Aliatypus

Aliatypus is a genus of North American folding trapdoor spiders first described by C. P. Smith in 1908. They resemble members of Ctenizidae in morphology and behavior, but this is due to convergent evolution rather than direct relation. They are most closely related to members of Antrodiaetus, which build collar doors. It is likely that the shift from using collar doors to using trapdoors is what allowed them to survive in hot, dry conditions where their closest relatives could not.

Often found in roadside banks or ravines, they build a burrow perpendicular to the surface with a wafer-like trapdoor entrance to catch prey. Burrows are often clustered together, sometimes quite densely in more favorable positions.

They are native to the western United States, where the complex landscape creates pockets of isolated species limited to small regions. As one of the most abundant genera of trapdoor spiders in California, it is argued that their sedentary lifestyle and limited dispersal could benefit studies in the biogeography of California and the surrounding regions.

Species
it contains fourteen species, all found in the southwestern United States:
 * Aliatypus aquilonius Coyle, 1974 – USA
 * Aliatypus californicus (Banks, 1896) – USA
 * Aliatypus coylei Hedin & Carlson, 2011 – USA
 * Aliatypus erebus Coyle, 1974 – USA
 * Aliatypus gnomus Coyle, 1974 – USA
 * Aliatypus gulosus Coyle, 1974 – USA
 * Aliatypus isolatus Coyle, 1974 – USA
 * Aliatypus janus Coyle, 1974 – USA
 * Aliatypus plutonis Coyle, 1974 – USA
 * Aliatypus roxxiae Satler & Hedin, 2013 – USA
 * Aliatypus starretti Satler & Hedin, 2013 – USA
 * Aliatypus thompsoni Coyle, 1974 – USA
 * Aliatypus torridus Coyle, 1974 – USA
 * Aliatypus trophonius Coyle, 1974 – USA