Two new sea‑spider species discovered in British Columbia’s Salish Sea

Two previously unknown sea‑spider species have been recorded in the Salish Sea, marking the first finds in that region in more than a century.

Discovery

Researchers from the University of British Columbia collected the tiny animals – about a centimetre across – from shallow waters off Vancouver and Quadra Islands between September 2023 and August 2024. The finds are the first sea‑spider records in the Salish Sea since the early 1900s.

Species Details

One species, Callipallene pilosuspedes, sports red eyes, a triangular three‑lipped mouth and a curved spine that shields its legs. It bears ovigers – belly‑originating limbs used for grooming away dirt and algae – a trait not shared by all sea spiders. The second, Tanystylum kiixin, is named after a nearby ancient Indigenous village; it has shorter, stockier legs that cannot clean, and the specimen was covered in debris when recovered. Lead researcher Cormac Toler‑Scott explained that sea spiders never transitioned to land, remain slow‑moving on the seafloor, and lack venom or fangs. Both new species were attached to hydroids, feeding by piercing the colonial animal and sucking its juices. Their transparent bodies often adopt the colour of their prey, providing camouflage.

Context

Sea spiders belong to the class Pycnogonida, with more than 1,300 known species worldwide. Discoveries like these highlight the still‑poorly explored diversity of shallow marine habitats and may prompt further funding for similar surveys.