Climate change and habitat loss threaten the newly named trapdoor spider.
Scientists from the University of California, Davis, have identified a previously unknown trapdoor spider species lurking in the coastal sand dunes of California. This newly recognized species, Aptostichus ramirezae, shares close evolutionary ties with Aptostichus simus, which inhabits coastal areas stretching from Monterey down to Baja California, Mexico.
According to research published in Ecology and Evolution, what researchers previously thought was a single species has turned out to be two distinct ones.
“While there are over 50,000 species of spiders worldwide, there are probably hundreds of thousands left to be discovered, even along the coast where new spider species may be hiding just underfoot of California beachgoers,” said senior author Jason Bond, a professor in the UC Davis Department of Entomology and Nematology.
A hidden species revealed
Trapdoor spiders belong to a group of small, reclusive arachnids related to tarantulas. Female trapdoor spiders spend their entire existence below ground inside burrows lined with silk and covered by a hinged door that blends into the surroundings. They remain motionless while sensing vibrations from above, only venturing out to capture prey that strays too near their concealed entrance.
“There are now four known species of trapdoor spiders in California that live exclusively in coastal dune habitats,” said corresponding author Emma Jochim, a doctoral student in the UC Davis Department of Entomology and Nematology. “The one we were looking at as part of this study was the most widespread, ranging from Moss Landing near Monterey down to Baja California — which is a pretty wide range for a trapdoor spider, given that they don’t easily leave their burrows to disperse.”
Jochim and her colleagues analyzed genomic DNA from Aptostichus simus spiders collected across that range. Bond long suspected that it comprised cryptic species, meaning it was one of two or more species that look nearly identical but are genetically different.
Researchers looked not just at molecular data, but also their distribution. Cryptic species are reproductively isolated.
“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,” Jochim said.
What’s in a name
Professor Jason Bond decided to name the new brown, chunky, quarter-sized spider Aptostichus ramirezae. Bond is no stranger to naming new spider species. The arachnologist has named species after celebrities, musicians, photographers, and even magicians. Notables include Aptostichus stephencolberti or Myrmekiaphila neilyoungi and Aptostichus barackobamai.
This new species is named for Martina Giselle Ramirez, dean of the College of Science at California State University, Stanislaus, and formerly dean of natural sciences and biology professor at St. Norbert College. Ramirez is a highly regarded arachnologist who pioneered early works on trapdoor spider population genetics and has championed underrepresented students in STEM disciplines.
More than a Halloween creature
The scariest part about this discovery isn’t the spider, it’s what could happen if its home is lost for good.
Both Aptostichus simus and Aptostichus ramirezae live only in coastal dunes from central California to northern Baja California, Mexico, including some in the Channel Islands. These habitats are shrinking due to many factors, including development, erosion, wildfire, and sea-level rise.
“They’re definitely at risk, especially the lineage Aptostichus simus,” Jochim said. “The new species has a much wider range, but Aptostichus simus is now really only found in San Diego, and projections for sea-level rise in that area are very grim. These spiders are not really able to adapt that quickly to new habitats.”
Understanding genetic differences among these spiders helps scientists identify which populations most need protection. While it may seem spooky to study spiders, Jochim said documenting spiders helps us understand the diversity of our planet.
“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,” she said.
Reference: “Speciation Pattern and Process in the California Coastal Dune Endemic Trapdoor Spider Aptostichus simus (Mygalomorphae: Euctenizidae) and Description of a New Cryptic Species” by Emma E. Jochim, James Starrett, Hanna R. Briggs and Jason E. Bond, 22 October 2025, Ecology and Evolution.
DOI: 10.1002/ece3.72346
Other authors of the study include James Starrett and Hanna R. Briggs with UC Davis. The work was supported by the National Science Foundation.
Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.
21 Comments
so, professor, when, exactly are we going to see this “sea level rise” that our “climate catastrophe” is going to render? For 50 years global warming claims have put coastal cities underwater in “the next 12 years”. Yet, here we are, with a net zero sea level rise. also, would you, please, show how this species “evolved” from other trapdoor spiders. I see the genetic markers, but we dont have the comparative link from one to the other. Perhaps you are a scientist that believes “the transformation happened at a critical mass point, where the species morphed in a single generation.” We have so many things in science that are happening that are truely amazing, does a cousin spider rate that importance?
Ask your question about sea level rise to people who live on the East Coast USA.
OMG 😱! What kind of spider is that? We got all these different viruses to deal with. I really wish that some people would stop smuggling all these different insects and animals into the United States.
Yeah well if you look at the sea wall at battery park today and compare it to a picture from 50 years ago it is at the very same level. So explain that one
What nonsense. Are you familiar with the term “straw man argument?”
Great. Now the environmental terrorists will use this as leverage to seize miles of land for “sanctuary” status for a fking spider. This is why high speed rail took so long because it had to avoid all the special little zones the peta crowd hijacked. California is a toilet
Thats it Dave, make people even More unnecessarily afraid of spiders because you wanted to use a reaction invoking title for your “article.”
