New species of trapdoor spider discovered in California

A species of trapdoor spider, named Aptostichus ramirezae, was newly identified by UC Davis scientists. (Credit: Emma Jochim/UC Davis)

One more creepy crawly has been discovered in the sand dunes of California.

Aptostichus ramirezae, is a trapdoor spider described as “brown, chunky” and “quarter-sized,” according to researchers at the University of California Davis.

While previously thought to be the spider Aptostichus simu, a new study has found that ramirezae is actually a separate species.

The arachnophobia-inducing study was published on Oct. 22 in the journal Ecology and Evolution, just in time for Halloween.

Trapdoor spiders are ambush predators, listening for vibrations and popping out to catch prey near their lair.

This group of spiders is related to tarantulas, with female trapdoor spiders living their entire lives underground in burrows. Their burrows are unusual, lined with silk and “sealed with a hinged, camouflaged door,” according to a press release.

Two for the price of one

Aptostichus ramirezae, the newly discovered species, had long been confused with Aptostichus simu by scientists. After studying Aptostichus simu, researchers determined that the two are actually cryptic species. That means a group of organisms that look alike but are genetically different.

Jason Bond, a professor at the University of California Davis and senior author of the study, long suspected that the Aptostichus simu spiders were a look-alike species, but genetic research helped confirm this hunch.

Bond named the new species after Martina Giselle Ramirez, “a highly regarded arachnologist who pioneered early works on trapdoor spider population genetics,” the researchers say.

Bond has previously named other species of spiders after celebrities and political figures, including Aptostichus stephencolberti, Myrmekiaphila neilyoungi and Aptostichus barackobamai.

There are more than 50,000 species of spider catalogued worldwide, but there are likely hundreds of thousands more, “even along the coast where new spider species may be hiding just underfoot of California beachgoers,” according to Bond.

Burrowing through sand dunes

Researchers found the new species’ range to be from Monterey, near San Francisco, all the way down to Baja California, in Mexico.

“Which is a pretty wide range for a trapdoor spider, given that they don’t easily leave their burrows to disperse,” said Emma Jochim, a doctoral student with University of California Davis who was involved in the study.

There are four known species of trapdoor spiders in California that live exclusively in coastal dune habitats, including this new species, the researchers say.

Development, erosion, wildfire and sea-level rise are all contributing factors to shrinking habitats for the newly discovered spider species, according to researchers.

“These spiders are not really able to adapt that quickly to new habitats,” Jochim said.

Aptostichus simu “is now really only found in San Diego,” while the the Aptostichus ramirezae “has a much wider range,” she explained.