The Mygalomorphae, or mygalomorphs, are an infraorder of spiders, and comprise one of three major groups of living spiders with over 3000 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.
Atracidae is a family of mygalomorph spiders, commonly known as Australian funnel-web spiders or atracids. It has been included as a subfamily of the Hexathelidae, but is now recognised as a separate family. All members of the family are native to Australia. Atracidae consists of three genera: Atrax, Hadronyche, and Illawarra, comprising 35 species. Some members of the family produce venom that is dangerous to humans, and bites by spiders of six of the species have caused severe injuries to victims. The bites of the Sydney funnel-web spider and northern tree-dwelling funnel-web spider are potentially deadly, but no fatalities have occurred since the introduction of modern first-aid techniques and antivenom.
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.
Antrodiaetidae, also known as folding trapdoor spiders or folding-door spiders, is a small spider family related to atypical tarantulas. They are found almost exclusively in the western and midwestern United States, from California to Washington and east to the Appalachian mountains. Exceptions include Antrodiaetus roretzi and Antrodiaetus yesoensis, which are endemic to Japan and are considered relict species. It is likely that two separate vicariance events led to the evolution of these two species.
Atypoidea is a clade of mygalomorph spiders, one of the two main groups into which the mygalomorphs are divided. It has been treated at the rank of superfamily. It contains five families of spiders:
The evolution of spiders has been ongoing for at least 380 million years. The group's origins lie within an arachnid sub-group defined by the presence of book lungs ; the arachnids as a whole evolved from aquatic chelicerate ancestors. More than 45,000 extant species have been described, organised taxonomically in 3,958 genera and 114 families. There may be more than 120,000 species. Fossil diversity rates make up a larger proportion than extant diversity would suggest with 1,593 arachnid species described out of 1,952 recognized chelicerates. Both extant and fossil species are described annually by researchers in the field. Major developments in spider evolution include the development of spinnerets and silk secretion.
Ischyropsalididae is a family of harvestmen with 35 described species in 3 genera, found in Europe and North America.
Porrhothele is a genus of mygalomorph spiders endemic to New Zealand. They are the only members of the family Porrhothelidae. They were first described by Eugène Louis Simon in 1892. Originally placed with the curtain web spiders, it was moved to the Hexathelidae in 1980, they were placed in their own family in 2018.
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.
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.
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.
Rosamygale is a genus of extinct Triassic spiders, with a single described species, Rosamygale grauvogeli. It is the oldest known member of the Mygalomorphae, one of the three main divisions of spiders, which includes well known forms such as tarantulas and Australian funnel-web spiders. It was described by Selden and Gall in 1992, from specimens found in the Middle Triassic aged Gres a Meules and Grès à Voltzia geological formations in France. It is also considered to be the oldest known member of the Avicularioidea, one of the two main divisions of Mygalomorphae.
Hexura is a genus of American folding trapdoor spiders that was first described by Eugène Louis Simon in 1884. As of September 2019 it contains two species, found in the United States: H. picea and H. rothi. Originally placed with Mecicobothriidae, it was moved to Antrodiaetidae in 2019.
Antrodiaetus pacificus is a species of mygalomorph spiders native to the Pacific Northwest. Both male and female were first described by French arachnologist Eugène Louis Simon in 1884 under the name Brachybothrium pacificum. The genus name is a combination of the Greek "antrodiaitos" (αντροδιαιτος), meaning "living in caves", "antron" (αντρον), meaning "cave", and "diaita (διαιτα), meaning "way of life, dwelling". The specific epithet refers to its geographical distribution along the pacific coast of North America, between San Francisco Bay and Alaska. It is the northernmost mygalomorph spider in North America.
Theromaster is a genus of armoured harvestmen in the family Cladonychiidae. There are at least two described species in Theromaster, found in the eastern United States.
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.
Domiothelina 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 domed apical segment of the posterior lateral spinnerets. The clade has been supported to some degree by subsequent molecular analyses, although with a somewhat different composition.
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.
Theraphosoidina is a clade of avicularioid mygalomorph spiders first proposed by Robert J. Raven in 1985, based on a morphological cladistic analysis. Raven included three families: Theraphosidae, Paratropididae and Barychelidae. Subsequent molecular phylogenetic studies upheld the relationship between the Theraphosidae and Barychelidae, but found that Paratropidae fell outside the clade.
