Researchers exploring the Salish Sea off the Pacific coast of British Columbia have discovered two new sea spider species, including one featuring hairy lower legs and red eyes, and another hosting an intricate community of parasites. The finds mark the first description of new sea-spider species from the region in nearly a century.
Diving beneath the surface of the inland waters nestled between British Columbia and Washington state, University of British Columbia zoology master’s student Cormac Toler-Scott uncovered two previously unknown marine arthropods. Collected during scuba dives reaching depths of up to 18 meters between September 2023 and August 2024, the specimens represent a rare formal documentation of a poorly understood group of animals in the region. The findings were detailed in a study published in the journal Organisms Diversity & Evolution.
Callipallene pilosuspedes and Its Hairy Limbs
The first of the newly identified species has been named Callipallene pilosuspedes, a designation drawing from Latin terms for hairy feet. According to university researchers, the creature sports striking red eyes and a short proboscis outfitted with claws to grasp food before biting. Its triangular, three-lipped mouth is surrounded by sensory tendrils.
Under microscopic examination, the sole specimen recovered of this species revealed highly flexible egg-carrying limbs known as ovigers. While males typically use these appendages to carry fertilized eggs until hatching, the study’s lead researcher observed the animal wrapping the structures around its legs and using attached comb-like spines to clean itself.
Tanystylum kiixin and Its Parasitic Burden
In contrast, the second new species—named Tanystylum kiixin—presents a completely different set of physical traits and ecological pressures. Researchers named the species after the ancient Indigenous village site of Kiixin, where specimens were first collected, deriving the name from the sound of waves crashing at the base of the site.
Unlike its hairy-legged counterpart, Tanystylum kiixin features much smaller and less dexterous ovigers, leaving the animal unable to groom itself effectively. Microscopic analysis frequently revealed the creatures covered with tiny protist parasites of their own. That reality prompted the research team to characterize the discovery as an ecosystem within an ecosystem within an ecosystem,
linking the parasites living on a sea spider that itself forms a part of the broader marine web.
Deciphering Ancient Marine Arthropods
Sea spiders, or pycnogonids, are marine arthropods that trace their evolutionary origins back approximately 500 million years. While they share distant ancestry with land-dwelling scorpions, spiders, and horseshoe crabs, these creatures remained aquatic, breathing through their skin and utilizing specialized proboscises to suck juices from hosts.
Salish Sea invertebrates have historically remained poorly documented, creating significant gaps in understanding how these shallow-water organisms respond to environmental pressures. The research team combined detailed imaging with DNA analysis across multiple sampling sites—including Vancouver, Victoria, Quadra Island, and Bamfield—to generate genetic data for several species that had never been sequenced before.
Conservation Stakes Along a Developed Coastline
Researchers emphasize that cataloging local biodiversity is a critical prerequisite for understanding how marine ecosystems respond to climate change and human disturbance. Without clear baseline data on which species inhabit these waters and what their specific lifestyles entail, determining where protective interventions will have the greatest impact remains difficult.
Having registered the new species in a global taxonomic database and compiled a regional identification guide for future scientific expeditions, the team believes further hidden diversity remains waiting to be discovered across the Pacific Northwest.
