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.
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.
Lampshade spiders, family Hypochilidae, are among the most primitive of araneomorph spiders. There are two genera and twelve species currently recognized. Like mygalomorphs, most hypochilids have two pairs of book lungs, but like araneomorphs they have intersecting fangs, with the exception of some species which have chelicerae in an angle that is neither orthognathous or labidognathous. These long-legged spiders build typical "lampshade" style webs under overhangs and in caves. In the United States the fauna is primarily associated with the Appalachian, Rocky and California Mountains. Ten of the known species are found in these ranges, all in the genus Hypochilus. The genus Ectatosticta is found in China.
Spider taxonomy is that part of taxonomy that is concerned with the science of naming, defining and classifying all spiders, members of the Araneae order of the arthropod class Arachnida with more than 48,500 described species. However, there are likely many species that have escaped the human eye to this day, and many specimens stored in collections waiting to be described and classified. It is estimated that only one third to one half of the total number of existing species have been described.
The Austrochiloidea or austrochiloids are a group of araneomorph spiders, treated as a superfamily. The taxon contains two families of eight-eyed spiders:
Myrmekiaphila neilyoungi is a species of spider in the family Euctenizidae, described in 2007 by East Carolina University professor of biology Jason E. Bond and Norman I. Platnick, curator at the American Museum of Natural History in New York City. It is named after Canadian rock musician Neil Young.
Aptostichus is a genus of North American mygalomorph spiders in the family Euctenizidae, and was first described by Eugène Simon in 1891. They are found predominantly in southern California, United States.
Aptostichus angelinajolieae, the Angelina Jolie trapdoor spider, is a species of Euctenizidae, nocturnal arthropods who seize their prey after leaping out of their burrows and inject it with venom. It was described by the Auburn University professor Jason Bond in 2008, who named it after the American actress Angelina Jolie in recognition of her work on the United Nations High Commission for Refugees. It was one of only seven described species of Aptostichus until 2012, when it was joined by Bono's Joshua Tree trapdoor spider and 32 other species.
The Euctenizidae are a family of mygalomorph spiders. They are now considered to be more closely related to Idiopidae.
Ummidia is a genus of mygalomorph spiders in the family Halonoproctidae, and was first described by Tamerlan Thorell in 1875.
Eucteniza is a genus of trapdoor spiders in the family Euctenizidae containing at least 14 species occurring in Mexico and the southern United States. Species are distinguished by a softened rear portion of the carapace, and males possess large spines on the first two pairs of walking legs that are used to hold females during mating. Like other trapdoor spiders they create burrows with a hinged lid, from which they await passing insects and other arthropods to prey upon. Many species are known from only one or two localities, or from only male specimens. More species are expected to be discovered. Eucteniza is closely related to spiders of the genera Entychides and Neoapachella.
Entychides is a genus of mygalomorph trapdoor spiders in the family Euctenizidae, and was first described by Eugène Simon in 1888. Originally placed with the Ctenizidae, it was moved to the wafer trapdoor spiders in 1985, then to the Euctenizidae in 2012.
Apomastus is a genus of North American mygalomorph spiders in the family Euctenizidae, and was first described by Jason Bond & B. D. Opell in 2002. As of May 2019 it contains only two species, both found in the Los Angeles Basin of southern California: A. kristenae and A. schlingeri.
Promyrmekiaphila clathrata is a species of wafer-lid trapdoor spider in the family Euctenizidae that is endemic to the state of California in the United States. Its range is restricted to the central and northern California Coast Ranges, from San Benito County to Glenn County. Like its sister species, C. winnemem, it can be distinguished from species in similar genera by the dusky chevron pattern on its abdomen. It prefers vegetated, mesic habitats that retain some moisture, where it builds burrows in soil up to 30 cm deep. Like other members of this family, it covers its burrow entrance with a door made of silk and soil.
Halonoproctidae is a family of mygalomorph spiders, split off from the family Ctenizidae in 2018. Species in the family are widely distributed in North and Central America, Australasia, Asia, southern Europe and North Africa. One species is recorded from Venezuela in South America. They are relatively large, sombrely coloured spiders, that live in burrows with some kind of trapdoor.
Avicularioidea is a clade of mygalomorph spiders, one of the two main clades into which mygalomorphs are divided. It has been treated at the rank of superfamily.
Bipectina is a clade of avicularioid mygalomorph spiders first proposed by Pablo A. Goloboff in 1993, based on a morphological cladistic analysis. The clade was marked by a number of morphological features, and in particular by the presence of two rows of teeth on the superior tarsal claws of the legs of both sexes, meaning that the claws were bipectinate. The clade was supported by some subsequent analyses, although not all. A major phylogenetic study in 2020 upheld the monophyly of the clade, which contained 19 of the 25 accepted families of the Avicularioidea.
Crassitarsae is a clade of avicularioid mygalomorph spiders first proposed by Robert J. Raven in 1985, based on a morphological cladistic analysis. Raven characterized the clade by a number of shared features, including the presence of some scopulae on the tarsi. The clade has been supported to some degree by subsequent molecular analyses, although with a somewhat different composition.
