If you thought land spiders were intimidating, wait until you meet their ancient, ocean-dwelling relatives.
For the first time in nearly a century, scientists have formally identified two new species of sea spider in the Salish Sea—the coastal waterway spanning southwestern British Columbia and northwestern Washington State.
Led by researchers at the University of British Columbia (UBC) and published in Organisms Diversity & Evolution, the study reveals that the Pacific Northwest’s waters are hiding some genuinely uncanny creatures.
What Exactly Are Sea Spiders?
Despite their name and leggy appearance, sea spiders (Pycnogonida) are not true arachnids. They belong to an ancient marine lineage that branched off roughly 500 million years ago, making them distant relatives of modern spiders, scorpions, and horseshoe crabs.
These marine invertebrates survive in marine habitats worldwide—from intertidal shallows to deep Antarctic waters—and exhibit bizarre traits:
- No lungs or gills: They absorb oxygen directly through their skin.
- Limbs with ovaries: Female sea spiders develop eggs inside their legs because their central bodies are too small to house internal organs.
- Single dad duties: Males carry and care for the eggs, gluing clusters of egg sacs to specialized head appendages called ovigers.
- Juice-sucking mouthparts: Many shallow-water species live as parasites on larger organisms, using a straw-like proboscis to suck fluids from their hosts.
Meet the New Species
Between late 2023 and mid-2024, UBC researcher Cormac Toler-Scott and his team conducted diving expeditions down to 18 meters around Quadra Island, Vancouver, Bamfield, and Victoria.
Using microscopic analysis combined with DNA sequencing, they cataloged two previously unknown species.
1. Callipallene pilosuspedes (The Hairy-Footed Groomer)
- The Name: Latin for "hairy feet," named after the long, curved spines covering its lower legs.
- The Look: Features striking red eyes and a triangular, three-lipped mouth surrounded by sensory tendrils—resembling a microscopic sea monster.
- Unique Trait: Under the microscope, scientists observed this species wrapping its flexible egg-carrying limbs (ovigers) around its legs to comb and groom its own body.
2. Tanystylum kiixin (The Walking Ecosystem)
- The Name: Named in honor of Kiixin (pronounced kee-hin), an ancient Indigenous village site near where specimens were found.
- The Look: A compact, heavily textured sea spider with short, rigid limbs.
- Unique Trait: Lacking the flexible grooming appendages of C. pilosuspedes, T. kiixin frequently gets covered in marine debris and tiny hitchhiking parasites—effectively creating a tiny "ecosystem within an ecosystem."
Why This Discovery Matters
Marine invertebrates in the Salish Sea face increasing threats from climate change, ocean acidification, and habitat disruption. However, protecting these species requires knowing what exists in the first place.
"In order to understand how marine invertebrates are being impacted by things like climate change and how we can better protect these key elements of the ecosystem, we have to be able to identify them."
— Cormac Toler-Scott, lead author and UBC Zoology researcher
Prior to this study, genetic data for Salish Sea sea spiders was almost non-existent. By generating the first DNA sequences for several local species and creating a comprehensive identification guide, the UBC team has laid the groundwork for future conservation efforts.
And according to the researchers, this is just the beginning—many more undiscovered creatures likely remain hidden beneath the surface.
