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 family Dipluridae, known as curtain-web spiders are a group of spiders in the infraorder Mygalomorphae, that have two pairs of booklungs, and chelicerae (fangs) that move up and down in a stabbing motion. A number of genera, including that of the Sydney funnel-web spider (Atrax), used to be classified in this family but have now been moved to Atracidae.
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.
Heptathela is a genus of spiders that includes the Kimura spider. They are trapdoor spiders of the family Heptathelidae and are found in Japan, including Okinawa and the Ryukyu Islands. Spiders of this genus lack venom glands.
Ochyroceratidae is a six-eyed spider family, with 165 described species in ten genera. They are common inhabitants of caves and the tropical forest litter of South Africa, the Caribbean, Asia and South America. Considered an ecological counterpart of the Linyphiidae of the northern temperate zone, species are especially diverse in the Indo-Pacific region.
Anapidae is a family of rather small spiders with 232 described species in 58 genera. It includes the former family Micropholcommatidae as the subfamily Micropholcommatinae, and the former family Holarchaeidae. Most species are less than 2 millimetres (0.079 in) long.
Opisthothelae is a suborder of spiders within the order Araneae, containing Mygalomorphae and Araneomorphae, but excluding Mesothelae. The Opisthothelae are sometimes presented as an unranked clade and sometimes as a suborder of Araneae. In the latter case, Mygalomorphae and Araneomorphae are treated as infraorders.
Liphistius is a genus of basal trapdoor spiders in the family Liphistiidae. They are found in Japan, China, and Southeast Asia.
Ryuthela is a spider genus in the family Heptathelidae. This genus, as well as their closest relatives, Heptathela, formed when land masses from present-day Japan separated from the rest of Asia, forming islands in the late Miocene. Speciation of Ryuthela and Heptathela also occurred during this time, because of the further separation of islands, causing allopatric speciation.
Burmesarchaea is a diverse extinct genus of spiders, placed in the family Archaeidae. The type species Burmesarchaea grimaldii was first described in 2003 and least 13 more species have been assigned to the genus. The genus has been exclusively found in Cretaceous Burmese amber, which is dated to 99 million years ago.
Ganthela is a genus of spiders in the family Heptathelidae. It was first described in 2015 by Xu & Kuntner. As of 2017, it contains 7 species, all of them from China.
Qiongthela is a genus of spiders in the family Heptathelidae. As of 2021, it contains 14 species.
Chthonopes is a genus of southeast Asian ray spiders that was first described by J. Wunderlich in 2011. As of June 2020 it contains three species, found in caves of Laos, but can likely also be found in India and China: C. cavernicola, C. jaegeri, and C. thakekensis. They have several adaptations for darker environments, including pale coloration, long legs, and reduced lenses.
Chimerarachne is a genus of extinct arachnids, containing five species. Fossils of Chimerarachne were discovered in Burmese amber from Myanmar which dates to the mid-Cretaceous, about 100 million years ago. It is thought to be closely related to spiders, but outside any living spider clade. The earliest spider fossils are from the Carboniferous, requiring at least a 170 myr ghost lineage with no fossil record. The size of the animal is quite small, being only 2.5 millimetres (0.098 in) in body length, with the tail being about 3 millimetres (0.12 in) in length. These fossils resemble spiders in having two of their key defining features: spinnerets for spinning silk, and a modified male organ on the pedipalp for transferring sperm. At the same time they retain a whip-like tail, rather like that of a whip scorpion and uraraneids. Chimerarachne is not ancestral to spiders, being much younger than the oldest spiders which are known from the Carboniferous, but it appears to be a late survivor of an extinct group which was probably very close to the origins of spiders. It suggests that there used to be spider-like animals with tails which lived alongside true spiders for at least 200 million years.
Priscaleclercera is a genus of araneomorph spiders in the family Psilodercidae, containing seven species. The genus was first described by Jorge Wunderlich in 2017, and its fossils have been found in Burmese amber, while live specimens have been found in Indonesia (Sulawesi).
Lagonomegopidae is an extinct family of spiders known from the Cretaceous period. Members of the family are distinguished by a large pair of eyes, positioned on the anterolateral flanks of the carapace, with the rest of the eyes being small. They have generally been considered members of Palpimanoidea, but this has recently been questioned. Members of the family are known from the late Early Cretaceous (Albian) to near the end of the Late Cretaceous (Campanian) of Eurasia, North America and the Middle East, which was then attached to Africa as part of Gondwana. They are generally assumed to have been free living hunters as opposed to web builders.
Jörg Wunderlich is a German arachnologist and palaeontologist. He is best known for his study of spiders in amber, describing over 1000 species, 300 genera, 50 tribes/subfamilies and 18 families in over 180 publications. Unlike most other arachnologists Jörg has never held any academic position and has worked as a private individual with no financial support for travel or equipment.
Heptathelidae is a family of spiders. It was formerly sunk within the family Liphistiidae, but as of December 2023 was accepted by the World Spider Catalog.
