‘Loki the Sea Cucumber’ among 57 new marine species discovered within just 2 weeks in Argentina’s submarine canyon

Scientists examining samples from a deep-sea canyon off of Argentina’s coast identified 57 marine species previously unknown to science. The scientists discovered the new species and five new genera in just two weeks of exploration. The exploration was led by the Nekton Ocean Census in partnership with the Schmidt Ocean Institute.

Among the key findings is “Loki the Sea Cucumber”, a deep sea echinoderm of the Peniagone genus. Scientists nicknamed it Loki due to its horned appendages, which they said resembled the Norse god of the same name.

Loki was found at a depth of 2,577 metres. The sea cucumber represents one of up to 10 new holothurian species discovered by the scientists. It is about 100 mm in length and 30 mm wide.

What other species did the scientists discover?

The scientists explored the Mar del Plata Submarine Canyon in the South Atlantic Ocean. The submarine canyon is over 3,500 meters deep. This makes it about twice as deep as the Grand Canyon.

The specimens were collected during an expedition in August 2025 and were examined by 20 researchers in a workshop in Buenos Aires this year.

Out of the 57 newly identified species, 20 are copepods and 22 are echinoderms, commonly known as sea cucumbers. Among these are also 14 cnidarians, commonly known as sea pens, stony corals and octocorals.

The study also identified five new scientific genera. These include corals, sea cucumbers and crustaceans.

Among the newly identified species is a copepod collection. During the study, taxonomists examined only 10% of these tiny creatures. Yet, each specimen that was examined was a new species. The collection resulted in the discovery of 20 new species and one new genus.

Another highlight of the discovery was the 14 new species of corals. This could lead to the identification of two potential new genera and a potential new family unknown to science. The specimens are awaiting further genetic analysis.

The study found a vivid orange-red octocoral. It was discovered at a depth of 1,954 meters. This could provide crucial information on habitat-forming deep-sea ecosystems.

Scientists discovered a copepod between 1,909 and 2,625 meters below the ocean’s surface. They also identified a bright purple holothurian.

Why were so many discoveries made in this canyon?

The Mar del Plata Canyon sits at an unusually dynamic part of the South Atlantic. The region sees two major ocean currents meet, with the warm and salty Brazil Current and the colder and much more nutrient-rich Malvinas Current. These ocean currents move nutrients, heat and organisms around.

The canyon creates a complex three-dimensional landscape on the seafloor. This creates habitats that can support several organisms, including corals and sponges.

Scientists have found rich ecosystems in the region earlier as well. During 2012 and 2013, several new species were found in expeditions using only fishing nets and trawls.

How did they explore the canyon?

The expedition used a remotely operated vehicle, SuBastian. The vehicle was operated from the research vessel Falkor.

The remote while remains connected to the main vessel, unlike crewed submarines. This allows scientists to control it from the surface, collect samples and also watch live.

During this expedition the remote vehicle provided the first in-situ observations of the massive seafloor. The 21-day expedition was also live streamed and attracted nearly 22 million views across platforms.