Just in time for Halloween, researchers have identified a new species of trapdoor spider. It’s the fourth known species of trapdoor spiders in California whose habitat is limited to sandy coastal dunes. 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. Image: Emma Jochim / UC Davis. More broadly, tracking spider species sheds light on our planet’s diversity.