A deep-sea chimaera of an ecosystem sits off the Pacific coast of Costa Rica. A Jaco scar is a methane leak, where the gas seeps out of the sediment into the ocean water, but the leak is not as cold as before. Instead, geochemical activity gives the trail lukewarm water that enables organisms to traditionally call it home from both cold seeps and hot hydrothermal vents.
an inhabitant of the mark is a Newly identified species of small, purple fish called eelpoutFirst described on January 19 zootaxa, This fish is the first vertebrate species found on the scar and could help scientists understand how the unique ecosystem evolved.
Science News Headlines, delivered to your inbox
Titles and summaries of the latest science news articles, delivered to your email inbox every Thursday.
Thank you for signing up!
There was a problem signing you up.
The Jaco Scar was discovered during an exploration of a known area of methane leakage off the Costa Rican coast and named after the nearby town of Jaco. It’s “a really diverse place,” says Lisa Levine, a marine ecologist at the Scripps Institution of Oceanography in La Jolla, California, with many different organisms living in different microclimates.
Levin was on one of SCAR’s first expeditions but was not involved in the new study. She recalls the team finding and collecting the fish during this initial excursion, but the researchers did not recognize it as a new species.
Several more specimens were trapped during subsequent submersible dives. Charlotte Seid, an invertebrate biologist at Scripps who is working on a checklist of organisms found in Costa Rican oysters, brought the fish find to Scripps ichthyologist Ben Frable for formal identification.
Frable says he knew the fish was an eelpout. They look exactly as one would expect based on their name: scowling eels, although they are not true eels. But he was having trouble determining which type. Eelpout are a diverse family of fish that includes about 300 species that can be found at various ocean depths around the world.
Because the physical differences between species can be subtle, they are “kind of a tricky group” to identify, Freble says. “I really wasn’t getting anywhere.” So the team went to expert Peter Rask Möller at the Natural History Museum of Denmark in Copenhagen, sending him X-rays, pictures and eventually one of the fish specimens.
Moller narrows enigmatic eelpout to genus pyrolycus, which means “fire wolf.” Turns out, the tool, called the dichroic key, that Freble was using to identify the samples was old, having been made before pyrolycus was described in 2002. “I didn’t know that genus existed,” says Frable.
because the other two are known pyrolycus The species live far out in the western Pacific and have different physical characteristics, the team dubbed the mystery fish P Jaco A new species.
The first eelpouts likely evolved in colder waters, says Frable, but many have made their home in the scalding waters of hydrothermal vents. Of the 24 known fish species that live only at hydrothermal vents, “13 of them are eelpouts,” Frable says.
New discovery raises questions about how pyrolycus The species came to live so far apart. This may have to do with the fact that methane seeps are more common on the ocean floor than previously thought, and if some are hummocky like Jaco Scar, the new species could have used them as refuges when moving east. .
and by comparison P Jaco As for its vent-living relatives, researchers may be able to figure out how it adapted to living in the warm waters of the trail—which could provide clues to how other species that live there do as well.
The eelpout is part of a mix of other species that make up Jaco Scar’s overall ecosystem, for example, clams commonly found in cold seeps and bacteria found in hydrothermal vents. Jaco Scar is a “mixing bowl” of species found in other parts of the world, says Seid. Figuring out how this eclectic bunch interacts is “part of the fun.”