A dark, disc-shaped fish hauled up by accident in a deep-sea shrimp trawl has turned out to be a species new to science — and the first electric ray of its genus ever confirmed in the northern Indian Ocean.

  • 9 specimens examined to confirm the new species
  • 400 to 700 meters: the depth range where the rays were caught
  • 1st confirmed record of the genus Tetronarce in the northern Indian Ocean
  • Named Tetronarce ramanamurthyi, honoring a leading Indian ocean scientist

How fishermen found a new species

The rays turned up as bycatch in deep-sea trawl fisheries targeting red shrimp off the southeastern Arabian Sea. Researchers collected the specimens during routine fish-landing surveys at the Sakthikulangara Fishing Harbour in Kerala — the kind of unglamorous dockside fieldwork that regularly turns out to be exactly where new marine species get found.

An international team from the Zoological Survey of India, San Jose State University, the South African Institute for Aquatic Biodiversity and the California Academy of Sciences examined the specimens together. Genetic testing of two mitochondrial genes confirmed the rays formed their own distinct evolutionary lineage, clearly separated from every other known electric ray species worldwide.

What makes this ray different

Scientists named the new species the Arabian Black Electric Ray, for its uniform dark bluish-black to dark brown upper body and contrasting whitish underside. Unlike its closest relatives, it lacks small skin bumps around its breathing holes, and it has a disc noticeably wider than it is long, a distinctive mouth-to-nostril ratio, and smaller, kidney-shaped electric organs.

Those electric organs are the whole group's claim to fame. Torpedinidae rays, commonly called electric or torpedo rays, generate electric shocks strong enough to stun prey and deter predators using modified muscle tissue near the head — a trick few other fish families have evolved.

"The discovery highlights how much biological diversity remains hidden in the Indian Ocean's deep-sea ecosystems," the research team wrote in their formal species description, published in the journal Zootaxa.

A name that honors ocean science

The species carries the name Tetronarce ramanamurthyi in honor of Dr. M.V. Ramana Murthy, Mission Director of India's Deep Ocean Mission and Director of the National Centre for Coastal Research, in recognition of decades of contributions to Indian marine science.

Beyond the honor, researchers say the find has a practical purpose. It is a reminder that commercial bycatch — fish caught unintentionally while targeting something else entirely — deserves close scientific attention. Deep-sea trawlers already sweep through habitats researchers rarely visit directly, and routinely checking what comes up in those nets is becoming one of the more reliable ways to document species that would otherwise go completely unrecorded.

Why deep-sea surveys keep finding surprises

The southeastern Arabian Sea sits at depths most research vessels rarely sample directly, which is exactly why a commercial fishing harbor turned out to be the discovery point rather than a dedicated scientific expedition. Marine biologists increasingly argue that partnering with existing fisheries monitoring, rather than relying solely on expensive survey cruises, is one of the fastest ways to document deep-sea biodiversity before habitats change.

With one new ray now formally named and cataloged, researchers say the next step is figuring out how widely it actually ranges across the Arabian Sea, and what role it plays in a deep-sea food web that, until this year, nobody knew included it at all.