Four New Deep-Sea Worms Help Researchers Solve Evolutionary Mystery

Four new species of deep-sea flatworm-like animals were recently discovered living near deep-sea cold seeps, hydrothermal vents, and whale carcasses off the coasts of California and Mexico. Scripps Institute of Oceanography researchers say the discovery of this strange looking creature belongs within a classification that previously contained only a single species.

The new species – Xenoturbella churro, named for its resemblance to the popular Spanish fried-dough pastry – measures roughly four inches long.

"The findings have implications for how we understand animal evolution," Scripps marine biologist Greg Rouse, lead author of the study, explained in a news release. "By placing Xenoturbella properly in the tree of life we can better understand early animal evolution."

Since the first species, Xenoturbella bocki, was discovered in 1950 near Sweden, the worm-like genus Xenoturbella had been hard to place in the hierarchy of the animal kingdom. However, the recent study puts them firmly "near the base of the evolutionary tree of bilaterally symmetrical animals."

In order to properly identify the species, researchers analyzed nearly 1,200 of the animal's genes. Xenoturbella have only one body opening, the mouth, and it lacks a brain, gills, eyes, kidneys or an anus. On an evolutionarily scale the creatures are rather simple beings that have shed a variety of their biology over time.

The findings were recently published in the journal Nature.