Purple socks and churros: Weird worms earn place on tree of life

Scientists have just identified four very weird-looking worms.

Led by researchers at the Scripps Institute of Oceanography at the University of California-San Diego, the science team helped correctly identify the worms using genetic analysis. One of the species looks a lot like purple socks. Another looks so much like the churro pastry that the worm was named after it. The findings are documented in the Feb. 4 issue of the journal Nature.

The worms can be found in the depths of the ocean, near hydrothermal vents, cold seeps, and whale carcasses. The scientists suspect that the worms call these cold, dark depths home because of the clams and mollusks that live there.

The worms really like eating clams and mollusks, but they have very simple bodies: they only have one body opening, and no eyes or gills. The biggest of the worms, Xenoturbella monstrosa in Monterey Bay, Calif., measures eight inches long. The smallest worm, Xenoturbella hollandorum, is tiny, measuring just one inch long.

Worms like these were first discovered in 1949, and have bothered scientists ever since because they don’t fit into neat definitions. The first discovered worm, Xenoturbella bocki, was initially classified as a flatworm, then later as a simplified mollusk. That definition was thrown off when scientists found out that mollusks form part of these worms’ diet.  

The research team has classified the newly discovered worms as evolutionary simple members of the tree of life. They have categorized them with bilaterally symmetrical animals, which means that they have a line down the center that separates their matching sides.

The team performed several deep-sea expeditions to find these weird and wonderful worms, and looks forward to finding more.

“I have a feeling this is the beginning of a lot more discoveries of these animals around the world,” study lead author Dr. Greg Rouse explained in a press release.