Marine biologists from the Scripps Institution of Oceanography at the University of California, San Diego, and the Centro de Investigación Científica y de Educación Superior de Ensenada have described an unusual new deep-sea worm species with gills found at methane seeps off the Pacific coast of Costa Rica. Named Pectinereis strickrotti, the new species has an elongated body that is flanked by a row of feathery, gill-tipped appendages called parapodia on either side.
Pectinereis strickrotti belongs to Nereididae, a family of over 700 accepted species of segmented, mostly-marine worms.
Commonly called ragworms, these creatures generally known from coastal regions, commonly confined to shallow marine habitats, although they also occur in brackish, freshwater, and even moist terrestrial environments.
However, approximately 10% of the total diversity is known from deep-sea habitats.
These worms have very elongated bodies with rows of bristled parapodia on their sides and a hidden set of pincer-shaped jaws that can be extruded for feeding.
Many species of ragworms also have two distinct life stages: atoke and epitoke.
In these species, the worm spends most of its life on the seafloor, often in a burrow, as a sexually immature atoke, but in their life’s final act they transform into sexually mature epitokes that swim up off the bottom into the water column to find mates and spawn.
Pectinereis strickrotti was first encountered in 2009 at a depth of around 1,000 m (3,280 feet) during a dive in the Alvin submersible.
“We saw two worms near each other about a sub’s length away swimming just off the bottom,” said Woods Hole Oceanographic Institution researcher Bruce Strickrott.
“We couldn’t see them well and tried to creep in for a closer look, but it’s hard to creep in a submarine and we spooked them.”
Finally, in 2018 the team was able to return to Costa Rica’s methane seeps with Alvin.
On a dive to the same spot the worm was first sighted, Dr….
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