Researchers exploring the Salish Sea in the Pacific Northwest have discovered two previously unknown species of sea spiders, including one specimen featuring red eyes, hairy legs, and a three-lipped mouth, according to a study published in the journal Organisms Diversity & Evolution. University of British Columbia zoology master’s student Cormac Toler-Scott led the fieldwork, utilizing scuba diving to collect specimens between September 2023 and August 2024. The findings highlight how targeted sampling in inland waters can yield entirely new marine invertebrates even as climate change threatens coastal ecosystems.
Salish Sea Fieldwork Yields New Pycnogonid Species
Marine biologists describe sea spiders—known scientifically as pycnogonids—as ancient arthropods belonging to the chelicerate branch of life. Emerging roughly 500 million years ago before modern true spiders evolved, these animals adapted to marine environments alongside their horseshoe crab cousins. Discovering new pycnogonid species remains rare because the animals are typically tiny, cryptic, and visually similar, compounded by a small global pool of active researchers.
During his field season along the coast of British Columbia and Washington, Toler-Scott identified seven distinct sea spider species using microscopy and genetic sequencing. Among them are two species never previously categorized by science.
The Hairy Feet Sea Spider and Its Unique Morphology
Researchers named the first newly described species Callipallene pilosuspedes, translating roughly to "hairy feet" in Latin. This organism features red eyes, a short proboscis equipped with claws for holding prey, and a triangle-shaped mouth covered in tendrils.
Under laboratory microscopy, the team observed a single C. pilosuspedes specimen utilizing its ovigers—appendages typically used by males to carry fertilized eggs—to groom itself. The UBC press release compared the creature’s three-lipped mouth to a "tiny marine Sarlacc pit."
Parasitic Pressures on Tanystylum kiixin
The second newly discovered species received the name Tanystylum kiixin, honoring the ancient Indigenous village site near the initial collection area. Pronounced "kee-hin," the name reflects the sound of waves breaking at the base of the village site.
While sea spiders frequently act as parasites on larger marine animals in shallow waters, the research team observed their own surprise finding: tinier protist parasites living directly on the T. kiixin specimen. Unlike C. pilosuspedes, T. kiixin possesses smaller ovigers, leaving it less capable of grooming away these unwanted freeloaders.
"If a Masters student can find two new species of sea spider in one field season of SCUBA diving along the coast of BC, imagine how many undescribed species of marine invertebrates need to be documented before anthropogenic disturbance and climate change completely alter these marine communities forever," Cormac Toler-Scott said via Gizmodo.
FAQ About Sea Spider Discoveries
What are sea spiders?
Sea spiders are marine arthropods called pycnogonids that belong to the chelicerate branch of life, making them distant relatives of land spiders and horseshoe crabs.
Where were the new sea spider species found?
Researchers found Callipallene pilosuspedes and Tanystylum kiixin in the Salish Sea, an inland body of water nestled between British Columbia and Washington state.
Why are new sea spider species hard to find?
Pycnogonids are typically tiny, cryptic, and visually similar to one another, and relatively few scientists worldwide actively study them.
How do sea spiders interact with parasites?
Sea spiders can act as parasites on larger marine animals, but they can also host smaller parasites on their own bodies, such as the protists found on Tanystylum kiixin.
Did You Know?
Giant sea spiders living in the deep ocean are sometimes used as living taxis by other arthropods, according to a separate research team.
Pro Tip for Marine Researchers
Targeted scuba diving in shallow coastal areas remains an effective method for discovering undescribed invertebrate species, as demonstrated during the recent Salish Sea surveys.
What other hidden species might be waiting in the Salish Sea? Share your thoughts in the comments below, explore our related marine biology articles, and subscribe to our newsletter for the latest science discoveries.
Worth a look