The Mygalomorphae, or mygalomorphs, are an infraorder of spiders, and comprise one of three major groups of living spiders with over 3,000 species, found on all continents except Antarctica. Many members are known as trapdoor spiders due to their creation of trapdoors over their burrows. Other prominent groups include Australian funnel web spiders and tarantulas, with the latter accounting for around one third of all mygalomorphs.
The Mesothelae are a suborder of spiders. As of April 2024, two extant families were accepted by the World Spider Catalog, Liphistiidae and Heptathelidae. Alternatively, the Heptathelidae can be treated as a subfamily of a more broadly circumscribed Liphistiidae. There are also a number of extinct families.
Ctenizidae is a small family of mygalomorph spiders that construct burrows with a cork-like trapdoor made of soil, vegetation, and silk. They may be called trapdoor spiders, as are other, similar species, such as those of the families Liphistiidae, Barychelidae, and Cyrtaucheniidae, and some species in the Idiopidae and Nemesiidae. The name comes from the distinctive behavior of the spiders to construct trapdoors, and ambush prey from beneath them.
The family Cyrtaucheniidae, known as wafer-lid trapdoor spiders, are a widespread family of Mygalomorphae spiders.
Crevice weaver spiders (Filistatidae) comprise cribellate spiders with features that have been regarded as "primitive" for araneomorph spiders. They are weavers of funnel or tube webs. The family contains 18 genera and more than 120 described species worldwide.
Hexathelidae is a family of mygalomorph spiders. It is one of a number of families and genera of spiders known as tunnelweb or funnel-web spiders. In 2018, the family was substantially reduced in size by genera being moved to three separate families: Atracidae, Macrothelidae and Porrhothelidae.
Leptonetidae is a family of small spiders adapted to live in dark and moist places such as caves. The family is relatively primitive having diverged around the Middle Jurassic period. They were first described by Eugène Simon in 1890.
Microhexura is a genus of tiny North American spiders that was first described by C. R. Crosby & S. C. Bishop in 1925. It is the only genus in the family Microhexuridae. As of July 2020, it contained only two species, both found in the United States: M. idahoana and M. montivaga. M. montivaga occurs in the higher peaks of the Blue Ridge Mountains of North Carolina and Tennessee. M. idahoana occurs farther west, in the Cascades, the Blue Mountains, and the northern Rocky Mountains.
Cybaeidae is a family of spiders first described by Nathan Banks in 1892. The diving bell spider or water spider Argyroneta aquatica was previously included in this family, but is now in the family Dictynidae.
Dwarf tarantulas, also known as sheet funnel-web spiders are a type of spider from the family Mecicobothriidae. Dwarf tarantulas are one of several families of the suborder Mygalomorphae; this larger group also includes the true tarantulas.
Nemesiidae is a family of mygalomorph spiders first described by Eugène Simon in 1889, and raised to family status in 1985. Before becoming its own family, it was considered part of "Dipluridae". The family is sometimes referred to as wishbone spiders due to the shape of their burrows.
Austrochilidae is a small spider family with nine species in two genera. Austrochilus and Thaida are endemic to the Andean forest of central and southern Chile and adjacent Argentina.
Homalonychus is a genus of araneomorph spiders, and is the only genus in the family Homalonychidae. It was first described by George Marx in 1891. As of October 2023 it contains only two species: H. selenopoides and H. theologus. They are found in the southern United States and Mexico: H. theologus is mostly found west of the Colorado River, while H. selenopoides is mostly found to the east, with some populations in Death Valley and near Mercury, Nevada.
Atypoides is a genus of North American folding trapdoor spiders. It was first described by Octavius Pickard-Cambridge in 1883, and it has only been found in United States. It was synonymized with the genus Antrodiaetus in 2007, but was restored to its former independent status in 2019. As of November 2021, it contains only three species: A. gertschi, A. hadros, and A. riversi.
The Euctenizidae are a family of mygalomorph spiders. They are now considered to be more closely related to Idiopidae.
Hexurella is a genus of spiders, found in the United States and Mexico. It is the only genus in the family Hexurellidae.
Toxopidae is a small family of araneomorph spiders, first described in 1940. For many years it was sunk into Desidae as a subfamily, although doubts were expressed as to whether this was correct. A large-scale molecular phylogenetic study in 2016 led to the family being revived.
Anamidae is a family of Australian mygalomorph spiders. It was first described as a tribe by Simon in 1889, then raised to the subfamily Anaminae of the family Nemesiidae, before being raised to a family level by Opatova et al. in 2020.
Euagridae is a family of mygalomorph spiders. The group was first described as a tribe in 1979 by Robert Raven, who in 1985 elevated it to a subfamily. In 2020, Opatova et al. elevated it further to a family.
The Sitticini are a tribe of spiders in the family Salticidae. The tribe has been divided into two subtribes, Aillutticina, with five Neotropical genera, and Sitticina, with five genera from Eurasia and the Americas. One genus is unplaced within the tribe. The taxonomy of the tribe has been subject to considerable uncertainty. It was clarified in 2020.
