A New ‘Ghost Shark’ Species Was Just Discovered Lurking in the Deep Sea Off Costa Rica
Researchers identified the fish using a mix of traditional anatomy and modern DNA analysis
Credit: Naidely Valeria Vidaurre Quesada
NEED TO KNOW
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Researchers identified Rhinochimaera costaricana, a new species of ghost shark, in deep waters off Costa Rica
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The species was distinguished by unique physical traits and DNA analysis, marking a new branch on the tree of life
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Experts highlight the need to study deep-sea life as ecosystems face threats from fishing, mining and climate change
The deep sea is still full of surprises. Its latest is a fish that scientists have discovered is completely new to science.
Researchers have formally described a new species of "ghost shark," a group of deep-sea fishes known scientifically as rhinochimaeras, according to Forbes . The animal, named Rhinochimaera costaricana , was found in the sunless depths off the Pacific coast of Costa Rica, hundreds of meters below the surface.
A deep sea ghost shark with a pointed snout and winglike fins viewed laterally Credit: Naidely Valeria Vidaurre Quesada
The nickname is a bit misleading, as ghost "sharks" aren't sharks at all. Per Forbes, they belong to an ancient group of cartilaginous fishes called chimaeras, which branched off from the shared ancestor of sharks and rays hundreds of millions of years ago and have been quietly doing their own thing ever since.
Researchers had just three male specimens, netted off Costa Rica's Pacific coast between 2000 and 2023 and measuring roughly 30.5 to 32.6 inches long. Because deep-sea creatures tend to evolve similar body plans to endure the crushing pressure, cold and darkness of their habitat, telling one apart from another often comes down to millimeters. The team recorded 49 separate body measurements and compared them against more than 90 specimens from the three previously known species in the genus.
What set the Costa Rican fish apart was a specific mix of features: a shorter snout, a taller spine ahead of its first dorsal fin, more space between its fins and fewer of the tiny bumps, called tubercles, that dot the tail. To be sure, the researchers went beyond anatomy, sequencing a stretch of DNA nicknamed a "genetic barcode." Those sequences diverged from the fish's closest relatives by 3.9 to 4.7% — comfortably past the line scientists use to call something a separate species — and additional analyses agreed the animal represents its own lineage.
The result is a genuinely new branch on the tree of life, and, notably, the first member of its genus ever described from the Eastern Pacific.
As Forbes noted, the deep ocean covers most of the planet yet remains one of Earth's least-mapped frontiers, so a species can't be protected if no one knows it's there, a growing concern as fishing, resource extraction and climate change reach ever deeper.
Read the original article on People
