Aliatypus

Aliatypus is a genus of North American folding trapdoor spiders first described by Chas. Piper 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.