Scientists have discovered two new species of sea spiders along the Canadian coastline, and they look nothing like the spiders you keep finding in your bedroom. The creatures, part of a family of marine arthropods called Pycnogonida, were found in the Salish Sea between Washington State and British Columbia. It is the first time sea spiders have been documented in that region in over a century.
The new species measure about a centimeter across. They were collected between September 2023 and August 2024 off the islands of Vancouver and Quadra in British Columbia. Cormac Toler-Scott, lead researcher on the team at the University of British Columbia, told NPR that while sea spiders share a name with land spiders, they never made the transition to dry ground.
“They never made that transition to land,” Toler-Scott said. “They really need to be in the water. They’re quite slow moving. They just kind of crawl on the seafloor.”
What Makes a Sea Spider
Sea spiders are marine arthropods that belong to a class called Pycnogonida. Scientists have discovered more than 1,300 species of them worldwide. The two new additions join that existing catalog.
Toler-Scott described the differences between land spiders and sea spiders clearly. Land spiders can walk across your living room floor. Sea spiders can barely move at all.
“They’re very clean and not all sea spiders can do this,” he said.
The Two New Species
The first new species is called Callipallene pilosuspedes. It has red eyes, a three-lipped mouth shaped like a triangle, and a curved spine covering its legs. Its limbs come from its belly and are called ovigers. These limbs can be used to groom itself and comb off dirt as well as algae.
The second species is named Tanystylum kiixin. It takes its name from an ancient Indigenous village near where it was found. It has shorter, stockier legs coming out of its chest. Unlike Callipallene, these legs cannot be used to clean the spider.
“It’s everyone’s kind of dream to find new species, but it’s pretty uncommon,” said Toler-Scott. “It’s hard to get funding for this kind of work because you go into it not really knowing what you’re going to get.”
How They Eat
Sea spiders don’t spin webs and wait for prey to stumble in. They feed on living animals, specifically a marine animal that looks like a plant and lives in colonies. Those animals are called hydroids. The sea spiders attach themselves to the hydroids and feed on them like parasites.
“They’re both living on that and feeding on that, kind of walking through it like a maze, and they just kind of poke a hole into the hydroid itself, and then they suck the juices out of it, like the cells out of the hydroid. That’s how they get their food,” Toler-Scott explained.
Mating and Camouflage
Sea spiders reproduce in a way that sets them apart from land spiders. Females develop the eggs, but males take over the responsibility for caring for them until they hatch. Many sea spiders, including the newly discovered ones, are transparent and take on the color of whatever they have eaten. They also use camouflage to avoid being eaten, since they lack venom or fangs.
Why Finding Them Matters
Discovering new species is rare. Toler-Scott put it plainly: “It’s everyone’s kind of dream to find new species, but it’s pretty uncommon.” Funding for this kind of work is hard to secure because researchers often go into it without knowing what they will find.
“With additional dives planned, the British Columbia researchers expect to find more species of sea spiders in the future,” the announcement concluded.
What Comes Next
The researchers plan more dives in the Salish Sea. The announcement did not specify a timeline beyond that.
For now, the two new species stand as a reminder that the ocean still holds secrets. Even in a well-studied region like the Salish Sea, a century can pass between records of a group of animals. These sea spiders may be small, but their discovery is a big deal for marine biology.
The fact that they were found at all is remarkable. That they were found in a region where none had been recorded in over a century is extraordinary. And that they have such unusual features — grooming limbs, a three-lipped mouth, red eyes — makes them particularly charming.
The research team at the University of British Columbia worked through the challenges of a field where success is not guaranteed. Finding new species is a difficult task, and the funding challenges Toler-Scott mentioned are real. Yet the team persevered, and the results are two new additions to the catalog of life on Earth.
The announcement of these two new species is a reminder that science is not finished. There is always more to learn, more to see, more to document. The Salish Sea has given us two new names, and the researchers behind the project have given us a reason to care about the tiny creatures that call it home.
The future dives planned by the team promise more answers. The Salish Sea may hold more sea spiders waiting to be named. For now, Callipallene pilosuspedes and Tanystylum kiixin are the stars of the show.
Source material: “Scientists discover two new species of sea spiders along Canadian coastline,” NPR.
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