An image of a living male Pectinereis strickrott worm captured by scientists. The worm's feather-like parapodia can be seen in yellow (Credit: Ekin Tilic/ CC-BY-SA-2.0)

A new species of ragworm, likened to a living magic carpet, has been discovered in the methane seeps 30 miles (48 km) off the coast of Costa Rica. The rose-colored Pectinereis strickrotti (P. strickrotti) is one of 450 species found in the area since 2009. Forty-eight of them are new to science.

Methane seeps are areas of the seafloor where bubbles of the greenhouse gas escape from rocks or sediment of the seafloor. These seemingly inhospitable ecosystems are home to a wide range of animals that live off food produced by methane-consuming bacteria.

Marine biologist Greg Rouse and his team first spotted the colorful worms in 2009 while exploring the area in a deep-sea submersible called Alvin.

"We saw two worms near each other about a sub's length away, swimming just off the bottom," said Alvin's pilot, Bruce Strickrott, for whom the worm was named. "We couldn't see them well and tried to creep in for a closer look. But it is hard to creep in a submarine, and we spooked them."

Fortunately, when the scientists returned to the area known as Mound 12 in 2019, they saw several more of the worms. This time, they were able to capture clear images and even collect three adult males and part of one female worm. A closer analysis revealed that the tiny creatures were a new ragworm species.

In 2019, the scientists were able to capture many images of the P. strickrotti (Credit: Woods Hole Oceanographic Institute and the Schmidt Ocean Institute. CC-BY-SA-2.0)

Like other ragworms, the P. strickrotti have a row of feather-like parapodia on each side of the body, similar to the legs of a centipede. They also use their hidden claw-shaped jaws to catch unsuspecting prey.

However, in the study published in the journal PLOS One on March 6, 2024, the researchers pointed out many features unique to the P. strickrotti. Ragworms are usually found in shallow waters, but the new species has evolved to live in the deep sea. Additionally, ragworms typically absorb oxygen directly through their parapodia. However, the P. strickrotti have gills atop their parapodia to help with the task. Finally, thanks to the total darkness of the deep sea, the new worms are completely blind. The scientists suspect they use smell and touch to help with navigation. The worm's gorgeous pink color is not crucial for survival in the dark waters. Rouse and his team believe it is probably due to the color of its blood.

"We've spent years trying to name and describe the biodiversity of the sea," Rouse said. "At this point, we have found more new species than we have time to name and describe. It just shows how much undiscovered biodiversity is out there. We need to keep exploring the deep sea and protect it."

Rouse and his fellow researchers plan to explore the methane seeps near Alaska and Chile later this year. Stay tuned for more exciting deep-sea discoveries!