A University of British Columbia master’s student has formally described two new sea spider species collected from the Salish Sea, the first additions to the region’s sea spider list in nearly a century. One of them, a hairy-legged, red-eyed animal named Callipallene pilosuspedes, uses comb-like spines on its own legs to groom itself, a trick its plainer, dirt-caked neighbor cannot manage. Cormac Toler-Scott collected both animals from waters around Vancouver Island during a single season of research diving.
Two Species, One That Grooms and One That Cannot
Callipallene pilosuspedes takes its name from the Latin for hairy feet, a nod to the long, curved spines covering the lower portion of its legs. It has red eyes, a short proboscis tipped with grasping claws, and a triangular, three-lipped mouth ringed with sensory tendrils, and it is dexterous enough to use comb-like spines on its egg-carrying limbs, called ovigers, to groom dirt and hitchhiking parasites off its own body. Researchers found only a single specimen of the species during the entire study, so how common Callipallene pilosuspedes actually is in the Salish Sea remains unknown. Grooming matters more for a sea spider than it might for a larger animal: many pycnogonids live pressed against a host or buried in sediment, and clearing debris and parasites off exposed sensory tendrils and joints can be the difference between detecting a threat and missing one.
The second animal, Tanystylum kiixin, is named for Kiix̲in, an Indigenous village site near where it was found, and it has smaller, less flexible ovigers that leave it largely unable to clean itself. Researchers repeatedly found specimens of T. kiixin coated in dirt, debris and tiny parasites, a visible consequence of a body that cannot reach every part of itself the way its hairy-legged cousin can.
A Master’s Student’s Single Field Season
Toler-Scott, working with University of British Columbia zoologist Brian S. Leander and co-authors Eunji Park and Heather Gordon, collected both animals during dives to depths of up to 18 meters off Vancouver Island, near Quadra Island, Bamfield and Victoria, between September 2023 and August 2024. The team published its description in the journal Organisms Diversity & Evolution, with funding from Canada’s Natural Sciences and Engineering Research Council.
Toler-Scott said his interest started with a gap he could not explain: sea spiders are affected by climate change and human disturbance the same way other marine invertebrates are, and the Salish Sea’s invertebrates are considered particularly at risk, yet when he went looking for existing records on local sea spiders during his master’s degree, he found essentially nothing to work from. An absence of baseline data, rather than any single sighting, is what sent him into the water himself with a collecting jar.
The Century Since the Salish Sea’s Last New Sea Spider
Sea spiders, or pycnogonids, are marine arthropods unrelated to true spiders despite the name, with more than 1,300 known species worldwide ranging from roughly a millimeter to more than 70 centimeters in leg span. According to UBC, the two new finds mark the first sea spider species formally described from the Salish Sea in close to 100 years, even though the inland sea is bordered by two of the busiest urban coastlines in North America and its waters run through the Strait of Georgia, the Strait of Juan de Fuca and Puget Sound.
“That’s largely because people don’t know much about what species exist here and what their lifestyle is,” Toler-Scott said, describing why a body of water this heavily studied for salmon, orcas and shellfish had gone so long without a new sea spider on record. The Salish Sea borders Vancouver, Victoria, Seattle and Tacoma, among the most heavily monitored coastlines in North America for larger, commercially or culturally prominent species, which makes the century-long gap in its smallest arthropods more a matter of research priorities than of the animals being genuinely rare.
Small Invertebrates as a Measure of Coastal Health
Sea spiders live as parasites or scavengers on other invertebrates, piercing hosts with a proboscis to draw out fluids, and many shallow-water species stay small enough to escape casual notice even where they are common. Some species live so intimately with a host that Toler-Scott has described them, in general terms, as using a weird apparatus to suck the juices out of whatever larger animal they have attached themselves to. He said identifying species such as these matters beyond taxonomy, since tracking how climate change and human disturbance affect marine invertebrates, and protecting the ecosystem functions those animals perform, depends on being able to name them in the first place.
Toler-Scott collected both new species across a single field season and expects the true number of undocumented animals in the Salish Sea to be far higher than two. Plenty more diversity is out there, he has said, simply undocumented, a gap that another graduate student’s diving season could start to close.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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