There’s nothing scary about this spider beyond you thinking you’re suppose to be afraid of them because people like Dave want to perpetuate the unnecessary fear.
California deserves it commie state
We couldn’t have an otherwise interesting article about nature without the climate change references. I stopped reading stories like this years ago, but yeah, cool spider!
Coop
That’s not scary.
“projections for sea-level rise”. Well, lost my confidence in any of your opinions Mr. Scientist!
I live on the coast of Nova Scotia and I don’t see sea level rising either
Spiders know what pants are.
Just found this guy on my black leggings. He was cannibalised by another spider. The females do this. They can have hundreds of young and if theres no food source or even if their is they will eat their young. Moreover i think this one was about territory because leggings.
This will be the fourth occasion i have found them amoungst pants. Ive had them in my leggings before and ive been bit in the groin twice. And these are nasty bites. Up until four years ago i had never been biten by a spider. The video of my groin is in google photos. Ive been biten so much and so has kyle thst we dont even go to the er we know exactly what to put on it(which we are out of: mupirocin) and we already have the antibiotics on hand.
And doctors are so fucking oblivious and dumb and obviously in denial because the truth is gruesome. They will tell you there are no spiders in washington that will bite you and while this one is not a brown recluse it is a hobo spider, the doctors are in denial that the brown recluse does in fact live here too. And both of them bite people. And how fucking sad that i have to be the one who knows all this shit because obviously i dont want to and i dont fucking care. I just feel like let down by the individuals who took an oath to do no harm and to maybe raise a red flag when someone walks into the er complaining of spider bites becuase th a t could be a major health concern yes but also a threat to public safety that if there were awareness people could at least take better measures at protecting themselves from this. Except i kind of know why they dont care: their prey is exactly calculated who they hunt it is insane.
I have found spiders in kyles long underware. Even just folding them after sitting on a shelf for weeks. They fucking wait there. Spiders know what those things are and where we put them. This makes them so much smarter than i thought because the spider doesnt even need to approach its prey it just needs to sit there .
Also this is why i think certain prey are targeted: i have seen spiders using the roads at night. I am not even fucking joking they will walk long distances using the road usually around 3 in the morning. They also target people who smoke fentnyl because they are attracted to the drug that is in their blood it has something to do with the chemical they put into prey when they bite them. The venom that melts insects insides and turns them to jelly, it is similar to that. Now why send the alarm if a bunch of drugs addicts walk into the er complaining about spiders am i right? There are too many and the evidence is very obvious that that is a fucking bite you just use prejudice and group us into the nuts who believe in conspiracy theories about the cia and crap like that.
This is why i know they are calculating: not only will they bite you, they might bit you more than once but at different times and in the same placr so thst you think it is the same bite. That way they get multiple feedings and i know what you are thinking why would the spider care if i know how many times it bit me? Why did it pick my house? Im not really going to speculate on that but i know some of you know exactly what im talking about that its more than one bite. No its not that you are healing slowely, these little creatures are fucking murderous monsters that sit around and plan the shit out even till the end when it drags things out for you to multiply your pain and trick you into never taking precautions against acts like this. Because its a bug. Obviously we should be able to figure that one out amd they know this and thats why they do all this sneaky shit. Just look at the photos and video of the back of kyles head. I told him the spider wasbt coming back but thst it was the matrix arm as a joke but now im noticing my armpits look strangely like one three prong and one four prong adapter matrixs arm but i dont know i was wrong about those things in my window the other night: those were just leaves. Its probably the meth but who knows. Lol
You suffer from arachnophobia.
Sabina I mean this in the nicest way possible, but, you dont know what youre talking about. I can see your train of thought(s) and how they make your points seem valid, but they’re not.
There are too many to refute every single one but just for starters spiders dont feed off of people. Its literally impossible even for the largest spiders in the world because their digestive enzymes cant break down human tissue effectively enough to consume it. And thats if one even tried but they dont try this because they already know this, plus the risk/benefit ratio keeps them where they would never even consider it. And thats even if they could consider anything since they dont even have the ability to have complex thoughts or ideas.
We also seen one of those in South Africa many times.
You know this species was discovered over a month ago correct? You’re just piggybacking off of content that already exists. Try being original for a change, all you small time self proclaimed “journalists” are all the same.
Climate change.. 😂😂😂
I found one of these in Sonora, California Sierra Nevada. It was inside what looked like a pvc sticking out side of hill. Well the Pvc was actually it’s nest and inside was one of these bout quarter sized along with a ton of its babies, little tiny white spiders.
Climate change is a made up hoax and you should be ashamed of yourself for trying to pedal this trash. Obviously you can see by the previous comments that the youth of the world can see through your lies. When I was a child in the ’70s they said it was global cooling and they were afraid of a new ice age and then as I got older they were like ooh we were wrong it’s a global warming in the oceans are going to consume our planet. But as time goes on the only thing that is revealed is your lies and the lies of the rich bastards who think they are in charge claiming global warming so you sell your land on the beach and they buy it up for pennies. Look Barack Obama just bought a multi million dollar mansion on the beach. Why would he do that if the oceans were going to consume the beaches?