Red-eyed, parasitic, hairy-legged sea spiders of the Salish Sea go under the microscope in Vancouver

An ocean-dwelling, hairy-legged, red eyed, parasitic sea spider sounds like the kind of monster that might pay you a visit during the throes of a very bad dream.

But these creepy-sounding creatures inhabit planet earth — in fact, researchers recently discovered two new species of them in southern B.C.’s Salish Sea.

“This region is really under-studied for a lot of marine invertebrates, but particularly sea spiders,” said the University of British Columbia’s Cormac Toller-Scott, who conducted the work as part of his master’s degree in zoology.

“They are related to terrestrial spiders, but they evolved long before terrestrial spiders… and never left the oceans.” 

He said only 20 species of sea spider had been documented in the Salish Sea and Vancouver Island region.

Between September 2023 and August 2024, Toller-Scott and a team of researchers conducted dives up to 18 metres deep in a range of marine habitats in the area, including at Quadra Island, Vancouver, Bamfield, and Victoria.

“We collected as many different species as we could… and we looked at really fine-detail characteristics of the body, and compared that to every other species of sea spider that has been described in the world,” Toller-Scott said.

“And then we also collected genetic data and we compared that genetic data with data from other species.”

Once they had examined the samples, the team realized that two of the collected species had never been documented before.

They were found on an underwater organism called a hydroid, described as being “like a jellyfish that is attached to the ground.”

“They never really leave it, they just walk around on it,” Toller-Scott said.

“They feed on it by eating little pieces of it with their proboscis. So you could consider them a parasite of that larger organism.”

One species was named Callipallene pilosuspedes, a play on Latin for “hairy feet”, after the fine spines covering its lower legs.

The other, Tanystylum kiixin, is named after an Indigenous village site near where specimens were collected.

Last year, a team of UBC researchers led by biologist Shana Goffredi discovered three new species of sea spider that live exclusively near methane seeps and hydrothermal vents on the ocean floor.

They demonstrated a remarkable ability to grow “monocultures” of bacteria that transformed methane, a greenhouse gas, into life-sustaining nutrients. 

Goffredi described the discovery as “a happy accident,” as she had initially set out to study methane seeps.  

Toller-Scott said taxonomic research projects like his sea-spider one tended not to receive much funding, despite playing a crucial role in scientific advancements.

“Taxonomy is really important for understanding the foundation of a place, so that you can ask bigger questions,” he said.

“There are many new species out there waiting to be found, especially along the West Coast of Canada, which is one of the most diverse coastlines in the world.”