Night-swimming in the Salish Sea, you might feel something crawling up your leg—a tiny creature with dense bristly legs, red eyes, and a mouth split into three parts like a miniature Sarlacc pit from Star Wars. Don't worry: most sea spiders are under a centimeter long and live on the seafloor, feeding on prey even smaller than themselves—or simply piercing victims and sucking out their fluids.
In September 2026, researchers at the University of British Columbia (UBC) published two new sea spider species in *Organisms Diversity & Evolution*—the first new sea spider species formally described from the Salish Sea in nearly a century.
One Clean, One Dirty
The first species, Callipallene pilosuspedes (Latin for "hairy feet"), has red eyes, a short proboscis with claws for grabbing food, and a triangular mouth surrounded by sensory tentacles. Its most remarkable feature is a pair of extremely flexible ovigers—appendages at the base of the head that it can wrap around its own legs, using comb-like spines to clean its body. It's the neat freak of the sea spider world.
The second species, Tanystylum kiixin—named after an ancient Indigenous village site, for the sound of waves striking the reef below the village—has much smaller, less flexible ovigers and cannot groom itself. Researchers found it covered in dirt, debris, and crawling with tiny parasites.
UBC master's student Cormac Toler-Scott, the paper's first author, summed it up: "It's an ecosystem within an ecosystem within an ecosystem." This nesting of parasites upon parasites is called hyperparasitism—not rare in nature, but extraordinary to see on a sea spider only a few millimeters long.
425 Million Years of Strange Survival Strategies
Sea spiders (Pycnogonida) are an extremely ancient group, with fossils dating back at least 425 million years. Distant relatives of scorpions, spiders, and horseshoe crabs, they never left the ocean.
Around 1,400 species are known, with leg counts ranging from 4 to 12, and sizes from under a centimeter to 70 centimeters across (in Antarctic waters). They have no gills and no lungs—they breathe through their skin, with oxygen diffusing directly through pores in the body surface. Their secret is surface-area-to-volume ratio: long, thin legs make the animal essentially a living gas-exchange membrane. Antarctic giant sea spiders grow so large partly because cold polar water is oxygen-rich.
Their reproduction is equally counterintuitive: males carry the young. During mating, males use their ovigers to catch eggs, coat them in mucus, and glue them onto their own bodies in clumps until hatching. Sea spiders have been full-time dads for hundreds of millions of years.
Notably, the ovigers that keep *C. pilosuspedes* clean originally evolved for carrying eggs—the same appendages serve as both pouch and comb, a classic case of evolutionary repurposing.
Why Did We Only Find Out Now?
The Salish Sea, tucked between Vancouver Island and the mainland near Vancouver and Seattle, is one of the most intensively studied marine regions on Earth—yet no new sea spider species had been described there in almost a hundred years.
Toler-Scott's explanation is direct: "I wanted to study how sea spiders are affected by climate change and human activity, but I couldn't find anything—because we simply don't know what species live here or how."
Between September 2023 and August 2024, he dove to depths of 18 meters at sites including Quadra Island, Vancouver, Bamfield, and Victoria to collect samples. Combining detailed imaging with DNA analysis, he described the two new species, generated genetic data for several never-before-sequenced species, and produced an identification guide for Salish Sea sea spiders.
"I only did one field season, but there's certainly more diversity there we haven't recorded."
Two Species, Two Fates
The two species lead very different lives. C. pilosuspedes is a "refined" specialist—rare (only one specimen found), clean, and self-sufficient. T. kiixin is a "free-range" generalist—common (multiple specimens), dirty, and heavily parasitized, but apparently doing just fine.
This raises an evolutionary question: is being "clean" actually good? Energy invested in self-cleaning may come at a cost elsewhere. Perhaps outsourcing cleaning to the ecosystem—letting parasitic relationships reach their own equilibrium—is a viable, even economical, strategy in the Salish Sea. That nested ecosystem sounds frightening, but it may be exactly how *T. kiixin* survives: not war, but negotiation.
What Sea Spiders Teach Us
- Unknown does not mean nonexistent. Even one of the world's most studied seas hid new species for a century—not because they weren't there, but because nobody looked. Our confidence in "the known" is often just a byproduct of nobody searching.
- Weirdness is not a defect—it's a strategy. Skin breathing, paternal egg-carrying, drinking prey through straws: every one looks like an evolutionary oddball choice, yet after 425 million years, they're still here. In a system that runs long enough, its "weirdness" is its competitive advantage.
- Nesting is the norm, not the exception. Our guts hold bacteria, bacteria hold phages. Every one of us is a walking multi-layered ecosystem—sea spiders simply make it visible.
It sounds plain, but the lesson runs deep: you cannot protect what you don't recognize. In ecology, in AI, in any complex system, "seeing" is always the first step—and the method of seeing (DNA sequencing plus microscopy, not a diver's naked eye) determines what can be seen.
Next time you're at the seaside, consider the tiny red-eyed, three-lipped, hairy-legged creature crawling slowly on the seafloor, carrying its eggs—and its parasites, which carry parasites of their own. It has lived this way for 400 million years. It doesn't know you, but your future may partly depend on whether you can come to know it.
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*Reference: Toler-Scott, C. et al. (2026). "Two new species of sea spiders from the Salish Sea." Organisms Diversity & Evolution. DOI: 10.1007/s13127-026-00707-3*