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 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.
In 1999, a phylogenetic study found a clade called "agelenoids" consisting of members of the families Agelenidae, Amphinectidae (now included in Desidae) and Desidae. [1] A 2005 study did not confirm this grouping, instead placing these three families plus Dictynidae in a clade called the "fused cribellar clade". [2] The Desidae have also been placed in the Dictynoidea. [3] In 2014, a cladogram produced in a study of dionychan spiders placed members of the families Amaurobiidae and Cycloctenidae in a clade with members of Agelenidae, Amphinectidae (now Desidae) and Desidae, as sister to the rest of the large RTA Clade. (Amaurobiidae, represented by the genera Pimus and Macrobunus , was not monophyletic in this study.) Shading marks families once considered agelenoids. [4]
| RTA clade |
| |||||||||||||||||||||||||||||||||||||||
A 2017 study also did not support the Agelenoidea, but placed the two families previously included in this group in a more widely defined "marronoid clade", comprising Amaurobiidae, Agelenidae, Cybaeidae, Cycloctenidae, Desidae, Dictynidae, Hahniidae, Stiphidiidae and Toxopidae, with Agelenidae and Desidae quite far apart. [5]
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.
Norman Ira Platnick was an American biological systematist and arachnologist. At the time of his death, he was a professor emeritus of the Richard Gilder Graduate School and Peter J. Solomon Family Curator Emeritus of the invertebrate zoology department of the American Museum of Natural History. A 1973 Ph.D. recipient at Harvard University, Platnick described over 1,800 species of spiders from around the world, making him the second most prolific spider taxonomist in history, behind only Eugène Simon. Until 2014 he was also the maintainer of the World Spider Catalog, a website formerly hosted by the AMNH which tracks the arachnology literature, and attempts to maintain a comprehensive list, sorted taxonomically, of every species of spider which has been formally described. In 2007 he received the International Society of Arachnology's Bonnet award, named for Pierre Bonnet, in recognition of his work on the catalog.
Cribellum literally means "little sieve", and in biology the term generally applies to anatomical structures in the form of tiny perforated plates.
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.
The Micropholcommatinae are a subfamily of araneomorph spiders in the family Anapidae. They were previously treated as the family Micropholcommatidae. Micropholcommatins are extremely small, with body lengths typically between 0.5 and 2 mm. They are usually found among leaf litter or moss.
The Dionycha are a clade of spiders (Araneomorphae:Entelegynae), characterized by the possession of two tarsal claws with tufts of hairs (setae) beside them, which produce strong adhesion, enabling some species to climb glass. The circumscription of the group has varied widely; a 2021 analysis resulted in about 20 families, including Salticidae, Gnaphosidae, and Clubionidae.
Lycosoidea is a clade or superfamily of araneomorph spiders. The traditional circumscription was based on a feature of the eyes. The tapetum is a reflective layer at the back of the eye, thought to increase sensitivity in low light levels. Lycosoids were then defined by having a "grate-shaped" tapetum. Research from the late 1990s onwards suggests that this feature has evolved more than once, possibly as many as five times, so that the original Lycosoidea is paraphyletic. Studies published in 2014 and 2015 suggest that a smaller group of families does form a clade.
The Dysderoidea are a clade or superfamily of araneomorph spiders. The monophyly of the group, initially consisting of the four families Dysderidae, Oonopidae, Orsolobidae and Segestriidae, has consistently been recovered in phylogenetic studies. In 2014, a new family, Trogloraptoridae, was created for a recently discovered species Trogloraptor marchingtoni. It was suggested that Trogloraptoridae may be the most basal member of the Dysderoidea clade. However, a later study found that Trogloraptoridae was placed outside the Dysderoidea and concluded that it was not part of this clade.
The Eresoidea or eresoids are a group of araneomorph spiders that have been treated as a superfamily. As usually circumscribed, the group contains three families: Eresidae, Hersiliidae and Oecobiidae. Studies and reviews based on morphology suggested the monophyly of the group; more recent gene-based studies have found the Eresidae and Oecobiidae to fall into different clades, placing doubt on the acceptability of the taxon. Some researchers have grouped Hersiliidae and Oecobiidae into the separate superfamily Oecobioidea, a conclusion supported in a 2017 study, which does not support Eresoidea.
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 Titanoecoidea or titanoecoids are a proposed taxon of araneomorph spiders at the superfamily rank. The taxon contains two families of spiders, Phyxelididae and Titanoecidae. Although some phylogenetic studies have shown these two families to form a clade, other studies have not, placing Titanoecidae outside the RTA clade while Phyxelididae is placed inside it. A 2011 classification of spider families leaves both Phyxelididae and Titanoecidae outside the RTA clade as "unplaced non-Orbiculariae families". The status of the group remains unclear as of December 2015.
The Austrochiloidea or austrochiloids are a group of araneomorph spiders, treated as a superfamily. The taxon contains two families of eight-eyed spiders:
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.
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.
Udubidae is a family of araneomorph spiders, most of whose members were formerly placed in the family Zorocratidae, which is no longer accepted.
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.
Campostichomma is a genus of spiders in the family Udubidae native to Sri Lanka. Many of its species were moved to either Griswoldia or Devendra. This genus was originally placed in the family Agelenidae. It was moved to Miturgidae in 1967, to Zoropsidae in 1999, then to Udubidae in 2015.
Synspermiata is a clade of araneomorph spiders, comprising most of the former "haplogynes". They are united by having simpler genitalia than other araneomorph spiders, lacking a cribellum, and sharing an evolutionary history of synspermia – a particular way in which spermatozoa are grouped together when transferred to the female.