Scientists Discover 149 Previously Unknown Marine Species in the Deep Indian Ocean
August 29, 2026
Scientists have uncovered an extraordinary range of previously unknown marine life during an extensive exploration of remote underwater mountains in the central-eastern Indian Ocean. Researchers identified 149 species considered new to science after examining deep-sea ecosystems around Australia’s Christmas Island and the Cocos (Keeling) Islands.
The findings come from two research voyages conducted aboard Australia’s research vessel RV Investigator in 2021 and 2022. Scientists investigated 22 seamounts—large underwater volcanic mountains—along with surrounding deep-ocean areas. The survey covered depths ranging from approximately 94 metres to 5,431 metres.
A hidden world beneath the Indian Ocean
The deep waters explored by the researchers had received comparatively little scientific attention. The expedition documented 1,059 taxonomic groups, including 856 invertebrates and 203 fish. Of these, 149 were assessed as previously undescribed species.
The newly identified organisms represent a remarkable variety of marine life. They include sea stars, sea cucumbers, worms, corals, barnacles, crustaceans and fish. One particularly notable discovery was a deep-sea worm collected at a depth approaching 5,000 metres.
Researchers also encountered a newly documented fish belonging to the greeneye family and a parasitic barnacle, illustrating how different forms of life have adapted to the extreme conditions of the deep ocean.
Extreme conditions did not stop marine life
The animals discovered during the expedition live in an environment where sunlight cannot penetrate, temperatures are extremely low and food supplies are limited.
Seamounts can nevertheless create important habitats because underwater currents interact with their steep geological structures. These conditions can concentrate nutrients and create opportunities for organisms such as filter feeders to survive and reproduce.
Scientists believe the seamounts may also function as ecological stepping stones, helping marine species move between isolated deep-sea habitats.
An extraordinary fossil discovery
The expedition produced another remarkable finding: researchers recovered more than 1,000 shark teeth from a deep section of the ocean floor.
The teeth represent millions of years of shark evolution and included fossils associated with modern and extinct species, including megalodon. Researchers referred to the location as the “Shark Graveyard.”
The discovery provides scientists with an unusual historical record of marine predators that lived in the region long before modern ecosystems developed.
Why the discovery matters
The research highlights how little scientists still know about Earth’s deepest ecosystems. Even after decades of ocean exploration, large areas of the seafloor remain poorly documented.
The new biodiversity information could also help scientists and conservation authorities better understand and manage Australia’s remote marine parks. Researchers say establishing a baseline of species and habitats is particularly important as deep-ocean environments face increasing pressure from warming oceans, pollution, fishing activity and potential deep-sea mining.
The scientists expect that their work is far from finished. Hundreds of collected specimens still require detailed taxonomic analysis, meaning additional species discoveries could emerge from the material gathered during the expeditions.
The latest findings therefore offer more than a list of new animals. They provide a rare glimpse into an immense underwater ecosystem and demonstrate that the deep Indian Ocean still contains major biological discoveries waiting to be made.
