California's New Spider Species Lives At The Beach

Arachnophobia is consistently ranked among the most common phobias, so the discovery of a new spider species on California's beaches will be unwelcome news to many, but for scientists at the University of California, Davis, it's a thrilling breakthrough. In a study published last month in Ecology and Evolution, the world was introduced to Aptostichus ramirezae, a type of trapdoor spider with a plump brown body approximately the size of a quarter. Though they spend most of their time burrowed beneath the dunes, sharp-eyed beachgoers may occasionally see them skittering around the west coast between Monterey Bay and Baja California.

Every year, scientists identify thousands of new animal species, but these discoveries don't always come in the way you might expect. Oftentimes, scientists aren't coming across animals that have never been seen before, but are rather redefining animals we've already encountered. That's the case with Aptostichus ramirezae. These spiders had long been observed on beaches, but they were thought to belong to a different species called Aptostichus simus. This was until arachnologist Jason Bond began to suspect that species differed in different coastal regions.

Gene analysis revealed that Aptostichus ramirezae is a completely different species from Aptostichus simus. Despite looking nearly identical, they are even more genetically distinct from each other than we humans are from chimpanzees. Bond subsequently named the new species after Martina Giselle Ramirez, a trapdoor spider expert renowned within the arachnology world. Though it's only just been identified, there's already a lot to know about this curious species.

The first reaction most people will have to the discovery of a new spider species is to ask a very pertinent question: Is it dangerous? Those people certainly won't be happy to learn that Aptostichus ramirezae is closely related to tarantulas, but thankfully, it's not a dangerous spider species. It is venomous, but the venom is not toxic to humans. Furthermore, the fangs of these spiders are tucked under their face in an orientation that would make it difficult for them to bite a human in the first place. If you're the type of person inclined to pick a spider up, it might bite you in defense, but even then, it would be no more painful than a bee sting.

The insects that live on California's beaches aren't so lucky. Trapdoor spiders like Aptostichus ramirezae are vicious ambush predators. They construct underground burrows in the sand with doors spun from silk that can swing open as if on a hinge. The spiders lurk in wait until they feel the vibrations of their prey passing by, at which point they burst through the trapdoor in a flash, seizing their victims in the ultimate jump scare. It's terrifying to think of, but like other spider species around the world, Aptostichus ramirezae is doing us all a favor by helping to keep insect populations in check. Unfortunately, its ability to do so is now being threatened.

As with so many species on our planet, Aptostichus ramirezae is feeling the effects of climate change on biodiversity in devastating fashion. Erosion from rising sea levels, urban development along the coast, and California's notorious penchant for wildfires have all taken their toll, steadily shrinking these spiders' natural habitat. Both Aptostichus ramirezae and Aptostichus simus are vulnerable species, and now that scientists have now distinguished the two, they've realized the threat is even worse than they thought.

It was long assumed that Aptostichus simus lived all along the coast from Monterey to Mexico, but now scientists have realized that many of those spider populations are actually Aptostichus ramirezae, and that Aptostichus simus almost exclusively lives around San Diego. This makes their population much smaller — and therefore more at risk — than previously thought.

Since Aptostichus ramirezae and Aptostichus simus are two distinct species, they cannot interbreed, and their reclusive lifestyles add another challenge to population growth. Female trapdoor spiders never leave their burrows, and the males never stray far when they go out. This makes each spider population extremely isolated, and thus these species are more vulnerable to extinction. If these spiders vanished from the Golden State, they would no longer control coastal insect populations, and the entire ecosystem could be thrown dangerously out of balance.