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 them forming 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 that includes a single extant family, Liphistiidae, and a number of extinct families. This suborder is thought to form the sister group to all other living spiders, and to retain ancestral characters, such as a segmented abdomen with spinnerets in the middle and two pairs of book lungs. Members of Liphistiidae are medium to large spiders with eight eyes grouped on a tubercle. They are found only in China, Japan, and southeast Asia. The oldest known Mesothelae spiders are known from the Carboniferous, over 300 million years ago.
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.
Hexathelidae is a family of mygalomorph spiders. It is one of a number of families and genera of spiders known as funnel-web spiders. In 2018, the family was substantially reduced in size by genera being moved to three separate families: Atracidae, Macrothelidae and Porrhothelidae. Atracidae includes the most venomous species formerly placed in Hexathelidae.
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.
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:
Myrmekiaphila is a genus of North American mygalomorph trapdoor spiders in the family Euctenizidae, and was first described by G. F. Atkinson in 1886. All described species are endemic to the southeastern United States.
The Euctenizidae are a family of mygalomorph spiders. They are now considered to be more closely related to Idiopidae.
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.
Entypesa is a genus of African mygalomorph spiders in the family Entypesidae. It was first described by Eugène Louis Simon in 1902. Originally placed with the curtain-web spiders, it was transferred to the funnel-web trapdoor spiders in 1985, then to the Entypesidae in 2020. It is a senior synonym of Pseudohermacha.
Pionothele is a genus of African mygalomorph spiders in the family Pycnothelidae. It was first described by William Frederick Purcell in 1902. As of June 2020 it contains three species, found in Namibia and South Africa: P. capensis, P. gobabeb, and P. straminea. Originally placed with the Ctenizidae, it was transferred to the funnel-web trapdoor spiders in 1985, then to the Pycnothelidae in 2020.
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.
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.
Bemmeridae is a family of African and Asian mygalomorph spiders that was first described as the tribe Bemmereae by Eugène Simon in 1903. It was elevated to a subfamily of funnel-web trapdoor spiders (Bemmerinae) in 1985, then to its own family in 2020.
Pycnothelidae is a family of mygalomorph spiders first described in 1917. It was downgraded to a subfamily of the funnel-web trapdoor spiders in 1985, but returned to family status 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, Optova et al. elevated it further to a family.
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.
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.
Nemesioidina is a clade of avicularioid mygalomorph spiders proposed in 2020, based on a molecular phylogenetic analysis.
