Dozens of deep-sea species discovered as new crustaceans named

In the middle of the Pacific Ocean, one of the least-known environments on Earth is revealing its hidden diversity.

The Clarion-Clipperton Zone (CCZ) is a vast area covering around six million square kilometres of deep ocean between Hawaii and the west coast of Mexico. Despite its remoteness, the area has drawn a lot of interest recently because of the metallic nodules that litter the ocean floor.

These nodules contain minerals crucial to green energy technologies, such as solar panels and wind turbines, so mining them could help us hit the world’s net zero goals. However, as the deep sea is so poorly understood, there are concerns that important ecosystems might be damaged in the process.

As a result, researchers are hurriedly working to understand more about the CCZ’s animals, with 24 new species of deep-sea crustaceans known as amphipods the latest to be discovered. Their names have a variety of inspirations, from legendary monsters to a character from the popular video game Hollow Knight.

Dr Eva Stewart, one of our deep-sea scientists who helped to name some of the new species, says that they’re just a hint of what’s yet to come from the CCZ.

“It’s estimated there are around 5,600 species in the CCZ, but around 90% of these are undescribed,” explains Eva. “As a result, there are thousands of potential species that have been discovered over the past decade just waiting to be named.”

“Unfortunately, that backlog is building up because there are only a few scientists with the skills and knowledge to be able to work through them all. This taxonomy will be vital to consider the impact of possible deep-sea mining in the future, so collaborative projects like this, which include training for students, are really important to speed up the description of these species.”

The species were named in a special issue of the journal Zookeys.

What are amphipods?

Amphipods are an incredibly diverse group of crustaceans, with more than 10,000 known species. Some are just millimetres in size, while the biggest species can be longer than a small dog!

These crustaceans have adapted to a range of different environments, from species that live in dark, damp caves to landhoppers that live in woodlands and feed on leaf litter. However, the majority make their home in fresh and saltwater environments.

There are parasitic whale lice that ride around on marine mammals, grazing species that keep algae under control and predatory amphipods that hunt small worms and other invertebrates. Many other species are scavengers, playing a vital role in recycling nutrients to power marine ecosystems.

The aquatic amphipods we’ve discovered so far are incredibly diverse, but there are likely to be many more species hidden in the depths of the ocean. Just 13 species are currently known from the CCZ, but genetic and molecular samples suggest that there are probably more than 200 spread across the region.

The new species were found while Eva and other researchers were taking box cores from the seafloor. This is exactly what it sounds like – scientists extract a huge cube of mud from the seabed and bring it up to a ship so its contents can be studied.

After washing and sieving the cores, the scientists were delighted to find a variety of pale amphipods among the mud and nodules. These animals were a mixture of shapes and sizes, from those with long and spindly legs to others with more compact bodies.

“These amphipods appear to have a range of different feeding styles,” Eva adds. “Some seem to be eating the mud and getting nutrients from that, while others have large claws, which suggest they might be predating other things that are living in the sediment.”

“As we study them further, we hope to get a better idea of how these animals are living.”

Amphipod inspiration

Once the amphipods were collected, they were deposited in museums around the world, including at our own site in South Kensington. The scientists then met up for a week-long workshop at the University of Lodz in Poland to get through the difficult process of naming these species.

“Our aim was to describe as many species as we could in a week, which isn’t easy,” recalls Eva. “But it was a really collaborative atmosphere and by working together we managed to do a lot more than we would’ve done alone.”

“It was also great that, out of the 16 scientists in the room, 14 of us were women. That’s really uncommon in what’s traditionally been a very male-dominated field.”

In naming the species, the researchers drew on a diverse range of inspirations. Some species, such as Mirabestia maisie and Astyra mclaughlinae, got their names from family members and colleagues. Meanwhile, Elimedon breviclunis was named to reflect its distinctive short rump.

Others were inspired by pop culture, such as Lepidepecreum myla. This species reminded the scientists of Myla from the video game Hollow Knight, as both “are just little arthropods trying to survive in total darkness”.

Aside from new species, the team were also to name higher levels of the tree of life, including a family and superfamily. Dr Tammy Horton, one of the co-leads of the research, explains that such discoveries are “incredibly exciting”.

“To find a new superfamily is very rare, so this is a discovery we’ll all remember,” says Tammy. “But each species we describe is just as important, as they’re a vital step towards improving our understanding of this fascinating ecosystem.”

Species by species, this research is transforming the CCZ from a remote, poorly understood plain into a diverse environment filled with life. As more animals are named, we’ll get a much better idea of just what life in the deep ocean is like.