Two species of marine arthropods new to science 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. The finds were made by a research team at the University of British Columbia, and according to the researchers, they are the first sea spiders recorded from that stretch of water in more than 100 years.
The team was led by Cormac Toler-Scott, a researcher at the university, who discussed the discovery with NPR. The two animals are sea spiders, a group that looks remarkably like the spiders people encounter on land but belongs to an entirely separate branch of the arthropod family tree. In keeping with that lineage, the newly described species bear no resemblance to the jumping, web-spinning, eight-legged creatures most people picture when they hear the word "spider" — and there is no prospect of either species showing up indoors.
Both new species are tiny, measuring roughly a centimeter across from tip to tip. They were collected in a series of sampling efforts conducted between September 2023 and August 2024, in waters surrounding the islands of Vancouver and Quadra, two of the larger islands in the Salish Sea off the British Columbia coast. The specimens turned up in shallow water, close enough to shore that the discovery was not the product of a deep-sea expedition.
The timing of that collecting window — a full year of field seasons, spanning every season — points to a sustained survey effort rather than a chance encounter. Animals a centimeter wide are easily overlooked, particularly in water where visibility is limited and the seafloor is covered in kelp, sediment and debris. Sustained sampling over consecutive seasons raises the odds of turning up rare, small-bodied creatures that a single trip might miss.
Sea spiders are marine arthropods belonging to the class *Pycnogonida*. Scientists have now identified more than 1,300 species in the class, and the two Canadian finds add to that growing tally. Despite the name, sea spiders are not true spiders: they are more closely allied with the sea creatures known as crabs and lobsters than with the tarantulas and orb-weavers of terrestrial gardens. What they share with land spiders is a superficial resemblance — an elongated body carried on what appear to be eight slender legs — that has long made the group a source of fascination for anyone who pulls one up in a net.
Toler-Scott noted that some sea spiders not only look like their land-based counterparts but are, in a broad sense, related to them. Yet the differences are significant. "They never made that transition to land," Toler-Scott said. "They really need to be in the water. They're quite slow moving. They just kind of crawl on the seafloor."
That lifestyle has consequences for how the animals live. Because they are always submerged, they do not face the drying-out problem that limits where land spiders can thrive, and their slow, deliberate movement is a feature of an animal that is at home in a three-dimensional marine environment rather than a hurry to flee a predator on open ground. They are, in effect, specialists of the seafloor — a habitat where a centimeter of size offers camouflage rather than protection.
One of the two new species, *Callipallene pilosuspedes*, is described in unusually vivid detail. According to the team's observations, it has red eyes, a three-lipped mouth shaped like a triangle, and a curved spine that extends over and covers its legs. It also carries a set of unusual limbs that grow from the underside of its body, called ovigers. In sea spiders, these structures are used for grooming and for combing dirt and debris off the animal's own legs and body — a tidy-up routine that matters more in seawater, where sediment and organic material cling to every surface.
The second species, *Tanystylum kiixin*, was photographed with round eggs visible inside its legs. The image, credited to Cormac Toler-Scott and the University of British Columbia, captures a brooding animal carrying its young close to its body rather than releasing them into the surrounding water — a reproductive arrangement that keeps eggs protected during the vulnerable early stages of development.
The discovery carries significance well beyond the naming of two small marine invertebrates. A gap of more than a century between the previous sea spider record in the Salish Sea and these collections suggests not that the animals were absent from the region, but that they had gone largely unnoticed. That is a common pattern in marine biology: species that are small, slow-moving and unremarkable in a home aquarium can persist undetected for generations simply because no one has looked closely enough, or often enough, to describe them.
For the researchers, the practical significance of finding two new species in familiar coastal water is a reminder of how incomplete the map of ocean biodiversity remains. More than 1,300 sea spider species are known, yet the class was recognized as recently as the mid-20th century and new members continue to turn up in places with heavy shipping traffic, dense human settlement and well-trodded beaches. Each new description expands the reference collection against which future specimens are compared — and each one marks a piece of the seafloor that has, until now, gone unrecorded.
The discovery was reported by NPR's Chandelis Duster on September 27, 2026. For anyone hoping to encounter the new species, the news is reassuringly academic: they require full submersion, they move slowly across the seafloor, and they are not, in any sense, house spiders.
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