Scanning the depths off the Philippines in 2007, an undersea robot beamed back video of a worm—or was it a squid, or a worm eating a squid?—with spiraling appendages, iridescent „oars,“ and a feathery „nose.“ „What's that?“ said scientists of the tentacle-headed swimmer. Now they know.

„When the image came onto the screen, everyone said, Oh my gosh, what's that?“ recalled marine zoologist Laurence Madin of the Woods Hole Oceanographic Institution in Massachusetts.

Thanks to a new study co-authored by Madin, we now have the answer. The animal—as suspected—turned out to be a bizarrely bedecked marine worm totally new to science. (See marine-worm pictures.)

The paper, published Tuesday in the journal Biology Letters, describes the new species at length for the first time and officially christens the creature Teuthidodrilus samae, or „squid worm of the Sama“—the Sama being a culture with ties to Philippine islands not far from the discovery site.

(Related: „Large, ‚Glamorous‘ New Glowing Squid Found.“)

Relatively long, at nearly four inches (nine centimeters), the new annelid worm earned its moniker with a head that looks as if it's covered in tentacles.

Its front end bristles with eight arms used for breathing—each as long as the worm's entire body—and two long, loosely coiled appendages employed for feeding.

As if that weren't enough hardware, six pairs of feathery sensory organs—the squid worm's collective „nose“—protrude from the new species' head. And along the length of its body, the worm has iridescent „paddles“ for propulsion.

Whatever it is, it's „definitely flamboyant,“ said Kristian Fauchald, curator of annelid worms at the US. National Museum of Natural History in Washington, D.C., who wasn't part of the study.

(Related: „Alien-like Squid With ‚Elbows‘ Filmed at Drilling Site.“)

Squid Worm Caught in Full Evolutionary Flower?

Beyond its appearance, the squid worm fascinates scientists in part because its odd features suggest the worm may be a transitional form—a species caught in a burst of evolutionary adaptation as it straddles two very different habitats, said study co-author Karen Osborn, an evolutionary biologist at the University of California, Santa Cruz.

Observed between 1.2 and 1.8 miles (2 and 2.9 kilometers) below the ocean surface, Teuthidodrilus samae lives neither on the seafloor nor in the sunny shallows.

Instead, the worm inhabits a dark in-between realm, where the limited observations done so far show the worm feeding off plankton and other nutritious detritus in the water.

Whatever the cause of the squid worm's chimerical form, it apparently works. „Numerous“ specimens were observed during just a few dives, the study authors write—suggesting Teuthidodrilus is common and thriving in the region.

And its homely charms apparently work on humans, or at least on worm curators.

„It has done all sorts of peculiar things to its body,“ Fauchald said. „I'm delighted by it.“

Traci Watson for National Geographic News Published November 24, 2010