Two new species of sea spiders, Tanystylum kiixin and Callipallene pilosuspedes, have been identified in the shallow waters of the Salish Sea and off Vancouver Island, representing the first new pycnogonid descriptions in the region in nearly a hundred years. The discovery, published in Organisms Diversity & Evolution on August 26, 2026, resulted from a year-long study led by Cormac Toler-Scott, a graduate student at the University of British Columbia (UBC). One of the new species was first sighted two decades ago but remained unnamed until this formal taxonomic classification.
What are sea spiders and how do they differ from land spiders?
Sea spiders, or Pycnogonida, are marine arthropods that are not true spiders, despite their name and appearance. While they share a common ancestor with scorpions, spiders, and horseshoe crabs, they diverged from that lineage approximately 500 million years ago during the Cambrian period. These creatures possess unique physiological traits: they have no gills and absorb oxygen directly through their skin. Their vital organs, including the ovaries in females, are often housed within their legs due to their extremely thin bodies. In a reversal of common roles, the males are responsible for parental care; they use specialized appendages called ovigers to collect eggs from the female, cement them to their own bodies using a self-produced adhesive, and carry them until they hatch.
Pycnogonids vary wildly in size, with leg spans ranging from a single millimeter in warm coastal waters to 50 centimeters in the deep, cold currents of the poles. Most coastal species are parasites or predators of larger invertebrates, using a proboscis to pierce their prey and suck out fluids. To date, 1,392 species have been identified globally.
Why was the Salish Sea's sea spider population largely unmapped?
The Salish Sea is a vast inland waterway shared by Canada and the United States, home to over nine million people and some of Canada’s most endangered marine life, yet its sea spider populations remained under-researched for decades. Prior to this study, only 17 species of shallow-water sea spiders had been reliably recorded in the region. Researchers believe this low number was a reflection of a lack of focused study rather than a lack of biological diversity. Between September 2023 and August 2024, the UBC team collected samples from tide pools down to depths of 18 meters around Quadra Island, Vancouver, Bamfield, and Victoria. Using scanning electron microscopy and DNA sequencing, they produced the first genetic data for five known species and identified the two new ones.
What are the characteristics of the newly named Callipallene pilosuspedes?
Callipallene pilosuspedes is distinguished by the long, curved spines covering the terminal segments of its walking legs, a feature reflected in its name (Latin for "hairy feet"). This species features distinctive red eyes and a short proboscis equipped with pincers for gripping food. Its triangular mouth is surrounded by three lips and sensory bristles, a configuration that UBC researchers compared to a miniature version of the Sarlacc monster from Star Wars. During observations, researchers noted that the animal uses its ovigers like combs to clean its legs, though much about the species remains a mystery as only a single female specimen was collected from a hydroid colony near Bamfield at a depth of 10 meters.
Why did Tanystylum kiixin remain unnamed for twenty years?
Tanystylum kiixin was likely first documented in 2006 near Cape Beale, but because the initial researchers did not follow formal taxonomic rules for its description, the name they suggested was considered a nomen nudum, or a "naked name," with no scientific standing. The new name, kiixin (pronounced "kee-hin"), honors an ancient Indigenous village site near the collection area. This species is easily identified by its five-segmented palps that extend past the tip of its proboscis. Unlike its cleaner relative, T. kiixin has short, blunt ovigers and cannot groom itself, leading to the accumulation of debris and single-celled parasites on its body. This creates what Toler-Scott describes as an "ecosystem within an ecosystem within an ecosystem," where the spider parasitizes hydroids while being parasitized itself.
What does this discovery mean for future marine research in British Columbia?
The discovery of C. pilosuspedes and T. kiixin suggests that the coastal waters of British Columbia hold significantly more biodiversity than previously recorded. Alongside the descriptions, the researchers published a new identification key to help future scientists categorize sea spiders in the Salish Sea, an area where taxonomic confusion has been common for decades. Since this study only covered a single field season and depths up to 18 meters, researchers expect that more undiscovered species reside in deeper or less-explored areas of the coast. The type specimens for these new species are now housed at the Beaty Biodiversity Museum in Vancouver.
Notes and Sources
- Toler-Scott, C., Park, E., Gordon, H. & Leander, B. S. (2026). "Sea spiders of the Salish Sea: Comparative morphology and molecular phylogenetic analysis of seven coastal species (Arthropoda, Pycnogonida)." Organisms Diversity & Evolution, August 26, 2026. doi:10.1007/s13127-026-00707-3.
- Walls, A. (2026). "Hairy-legged red-eyed sea spiders discovered in the Salish Sea." University of British Columbia News, September 23, 2026.
