuzzy, winter-white coat might look at home in the Himalaya, but the yeti crab was discovered skittering around hydrothermal vents about a mile and a half (2.4 kilometers) under the South Pacific off Easter Island (map) in March 2005.
The 6-inch (15-centimeter), blind crustacean—officially Kiwa hirsuta—is among the more than 6,000 new species discovered during the Census of Marine Life, a ten-year effort to document all sea life that concluded Monday.
The project's 500-plus expeditions have also amassed a visual legacy as unique as the organisms uncovered—from which National Geographic News has selected these images as the 13 best of the census. (Read more about the yeti crab.)
Photograph courtesy A. Fifis, IFREMER
A 2005 Census of Marine Life expedition to the Arctic Ocean captured a so-called sea angel, Clione limacina, at about 1,148 feet (350 meters) underwater. Despite its nickname, this little angel apparently doesn't mind showing a little skin: It's actually a naked snail without a shell, scientists said in December 2009.
Such marine snails—most of them the size of a lentil—are widely eaten by many species, making them the "potato chip" of the oceans, biologist Gretchen Hofmann, of the University of California, said in a 2008 statement.
Photograph courtesy Kevin Raskoff, Monterey Peninsula College
Squid? Worm? Initially, this new species—with bristle-based "paddles" for swimming and tentacles on its head—so perplexed Census of Marine Life researchers that they threw in the towel and simply called it squidworm.
Found via remotely operated vehicle about 1.7 miles (2.8 kilometers) under the Celebes Sea (see map) in 2007, the four-inch-long (ten-centimeter-long) creature turned out to the first member of a new family in the Polychaeta class of segmented worms.
At the slightest touch, these "Christmas trees" temporarily disappear down a hole faster than you can say "Grinch." It's a defense mechanism of the Christmas tree worm, most of which resides in a tunnel it carves into live coral.
Photographed off Australia's Lizard Island (map) by a Census of Marine Life expedition, the two blue trees are actually a single worm's "crowns"—each spiral is a series of tentacles used in breathing and in passive feeding on tiny, floating foodstuffs.
Photograph courtesy John Huisman, Murdoch University
Affectionately nicknamed "Mr. Blobby," this fathead sculpin fish was discovered in 2003 in New Zealand during a Census of Marine Life expedition, according to the Australian Museum in Sydney.
Fathead sculpins—named for their large, globe-like heads and floppy skin—live in the Atlantic, Indian, and Pacific Oceans at depths of between about 330 feet (100 meters) and 9,200 feet (2,800 meters).
Now preserved in 70 percent ethyl alcohol at the Australian Museum, Mr. Blobby's nose has shrunk—"and he no longer retains his 'cute' look," according to the museum's website.
Photograph courtesy Kerryn Parkingson, NORFANZ
Dumbo of the Deep
Found in 2009, a deep-sea "Dumbo octopus" (pictured) may look like it's all ears—but the protrusions are actually fins that help propel the animal through the darkness a mile (1.6 kilometers) under the sea.
Netted during a Census of Marine Life expedition to the Mid-Atlantic Ridge, this Dumbo is among the thousands of census-documented creatures that live without ever knowing sunlight.
Reaching six feet (two meters) in length and weighing 13 pounds (6 kilograms), the jumbo Dumbo species is the largest of the octopus-like creatures of the mollusk genus Grimpoteuthis.
This blind lobster, discovered in 2008 during a Census of Marine Life expedition, was given the scientific name Dinochelus ausubeli, which is derived from the Greek dinos, meaning terrible and fearful; chela, meaning claw; and ausubeli, in honor of Jesse Ausubel, a co-founder of the Census of Marine Life.
The lobster likely uses its exaggerated claw, or cheliped, to defend against other crustaceans.
Photograph courtesy Tin-Yam Chan, National Taiwan Ocean University, Keelung
Collective Jellyfish Cousin
This pink siphonophore, Athorybia rosacea, was found during a Census of Marine Life expedition in the Sargasso Sea (see map) in the eastern Atlantic.
"Stunningly beautiful but deadly," the Gulf of Mexico's Venus flytrap anemone (pictured) acts much like its terrestrial namesake, stinging its prey with an array of tentacles, according to the U.S. Geological Survey. (See pictures of more stinging and toxic sea creatures.)
The species' native Gulf—along with the Mediterranean Sea, Chinese waters, the Baltic Sea, and the Caribbean Sea—are the ocean regions most under threat from human activities, according to Census of Marine Life scientists.
For instance, nutrients in sewage and fertilizer washed from the land are degrading these marine habitats by creating oxygen-free "dead zones," the report says.
Photograph courtesy Ian MacDonald, Florida State University
Discovered in 2005, this new physonect siphonophore is a colonial animal, made up of many repeated units—such as the nectophores, or swimming bells, on the right half above, which provide propulsion for the colony.
Many specimens of Marrus orthocanna were observed between 980 feet (300 meters) and 4,900 feet (1,500 meters) deep during a 2009 Census of Marine Life expedition.
Reaching 10 feet (3.1 meters) in length, some siphonophores are among the largest animals in the deep sea, experts say.
Photograph courtesy Kevin Raskoff, Monterey Peninsula College
Baby Slipper Lobster
This baby slipper lobster, found during a Census of Marine Life expedition, is completely transparent, though as the creature grows, a thick shell will cover it.
Researcher Niel Bruce of the Museum of Tropical Queensland studies marine specimens in a lighted aquarium off Australia's Lizard Island (see map) in an undated picture.
The massive Census of Marine Life inventory "was urgently needed for two reasons," final census report author Mark Costello said in a statement.
"First, dwindling expertise in taxonomy impairs society's ability to discover and describe new species. And secondly, marine species have suffered major declines—in some cases 90 percent losses—due to human activities and may be heading for extinction, as happened to many species on land."
Photograph courtesy Gary Cranitch, Queensland Museum