New Ghost Shark Species Found in Costa Rica's Deep Pacific

Scientists have formally identified a new species of deep-sea ghost shark living in the Pacific waters off Costa Rica.

It took more than two decades, three preserved specimens, and a trip to a London museum archive to confirm it.

What Scientists Actually Found

The species has been named Rhinochimaera costaricana, after the country where it was collected.

It belongs to a little-known group of cartilaginous fish called long-nosed chimaeras, commonly nicknamed ghost sharks, which are related to sharks and rays but form their own distinct branch of fish that has existed for hundreds of millions of years.

The description was published June 10 in the journal Zootaxa, led by University of Costa Rica biology student Naidely Valeria Vidaurre Quesada, according to El-Balad's reporting on the paper.

Researchers from Costa Rica's Fisheries and Aquaculture Institute and Brazil's Federal University of Pará also worked on the study.

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Three Fish, Twenty-Three Years, One Confirmation

The specimens behind the discovery were not collected in a single expedition.

The first came from near Isla del Caño in 2000. The other two surfaced off Cabo Blanco, Puntarenas, in 2023.

All three were male, measuring between 775 and 830 millimeters long, and were recovered from depths of 390 to 787 meters, El-Balad reported.

Two of the three specimens were originally preserved by INCOPESCA biologists during unrelated fisheries research, years before anyone suspected they belonged to an undescribed species.

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🤖 AI Generated Image

The Genetic Gap That Settled the Question

Identifying a new species from old specimens isn't just a matter of looking at one fish and deciding it looks different.

Researchers compared the Costa Rican specimens against the genus's three previously known species: R. africana, R. atlantica, and R. pacifica.

Genetic sequencing showed a 3.9% difference from R. africana, 4.5% from R. atlantica, and 4.7% from R. pacifica, according to El-Balad's account of the paper's findings.

Combined with physical traits the team measured directly, those genetic gaps were what ultimately separated Rhinochimaera costaricana from its closest relatives, rather than morphology alone.

To rule out any chance the species had already been named decades earlier and overlooked, Vidaurre Quesada also traveled to London's Natural History Museum to check historical global archives before the paper was finalized.

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Why a Fish Nobody Has Seen Alive Still Matters

Rhinochimaera costaricana is now the 12th recognized species in the Rhinochimaeridae family, up from 11, and the fourth in its specific genus.

None of the three specimens used to describe it were observed alive in their natural habitat. Each was a preserved fish pulled from cold storage, not a live sighting in the deep Pacific.

That distinction matters for what the discovery actually represents. It isn't a story about spotting something new in the water — it's a story about how much already sits in scientific collections, unidentified, waiting for the right combination of genetics and patience to be recognized.

Scientists who study the genus have noted the species may also extend to waters off Peru, based on the same paper's geographic findings, with researchers suggesting it could possibly reach the Galápagos Islands as well, though that range remains unconfirmed.

For a stretch of Pacific seafloor most people will never see, it's one more sign of how much remains undocumented below the surface.

Key Takeaways

• Scientists identified Rhinochimaera costaricana, a new deep-sea ghost shark species, in Costa Rica's Pacific waters.

• The discovery was published June 10 in the journal Zootaxa, led by Naidely Valeria Vidaurre Quesada of the University of Costa Rica.

• The description relied on three male specimens collected between 2000 and 2023 at depths of 390 to 787 meters.

• Genetic differences of 3.9% to 4.7% from the genus's three known species confirmed it as distinct.

• The species brings the Rhinochimaeridae family to 12 recognized species and may also occur off Peru and possibly the Galápagos.

Sources

• The Tico Times — Scientists Discover New Deep-Sea Ghost Shark Species Off Costa Rica

• El-Balad — Naidely Valeria Vidaurre Quesada Describes Deep-Sea Ghost Shark Costa Rica Species

• The Costa Rica News — Scientists Discover New "Ghost Shark" Species in Costa Rica's Deep Waters

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