If the mere sight of a spider gives you goosebumps, you may find two species of sea spiders recently discovered by scientists even more disturbing.
Researchers in Canada discovered two previously unknown species of sea spiders during scuba diving operations, at depths of up to 18 metres, between September 2023 and August 2024, in the Salish Sea, which is located between the western Canadian province of British Columbia and the US state of Washington.
According to the study published in the journal "Organisms Diversity & Evolution" on Wednesday, one of the two species is characterized by long, curved spines covering the lower parts of its legs. It was given the name Callipallene pilosuspedes, as "pilosus" in Latin means "hairy" and "pedes" means "feet."
This creature, which has a slender torso, is also characterized by red eyes and three lips at the opening of its triangular mouth, in addition to claws.
It also has appendages that have “a great deal of flexibility and dexterity,” which resemble legs but are not used for walking. They can “serve as cleaning, care, and body tools,” according to a statement issued by the University of British Columbia, which conducted the study, on Wednesday.
“Under the microscope, the researchers observed the animal wrapping these appendages around its legs, and using attached spines resembling combs to clean itself,” the statement said.
In contrast to Callipallene pilosuspedes, the limbs that the newly discovered species, Tanystylum kiixin, uses to carry eggs "are much smaller and less flexible, rendering the animal unable to clean itself effectively," according to the University of British Columbia.
The word "kiixin" in its name is derived from the sound of waves hitting the base of an ancient indigenous village site where this species was found, according to the study.
This spider is characterized by an hourglass-shaped abdomen, black eyes, and claws that resemble knots or protrusions.
Although it is a parasite in its own right, it has frequently been found to be “covered in its own tiny parasites,” the University of British Columbia added.
Overall, scientists have identified nearly 1,400 species of sea spiders, whose origin dates back about 500 million years, according to the study.
These marine arthropods can crawl on the ocean floor or move on animals or plants, and some of them can even walk on the surface of the water. Their sizes range from less than one centimeter to 70 centimetres, according to the University of British Columbia.
These animals are not actual spiders, but are evolutionary related to spiders, as well as scorpions and horseshoe crabs, according to the university. It has four trunk segments and four pairs of long legs, although some species may have up to 12 legs. Species that live in shallow water often have four eyes.
Their mouths are usually larger than their bodies, and they use them to suck liquids from soft-bodied invertebrates. Their digestive and reproductive systems also branch out within their legs, and males carry the eggs on a distinctive pair of legs until they hatch.
In this study, researchers decided to describe sea spiders that live in the shallow waters of the Salish Sea because only 17 species had been reliably documented in the region, despite the sea's rich marine biodiversity, according to the study.
The study's lead author, biologist Cormac Toller-Scott, who conducted the research as part of his master's thesis in zoology at the University of British Columbia, noted in the statement, "I was interested in learning how sea spiders would be affected by climate change and human-caused disturbances, because marine invertebrates in the Salish Sea are particularly vulnerable, but I was unable to find almost any information. This is largely because people don't know much about the species here or about their lifestyle."
With the coasts surrounding the sea now densely populated and rapidly developing, the researchers noted that documenting the biodiversity in its waters is “an important step in identifying where conservation efforts can have the greatest impact,” in the face of threats to the sea from human activities.
