Beware, beachgoers: New spider discovered in California’s sand dunes

Just in time for Halloween, researchers have identified a new species of trapdoor spider. The newly discovered Aptostichus ramirezae is about the size of a quarter, brown, and pretty chunky. It’s the fourth known species of trapdoor spiders in California whose habitat is limited to sandy coastal dunes.

Female trapdoor spiders are basically vampires. They spend their entire lives in underground, silky burrows behind a hinged, camouflaged door. They only leave their lair for lunch, when they feel vibrations indicating the passing above of an unfortunate prey. Good thing these tarantula relatives are small. 

In a study recently published in Ecology and Evolution, a team from the University of California, Davis (UC Davis) discovered that this new trapdoor species is closely related to Aptostichus simus. 

“While there are over 50,000 species of spiders worldwide, there are probably hundreds of thousands left to be discovered,” Jason Bond, senior author of the study and a biologist at UC Davis, said in a statement, “even along the coast where new spider species may be hiding just underfoot of California beachgoers.” 

Suspecting that Aptostichus simus was hiding some cryptic species—visually similar but genetically distinct species—the team analyzed the genomic DNA of different specimens from across its range, as well as their distributions. 

“Based on what we know about their natural history and lifestyles, they’re not going to be able to disperse to different coastal dunes to reproduce and ‘mix’ with each other,” said Emma Jochim, a UC Davis doctoral student and study co-author. 

Bond named the new species Aptostichus ramirezae in honor of Martina Giselle Ramirez, an esteemed arachnologist known for his work on trapdoor spider population genetics and dean of the College of Science at California State University, Stanislaus. Previously, Bond has found inspiration for new species names among celebrities and musicians, among others, with examples being Aptostichus stephencolberti, Myrmekiaphila neilyoungi, and Aptostichus barackobamai.

Unfortunately, Aptostichus simus and Aptostichus ramirezae are vulnerable species. They live in limited and shrinking habitats—coastal dunes from central California to northern Baja California, Mexico, and some in the Channel Islands. According to Jochim, the Aptostichus simus lineage is particularly at risk. Researchers have realized that the species today is mostly only found in San Diego, where sea-level rise estimates don’t paint a pretty picture. What’s more, the spiders don’t adapt quickly to new environments. 

Investigating their genetic differences helps scientists recognize the most vulnerable populations. More broadly, tracking spider species sheds light on our planet’s diversity. 

“If we don’t know how many species are in an area or understand the patterns of genetic diversity between populations, we don’t really know what areas would be most important for conservation efforts.”

 

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