Meet the hairy-legged, red-eyed sea spiders new to science
Two new species of sea spider have been discovered in the Salish Sea – the first to be described there in almost a century – filling a longstanding gap in scientific understanding of one of the ocean’s most overlooked animal groups.
The species, documented and genetically analysed by researchers at the University of British Columbia (UBC), are described in a study recently published in Organisms Diversity & Evolution.
“I was interested in how sea spiders are impacted by climate change and human disturbance, because marine invertebrates in the Salish Sea are particularly at-risk, and I couldn’t find anything,” said lead author Cormac Toler-Scott, who carried out the research as part of his master’s degree in zoology at UBC. “That’s largely because people don’t know much about what species exist here and what their lifestyle is.”
Toler-Scott says the knowledge gap extends well beyond sea spiders to marine arthropods more broadly. “In order to understand how marine invertebrates are being impacted by things like climate change and how we can better protect these key elements of the ecosystem, we have to be able to identify them.”
Sea spiders are, in fact, distant relatives of scorpions, spiders and horseshoe crabs, having evolved roughly 500 million years ago and remained in the ocean ever since. They share their arachnid cousins’ leggy build – with as many as 12 limbs in some species – alongside a distinctive sucking proboscis. Size varies dramatically across the group, from less than a centimetre to more than 70cm in Antarctic waters, where the largest species hunt smaller prey in the deep.
Many of the smaller, shallow-water species have adopted a parasitic lifestyle, living on larger host organisms.
“They’ve retained some weird traits,” said Toler-Scott. “A lot of the shallow water species are quite small, and so they’ll live as parasites on larger organisms, and they use this weird apparatus called a proboscis to suck the juices out of their host.”
