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.
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.
Oecobiidae, also called disc web spiders, is a family of araneomorph spiders, including about 100 described species. They are small to moderate sized spiders, about 2 to 20 millimetres long combined head and body length, depending on the species. Larger ones tend to be desert-dwelling. The legs are unusually evenly placed around the prosoma; most other spiders have some legs directed clearly forward and the rest clearly backward, or all forward. The first two pairs of legs of many Oecobiids point forward then curve backwards. This gives a scurrying, wheel-like impression that is characteristic of many Oecobiidae, and is helpful as a rough aid to identification in the field. Characteristic of the family is the anal gland; it bears a tuft of long hairs. Typical colour patterns range from dark-patterned cream in some smaller species, to a small number of symmetrically placed, conspicuous round light spots on a background that may be anything from a dull orange colour to black. The carapace is rounded and bears a compact group of six to eight eyes medially situated near the front of its dorsal surface.
Spider taxonomy is the 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, which has more than 48,500 described species. However, there are likely many species that have escaped the human eye as well as 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.
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.
Phyxelididae is a family of araneomorph spiders first described by Pekka T. Lehtinen in 1967 as a subfamily of Amaurobiidae, and later elevated to family status as a sister group of Titanoecidae.
Stenochilidae is a family of southeast Asian araneomorph spiders that produce ecribellate silk. First described by Tamerlan Thorell in 1873, it now contains twelve described species in two genera.
Palpimanidae, also known as palp-footed spiders, is a family of araneomorph spiders first described by Tamerlan Thorell in 1890. They are widely distributed throughout the tropical and subtropical regions of the world, the Mediterranean and one in Uzbekistan, but not Australia. They are not common and there is a high degree of endemism.
The Deinopoidea or deinopoids are group of cribellate araneomorph spiders that may be treated as a superfamily. As usually circumscribed, the group contains two families: Deinopidae and Uloboridae.
The Agelenoidea or agelenoids are a superfamily or informal group of entelegyne araneomorph spiders. Phylogenetic studies since 2000 have not consistently recovered such a group, with more recent studies rejecting it.
The Dictynoidea or dictynoids are a group of araneomorph spiders that have been treated as a superfamily. The composition of the group has varied. Phylogenetic studies in the 21st century have failed to confirm the monophyly of the dictynoids as originally defined.
The Haplogynae or haplogynes are one of the two main groups into which araneomorph spiders have traditionally been divided, the other being the Entelegynae. Morphological phylogenetic studies suggested that the Haplogynae formed a clade; more recent molecular phylogenetic studies refute this, although many of the ecribellate haplogynes do appear to form a clade, Synspermiata.
The Entelegynae or entelegynes are a subgroup of araneomorph spiders, the largest of the two main groups into which the araneomorphs were traditionally divided. Females have a genital plate (epigynum) and a "flow through" fertilization system; males have complex palpal bulbs. Molecular phylogenetic studies have supported the monophyly of Entelegynae.
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.
The anatomy of spiders includes many characteristics shared with other arachnids. These characteristics include bodies divided into two tagmata, eight jointed legs, no wings or antennae, the presence of chelicerae and pedipalps, simple eyes, and an exoskeleton, which is periodically shed.
Saltonia is a monotypic genus of North American cribellate araneomorph spiders in the family Dictynidae containing the single species, Saltonia incerta. It was first described by R. V. Chamberlin & Wilton Ivie in 1942, and has only been found in United States. Originally placed with the funnel weavers, it was moved to the Dictynidae in 1967.
This glossary describes the terms used in formal descriptions of spiders; where applicable these terms are used in describing other arachnids.
Orbiculariae is a potential clade of araneomorph spiders, uniting two groups that make orb webs. Phylogenetic analyses based on morphological characters have generally recovered this clade; analyses based on DNA have regularly concluded that the group is not monophyletic. The issue relates to the origin of orb webs: whether they evolved early in the evolutionary history of entelegyne spiders, with many groups subsequently losing the ability to make orb webs, or whether they evolved later, with fewer groups having lost this ability. As of September 2018, the weight of the evidence strongly favours the non-monophyly of "Orbiculariae" and hence the early evolution of orb webs, followed by multiple changes and losses.
The RTA clade is a clade of araneomorph spiders, united by the possession of a retrolateral tibial apophysis – a backward-facing projection on the tibia of the male pedipalp. The clade contains over 21,000 species, almost half the current total of about 46,000 known species of spider. Most of the members of the clade are wanderers and do not build webs. Despite making up approximately half of all modern spider diversity, there are no unambiguous records of the group from the Mesozoic and molecular clock evidence suggests that the group began to diversify during the Late Cretaceous.
Zorodictyna is a genus of spiders in the family Udubidae native to Madagascar. It has been described as an intermediate genus between Zoropsidae and Dictynidae, though it is now placed in Udubidae. This genus was originally placed in the family Zoropsidae, but it has been reassigned several times since. In 1967, Lehtinen moved it to Miturgidae. In 1999, it was moved back to Zoropsidae, and in 2015, it was moved to Udubidae.
