Two species of sea spider that scientists had never described before have been identified in the shallow waters of the Salish Sea, the body of water between Washington state and the Canadian province of British Columbia. According to the researchers who found them, they are the first new sea spiders recorded from those waters in more than 100 years, a gap that says as much about the limits of shore-based sampling as it does about the animals themselves.
The discovery was made by a team at the University of British Columbia, led by marine biologist Cormac Toler-Scott, who described the find to NPR in understated terms. The animals were not dramatic or dangerous; they were simply small, slow and abundant enough to go unnoticed by anyone who wasn't looking for them at the right depth.
The new species were collected between September 2023 and August 2024 from shallow waters off the British Columbia islands of Vancouver and Quadra. Both are roughly a centimeter across, about the width of a fingertip. That diminutive scale is a plausible explanation for the long gap in records: a creature an inch wide crawling on a dark seafloor is easy to overlook, particularly in waters that boaters, fishers and coastal residents pass over routinely.
One of the two species is *Tanystylum kiixin*, photographed by Cormac Toler-Scott for the University of British Columbia with a cluster of round eggs tucked inside its legs. The egg-bearing specimen offers a glimpse of the animal's full life cycle in the place it was collected, rather than a snapshot of an empty shell or an isolated individual drifting in a sample net.
The second species, *Callipallene pilosuspedes*, is described in more anatomical detail: red eyes, a three-lipped mouth shaped like a triangle, a curved spine that drapes over the legs, and a pair of limbs that emerge from the underside of the body. Those belly-born limbs, known as ovigers, are used for grooming and for combing debris away from the animal's surface. Features like eyes, mouthparts, spines and appendages are exactly the characters that taxonomists weigh when deciding whether a specimen is a new species or a familiar one in unusual clothing.
Sea spiders are marine arthropods belonging to a class called Pycnogonida. Scientists have identified more than 1,300 species of them, and the two Canadian finds add to that tally. Despite the name, they are not the aggressive, web-spinning spiders people picture when they hear the word; the resemblance to land spiders is real but misleading, and Toler-Scott was careful to explain the distinction.
"They never made that transition to land," Toler-Scott told NPR. "They really need to be in the water. They're quite slow moving. They just kind of crawl on the seafloor."
That statement captures why the find matters beyond the satisfaction of adding two names to the scientific record. Pycnogonids represent a lineage that stayed in the ocean, and their eight-legged, spider-like appearance is the kind of convergence in appearance that makes casual observers assume an animal is common or well known. The very traits that make sea spiders look familiar — a small body, a modest size, an unhurried crawl — are also the traits that let them slip through centuries of coastal collecting.
The century-long gap is the striking part of the story. The Salish Sea is among the most heavily used inland waters in the Pacific Northwest, crisscrossed by shipping lanes, aquaculture sites, fishing grounds and heavily developed shorelines. If two species survived there without being formally recognized until now, the reasonable inference is that other undescribed species may be present as well, and that the real census of this seafloor is nowhere near complete.
That has practical consequences. A species that has no name cannot be tracked, compared or protected; baseline records are what allow researchers to say whether a population is stable, shrinking or newly arriving. Naming the animals is the first step in building that baseline, and it gives agencies and conservation groups something concrete to reference in the Salish Sea, a transboundary water where monitoring data is often fragmented between two countries.
Carrying eggs, as the photographed *Tanystylum kiixin* was doing, also signals that these animals are not incidental visitors to the area but residents completing their life cycles in it. The collection window of nearly a year suggests researchers were sampling repeatedly rather than making a single sweep, which matters for animals whose reproduction and seasonal movements are only beginning to be documented.
The next stage of the work — formal description and publication — is what will allow the rest of the scientific community to verify the findings and reexamine specimens sitting unlabeled in older collections. It is also the point at which the broader survey question becomes answerable: how many other small, slow, ocean-bound animals are still waiting in the same shallow water, carrying round eggs and missing from the record?
For now, the reassuring framing from Toler-Scott holds. The animals that have generated international attention will not migrate into anyone's living room. They need water, they move at a crawl along the seafloor, and until recently, two of their number were essentially invisible in waters that people thought they knew well.
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