A single expedition to a chain of underwater mountains in the Indian Ocean has yielded 149 species never before documented by science. The discovery, announced by researchers from Australia's Museums Victoria, doubles the known biodiversity of these remote seamounts and suggests the deep sea holds far more surprises than previously imagined.
A hidden menagerie beneath the waves
The team spent 45 days aboard the research vessel Investigator, surveying seamounts southwest of the Cocos (Keeling) Islands, an Australian territory. Using a deep-sea robot and trawling nets, they collected specimens from depths between 200 and 5,000 meters. Among the finds were 149 new species, including 60 arthropods, 40 sponges, 23 fish, 16 cnidarians (corals and anemones), and 10 echinoderms such as sea stars and sea cucumbers.
One striking example is a sponge crab from the genus Sphaerodromia, which carries a living sponge on its back as camouflage. Another is a bright red deep-sea anglerfish with a glowing lure. The researchers also found a sea urchin with long, needle-like spines and a carnivorous sponge that traps small crustaceans in its mesh-like body.
Why these underwater peaks matter
Seamounts are underwater mountains that rise from the ocean floor but do not reach the surface. They create nutrient-rich currents that attract a dense array of life, making them biodiversity hotspots. The seamounts surveyed are part of a protected marine park, but the area is also targeted by deep-sea fishing and potential mining operations. Local scientists and conservation groups in Australia have long pushed for better understanding of these habitats before any industrial activity expands.
The expedition was part of a broader effort to map and catalog life in Australia's remote Indian Ocean territories. The researchers used both physical collection and high-resolution video to document the creatures in their natural environment. Many of the new species are likely endemic, meaning they exist nowhere else on Earth.
The sheer number of new species found in a relatively small area underscores how little is known about the deep ocean. As the researchers continue to analyze their samples, they expect the total count to rise. This discovery not only expands the tree of life but also provides a baseline for future conservation decisions in a region facing growing human pressure.
