In the cold, layered waters of the Salish Sea, two creatures have existed for untold ages without a name in science's ledger — until now. UBC researcher Cormac Toler-Scott, diving off Vancouver and Vancouver Island, identified two previously unknown sea spider species, Callipallene pilosuspedes and Tanystylum kiixin, bringing the documented regional count to twenty. Their discovery is less a triumph of finding something new than a reminder of how much the familiar ocean still conceals, and why naming what lives among us is the first act of stewardship.
UBC researchers discover two new sea spider species in Salish Sea
More diversity out there that we haven't documented
Mark
So these are actual spiders that live underwater?
Mimi
Not quite. They're related to spiders—same family tree as scorpions and horseshoe crabs—but they're not true arachnids. They breathe through their skin, which is completely different from how land spiders work.
Luke
And we're sure these are genuinely new to science? Not just new to this region?
Mimi
Yes, completely new species. The paper was published this summer. Toler-Scott's team formally documented them.
Mark
What makes them so hard to find if they're living right here in the Salish Sea?
Mimi
They're tiny—about a centimetre across. And honestly, sea spiders just haven't been studied much in this region. Nobody was really looking for them systematically.
Luke
How many sea spider species are actually in the Salish Sea? Is twenty the total, or is that just what's been documented?
Mimi
Twenty is what's been documented. Toler-Scott is pretty clear that there's much more diversity out there. He had one field season and already found two new species.
Mark
Why does it matter that we know what sea spiders are here?
Mimi
Toler-Scott wants to understand how they're affected by climate change and human disturbance. But you can't study that if you don't even know what species exist or how they live.
Luke
So this is really a baseline study—establishing what's here before we can ask bigger questions about their health?
Mimi
Exactly. It's foundational work. The discovery itself is the story, but the real story is how much we don't know about marine invertebrates in local waters.
Mark
The males carry the eggs on their bodies?
Mimi
Yes, they glue them on using secretions from their legs. It's one of those details that makes you realize how strange life underwater can be.
Luke
And the second species gets parasites because its egg-carrying limbs don't work as well?
Mimi
That's what the research shows. Evolution hasn't optimized that feature the same way it did for the first species.
The Pulse
- Two centimetre-wide sea spiders, invisible to science until this summer, have been formally named and entered into the scientific record after a single UBC field season.
- The find exposes a striking gap: even in a heavily studied coastal region like the Salish Sea, basic marine invertebrate diversity remains poorly mapped and largely unknown.
- Sea spiders themselves defy easy categorization — breathing through their skin, with males carrying eggs glued to their own bodies, they are among the ocean's most biologically unusual arthropods.
- One of the new species, Tanystylum kiixin, is already under pressure: its less effective egg-carrying limbs leave it vulnerable to parasites that exploit that weakness.
- Toler-Scott warns that twenty documented species is almost certainly a fraction of what exists, and that meaningful climate and disturbance research cannot proceed without first knowing who actually lives in these waters.
In the cold, layered waters of the Salish Sea, two creatures have existed for untold ages without a name in science's ledger — until now. UBC researcher Cormac Toler-Scott, diving off Vancouver and Vancouver Island, identified two previously unknown sea spider species, Callipallene pilosuspedes and Tanystylum kiixin, bringing the documented regional count to twenty. Their discovery is less a triumph of finding something new than a reminder of how much the familiar ocean still conceals, and why naming what lives among us is the first act of stewardship.
Cormac Toler-Scott was diving off Vancouver and Vancouver Island when his research team collected two creatures science had never formally recorded: sea spiders now named Callipallene pilosuspedes and Tanystylum kiixin. The UBC master's student led the work that produced a published paper this summer, quietly expanding the Salish Sea's documented sea spider count to twenty species.
Sea spiders sit in a strange corner of the arthropod family tree — related to land spiders and horseshoe crabs, yet not arachnids. They breathe through their skin, and it is the males who carry and tend the eggs, gluing them to their own bodies using secretions produced in their legs.
Callipallene pilosuspedes is translucent white with red eyes, a short clawed proboscis, and a triangular three-lipped mouth ringed by sensory tendrils. Tanystylum kiixin takes its name from an ancient Indigenous village on Vancouver Island; its egg-carrying head limbs are less capable than its cousin's, leaving it exposed to shell-like parasites with thread-like appendages.
Toler-Scott is candid about what the discovery really signals: a gap, not a conclusion. He entered this research hoping to study how sea spiders respond to climate change and human disturbance, only to find that no reliable species baseline existed. Finding two new species in one field season suggests many more remain undocumented, waiting in the depths for someone willing to look.
Cormac Toler-Scott was diving off the coast of Vancouver and Vancouver Island when he and his research team collected something science had never formally documented before: two entirely new species of sea spiders. The creatures, officially named Callipallene pilosuspedes and Tanystylum kiixin, measure roughly a centimetre across their leg span and represent a small but genuine expansion of our understanding of what lives in the Salish Sea. The UBC masters student led the work that resulted in a published paper this summer, adding these organisms to the scientific record.
Sea spiders occupy an unusual place in the arthropod family tree. They are related to land spiders, scorpions, and horseshoe crabs, yet they are not arachnids themselves. What makes them distinctly alien is their physiology: they breathe through their skin rather than through lungs or spiracles, and in a reversal of typical animal reproduction, the males are the ones who rear the young. The males possess specialized limbs at the base of their heads—a feature that serves a peculiar purpose. They use these appendages to carry and manage eggs, gluing them to their own bodies using secretions produced in their legs, then tending to them as they develop.
Callipallene pilosuspedes, the first of the two new species, presents a striking appearance. Its body is translucent white, punctuated by red eyes that give it an unsettling gaze. A short proboscis—essentially a nose-like structure—extends from its head, tipped with claws designed to grasp and manipulate food. Behind this apparatus sits a triangular mouth with three distinct lips, surrounded by sensory tendrils that function like tiny tactile whiskers. The second species, Tanystylum kiixin, takes its name from an ancient Indigenous village on Vancouver Island. It too possesses head limbs for egg management, though these appendages prove less effective than those of its cousin. This inadequacy leaves the species vulnerable to parasites that resemble miniature turtle shells with thread-like appendages dangling from their bases.
What Toler-Scott discovered during his field work hints at a much larger gap in marine science. Including these two new additions, researchers have now documented twenty distinct sea spider species in the Salish Sea and the waters off the west coast of Vancouver Island. Yet Toler-Scott emphasizes that this number represents only a fraction of what actually exists in these waters. "I only had one field season but there's definitely more diversity out there that we haven't documented," he told Vancouver Is Awesome. The reason for this knowledge gap is straightforward: sea spiders have received minimal scientific attention in the region, and their basic ecology remains poorly understood.
Toler-Scott's interest in these creatures stems from a broader concern about marine health. He wanted to investigate how sea spiders respond to climate change and human disturbance, recognizing that marine invertebrates in the Salish Sea face particular vulnerability. But he quickly realized that such research was impossible without first establishing a baseline of what species actually inhabit these waters and how they live. "That's largely because people don't know much about what species exist here and what their lifestyle is," he explained. The discovery of two new species in a single field season suggests that many more remain unknown, waiting in the depths for the next researcher willing to dive down and look.
Notable Quotes
The two new species are about a centimetre in legspan and are completely new to science, but were collected here in the Salish Sea.— Cormac Toler-Scott, UBC researcher
I only had one field season but there's definitely more diversity out there that we haven't documented.— Cormac Toler-Scott
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