A sea cucumber adorned with a pair of horned appendages has earned itself the nickname ‘Loki’ for its resemblance to the Norse god and is one of 57 new marine species identified from the depths of the South Atlantic in just two weeks.

‘Loki the sea cucumber’ was found at a depth of 2,577 metres in the Mar del Plata Submarine Canyon off Argentina. It was identified by taxonomists Francisco Alonso Solis-Marin and Mariano Martinez, and is one of up to ten new holothurian species uncovered during the workshop.

In situ images and video of the animal were captured on the seafloor.

Loki is one of the headline finds from a Species Discovery Workshop led by the Nippon Foundation-Nekton Ocean Census in partnership with the Schmidt Ocean Institute. It also produced five new scientific genera, spanning corals, sea cucumbers, and crustaceans.

The workshop brought together 20 taxonomists and early-career researchers from across Latin America and Europe. It was hosted at the Universidad Maimónides in Buenos Aires in collaboration with Schmidt Ocean Institute, CONICET and the Museo Argentino de Ciencias Naturales.

The team examined deep-sea samples collected primarily during the Schmidt Ocean Institute’s Underwater Oases of the Mar del Plata Canyon expedition in August 2025, carried out aboard the research vessel Falkor (too) using the remotely operated vehicle (ROV) SuBastian.

Using integrated taxonomy techniques to identify specimens rapidly, they logged their discoveries directly onto Ocean Census NOVA, the world’s first open-access data platform for newly discovered marine species. In total, they identified 20 new species of copepods, 22 echinoderms (sea cucumbers and crinoids), 14 cnidarians (octocorals, sea pens and stony corals) and one scaphopod mollusc.

“International cooperation in taxonomy is critical, especially in groups with few active specialists. The species discovery workshop accelerated species identification, the recognition of species new to science, and increased capacity building for local early-career taxonomists working on deep-sea fauna,” said Dr. Daniel Lauretta, Principal Investigator, CONICET, and the Museo Argentino de Ciencias Naturales.

The copepod collection was among the most striking results. Taxonomists examined just 10% of the samples of these tiny but vital crustaceans (Copepoda, Harpacticoida) collected from the Argentina Deep Basin and Mar del Plata Canyon. Every specimen they looked at was new to science, yielding 20 new species and one new genus.

The workshop also identified 14 new species of deep-sea corals and sea pens from the canyon, including two potential new genera and a potential new family, all awaiting genetic analysis.

Highlights include the sea pen Pseudumbellula sp. and the vivid orange-red octocoral Orstomisis sp., which provide crucial data on habitat-forming deep-sea ecosystems.

“Discovering 57 new species and five new genera in just two weeks demonstrates the speed and power of collaborative taxonomy. The deep sea holds some of the least understood ecosystems on Earth. By bringing Latin America’s scientific expertise and international experts together with, as well as connecting them to the open-access Ocean Census NOVA platform, we are drastically accelerating our understanding of marine biodiversity,” said Dr Michelle Taylor, Ocean Census Head of Science.

Operating in a submarine canyon nearly twice as deep as the Grand Canyon, exceeding 3,500 metres, the team used SuBastian to broadcast live video directly to the public. More than four million viewers tuned in to watch sprawling deep-sea coral reefs and fields of mushroom coral at 1,500 metres.

They also saw a bright orange seastar that captured the global imagination for its resemblance to the cartoon character Patrick Star. Despite its fame, “Patrick Star” was not thought to be a new species, and was left undisturbed and unaware of its notoriety.

“The Mar del Plata Canyon expedition captured the public’s imagination when we first live-streamed Argentina’s deep-sea, discovering potential new marine species,” said Dr. Jyotika Virmani, Schmidt Ocean Institute’s Executive Director. “These results show the power when world-class technology and expertise meets international scientific collaboration. By identifying new species, these scientists have advanced our understanding of South Atlantic marine life and, via Ocean Census, ensured that this data is accessible globally.”

Beyond the species count, the workshop was a significant investment in Argentine scientific capacity and regional biodiversity research. It gave early-career researchers and students hands-on training, and allowed knowledge exchange between local and international taxonomic experts.

The specimens processed during the workshop will be permanently housed in national institutional collections, including the Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” (MACN) in Buenos Aires. So too will historical samples from CONICET’s Talud Continental I–III expeditions, a series of deep-sea surveys conducted in 2012 and 2013 off the coast of Buenos Aires Province.

The work is far from finished. Dr Lauretta and his team are planning a follow-up expedition with Schmidt Ocean Institute for February–March 2027, to a different submarine canyon where high endemism is anticipated. New invertebrate samples from that voyage could yield further new species and genera, and will call for more collaborative discovery efforts like this one.

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