Research · Two New Sea Spider Species Discovered in the Salish Sea

Research · Two New Sea Spider Species Surface in the Salish Sea

A master's student's scuba fieldwork along the Pacific Northwest coast has turned up two species of sea spider new to science — one with ruby eyes and hairy legs, the other a "swamp monster" so unkempt it carries its own parasites.

Researchers at the University of British Columbia, led by evolutionary biologist Cormac Toler-Scott, collected more than 150 sea spiders during dives around Quadra Island, Vancouver, Bamfield and Victoria between September 2023 and August 2024. Morphology plus DNA barcoding showed the haul represented five shallow-water species — two of them undescribed, reported August 26 in the journal *Organisms Diversity & Evolution*.

The showier find, *Callipallene pilosuspedes* ("hairy feet"), is a third of an inch across with glowing red eyes, a claw-armed feeding tube (proboscis) and a three-lipped mouth fringed with sensory tendrils. The other, *Tanystylum kiixin* (pronounced "kee-hin"), is named for the ancient Indigenous village site where the first specimens were found; its underdeveloped egg-carrying limbs mean it cannot groom itself, so the 82 individuals collected were often crusted with debris and tiny parasites — "an ecosystem within an ecosystem within an ecosystem."

Sea spiders are a strange lineage: they evolved roughly 500 million years ago, are related to land spiders, scorpions and horseshoe crabs, and have lost their abdomens entirely — they breathe, reproduce and digest with organs housed in their legs. Only about 1,400 ocean species are documented, against 50,000 land spiders.

The takeaway the researchers stress: these came from the Salish Sea, one of the best-studied stretches of coastline on Earth. "If a master's student can find two new species of sea spiders in one field season of scuba diving along the coast of British Columbia, imagine how many undescribed species of marine invertebrates need to be documented before anthropogenic disturbance and climate change completely alter these marine communities forever."

- Source: Smithsonian Magazine