Researchers surveying the Salish Sea between September 2023 and August 2024 discovered two previously undescribed sea spider species, marking the first new regional discoveries in nearly a century. The findings help close a long-standing knowledge gap regarding marine invertebrates vulnerable to environmental alterations.
Researchers Discover Two Species
Marine scientists diving down to 18 meters, or about 59 feet, around Quadra Island, Vancouver, Bamfield, and Victoria uncovered two distinct sea spider species during field collections between September 2023 and August 2024. These creatures belong to an ancient lineage of marine arthropods that split off roughly 500 million years ago, sharing distant ties with scorpions, horseshoe crabs, and land spiders while remaining strictly aquatic.
Before these finds, researchers faced a severe lack of baseline data for regional invertebrate populations. I was interested in how sea spiders are impacted by climate change and human disturbance, because marine invertebrates in the Salish Sea are particularly at-risk, and I couldn’t find anything,
noted Cormac Toler-Scott, who spearheaded the study as part of his master’s degree in zoology at the University of British Columbia. Toler-Scott added that That’s largely because people don’t know much about what species exist here and what their lifestyle is.
Identifying these foundational elements of life along the Pacific Northwest coast remains a prerequisite for any meaningful conservation work.
Anatomy of Callipallene pilosuspedes and Tanystylum kiixin
The newly described specimens display unusual adaptations for survival and reproduction in cold Pacific waters. A short snout sits atop its head, featuring claws to grab food prior to feeding, which leads into a three-sided, triangular mouth surrounded by sensory projections that strikingly mirrors a tiny Sarlacc pit.
“They’ve retained some weird traits. A lot of the shallow water species are quite small, and so they’ll live as parasites on larger organisms, and they use this weird apparatus called a proboscis to suck the juices out of their host.”
Cormac Toler-Scott, University of British Columbia
How Sea Spiders Close a Century-Long Marine Biodiversity Gap
Beyond their feeding apparatus, sea spiders exhibit unusual internal and external biology. Yet, for one of the recently found Salish Sea types, those very same limbs responsible for carrying eggs functioned unexpectedly as grooming combs as well.
These discoveries, published in Organisms Diversity & Evolution, represent the first new sea spider species described in the Salish Sea in nearly a century, helping close a nearly century-long gap in regional marine biodiversity. Researchers emphasize that mapping local marine biodiversity is essential for tracking how human activity and shifting climate pressures alter fragile coastal ecosystems.
