Ocean Literacy · Deep-Sea Biodiversity

Buenos Aires Workshop Identifies 57 New Deep-Sea Species from Argentina’s Mar del Plata Canyon

Twenty taxonomists spent two weeks on samples from the 2025 Falkor (too) expedition. They got through only part of the material, and the organisers expect the count to rise.

By SEVENSEAS Media | Ocean Conservation

A year after a live-streamed dive in Argentina’s Mar del Plata Canyon turned an orange sea star into an internet celebrity, the animals actually collected on that cruise have produced a more substantial result. Scientists working through the samples in Buenos Aires in July identified 57 species and five genera they consider new to science, according to the Nippon Foundation-Nekton Ocean Census and Schmidt Ocean Institute, which announced the findings on 1 October.

The Species Discovery Workshop ran from 13 to 24 July at Universidad Maimónides and brought together 20 taxonomists and early-career researchers from Latin America and Europe. CONICET, Argentina’s national science agency, says its researchers Martín Brogger and Valeria Teso coordinated the work locally. Most of the material came from Talud Continental IV, the 21-day expedition that Dr Daniel Lauretta of CONICET led aboard Schmidt Ocean Institute’s research vessel Falkor (too) in July and August 2025. The team also worked on older samples from the Talud Continental I–III campaigns of 2012 and 2013.

What the 57 are, and what “new” means here

The organisers break the total down as 20 copepods, 22 echinoderms (sea cucumbers and crinoids), 14 cnidarians (octocorals, sea pens and stony corals) and a single scaphopod, the small mollusc known as a tusk shell. The five new genera are spread across corals, sea cucumbers and crustaceans. Among the corals, they also report two possible new genera and a possible new family, both still awaiting genetic analysis.

It helps to be precise about the claim. At this stage a “new species” is a specimen that experienced taxonomists have judged to be undescribed, logged to Ocean Census NOVA, the programme’s open-access database for newly discovered marine life. Giving each one a formal name means a published description, designated type specimens and peer review, which usually takes years. That is why every animal in the highlights still carries “sp.” after its genus. CONICET’s own announcement describes 57 as the figure for now.

The number has already moved once. When the cruise ended in August 2025, Schmidt Ocean Institute said the scientists suspected more than 40 new species. Closer study raised that to 57, and there is a lot of material left. The copepods make the point most clearly. These are harpacticoids, crustaceans usually around a millimetre long or less, and the workshop examined only about a tenth of the copepod samples. According to the organisers, every specimen examined was new to science, giving 20 species and one genus. That may say as much about how little deep-sea copepods have been studied as about the canyon itself.

Loki, a purple sea cucumber and a red coral

The animal the organisers chose to lead with is a sea cucumber in the genus Peniagone, filmed at 2,577 metres and nicknamed Loki for the horn-like appendages on its back. Francisco Alonso Solís-Marín and Mariano Martinez identified it, and it is one of up to ten new sea cucumber species recognised at the workshop.

The same pair of taxonomists worked on a bright purple sea cucumber in the genus Benthothuria, photographed resting on the canyon floor. Among the corals, the highlights are a red-orange octocoral in the genus Orstomisis, recorded at 1,954 metres on soft sediment and identified by Ralf Cordeiro and Daniel Lauretta, and a sea pen in the genus Pseudumbellula, identified by Jessica Risaro and Pablo López-González. The organisers describe both as part of the canyon’s habitat-forming deep-sea coral communities, which shelter other animals.

A canyon where two currents meet

The Mar del Plata Canyon lies about 300 kilometres off the city of the same name and drops below 3,500 metres. It sits in the Brazil–Malvinas Confluence, where the warm Brazil Current runs into the cold, nutrient-rich Malvinas Current coming up from the sub-Antarctic, and the mixing makes the area unusually productive. During the 2025 dives the remotely operated vehicle SuBastian, rated to 4,500 metres, filmed deep-sea coral reefs and a dense field of red mushroom coral at about 1,500 metres.

Those dives were streamed live. Schmidt Ocean Institute puts the live audience at about 4 million, roughly three-quarters of them in Argentina, and says viewers also saw shoes, plastic bags and fishing gear on the canyon floor. Much of the attention went to the orange sea star, which the organisers say was not thought to be a new species and was left undisturbed.

Too few taxonomists

Collecting the animals is only half the job. Someone then has to tell one undescribed copepod or sea pen from another, and the workshop format, which puts specialists in one room with the specimens for two weeks, is how Ocean Census tries to speed that up. Lauretta put the case this way:

“International cooperation in taxonomy is critical, especially in groups with few active specialists.”

Dr Daniel Lauretta, Principal Investigator, CONICET and Museo Argentino de Ciencias Naturales

He also says the workshop trained local early-career taxonomists working on deep-sea fauna. The physical specimens, along with the older Talud Continental material, will stay in Argentine collections, including the Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” in Buenos Aires. In CONICET’s announcement, Lauretta adds that the agency employs the largest community of taxonomists in Argentina, spread across the country and covering a wide range of groups.

Ocean Census, launched in 2023 by The Nippon Foundation and Nekton, says only about 240,000 marine species have been formally documented and that millions more are thought to remain undiscovered. Michelle Taylor, its head of science, credits the speed of the Buenos Aires result to collaborative taxonomy and to linking Latin American specialists with international experts through the NOVA platform.

The next canyon

Lauretta’s group and Schmidt Ocean Institute are planning a return in February and March 2027. According to CONICET, the expedition, Talud Continental V, will target the Ameghino and Almirante Brown canyons off Chubut province, about 600 kilometres from the coast, in a little-explored part of the southwest Atlantic where vulnerable marine ecosystems are known to occur. It will also be streamed live. Lauretta told CONICET that the collaborations formed in Buenos Aires are what will allow the Mar del Plata species to be formally described. Until then, the 57 remain a provisional count, and the 90 per cent of copepod samples nobody has examined yet are still waiting.

Read CONICET’s announcement (in Spanish), and find newly logged species on the Ocean Census website.

SEVENSEAS Media · Conservation Journalism for the Ocean