Euctenizidae

The Euctenizidae (formerly Cyrtaucheniidae subfamily Euctenizinae) are a family of mygalomorph spiders. They are now considered to be more closely related to Idiopidae. The name comes from the Greek prefix εὖ- (eu-), meaning 'valuable' or 'good', which had been thought that the family Ctenizidae possess these traits. Many, but not all, make wafer-like doors to their burrows, while others build the cork-like doors found commonly in the true trapdoor spiders. The biology of nearly all of the species is poorly known. The family occurs almost exclusively in the United States and Mexico. Common U.S. genera include Myrmekiaphila, Aptostichus and Promyrmekiaphila. As of April 2019, the World Spider Catalog accepts the following genera: