Related Research Articles
Cybaeidae is a family of spiders first described by Nathan Banks in 1892. The diving bell spider or water spider Argyroneta aquatica was previously included in this family, but is now in the family Dictynidae.
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.
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 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 Palpimanoidea or palpimanoids, also known as assassin spiders, are a group of araneomorph spiders, originally treated as a superfamily. As with many such groups, its circumscription has varied. As of September 2018, the following five families were included:
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 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 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.
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:
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.
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.
Toxopidae is a small family of araneomorph spiders, first described in 1940. For many years it was sunk into Desidae as a subfamily, although doubts were expressed as to whether this was correct. A large-scale molecular phylogenetic study in 2016 led to the family being revived.
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.
References
- 1 2 Griswold, Charles E.; Coddington, Jonathan A.; Platnick, Norman I. & Forster, Raymond R. (1999), "Towards a Phylogeny of Entelegyne Spiders (Araneae, Araneomorphae, Entelegynae)", Journal of Arachnology, 27 (1): 53–63, JSTOR 3705965 , p. 60
- 1 2 Coddington, Jonathan A. & Levi, Herbert W. (1991), "Systematics and evolution of spiders (Araneae)", Annual Review of Ecology and Systematics, 22: 565–592, doi:10.1146/annurev.es.22.110191.003025, JSTOR 2097274, S2CID 55647804
- ↑ Coddington, Jonathan A. (2005), "Phylogeny and classification of spiders" (PDF), in Ubick, D.; Paquin, P.; Cushing, P.E. & Roth, V. (eds.), Spiders of North America: an identification manual, American Arachnological Society, pp. 18–24, retrieved 2015-09-24
- ↑ Blackledge, Todd A.; Scharff, Nikolaj; Coddington, Jonathan A.; Szüts, Tamas; Wenzel, John W.; Hayashi, Cheryl Y. & Agnarsson, Ingi (2009), "Reconstructing web evolution and spider diversification in the molecular era", Proceedings of the National Academy of Sciences, 106 (13): 5229–5234, doi: 10.1073/pnas.0901377106 , PMC 2656561 , PMID 19289848
- ↑ Wolff, Jonas O.; Nentwig, Wolfgang & Gorb, Stanislav N. (2013), "The Great Silk Alternative: Multiple Co-Evolution of Web Loss and Sticky Hairs in Spiders", PLOS ONE, 8 (5): e62682, doi: 10.1371/journal.pone.0062682 , PMC 3641104 , PMID 23650526 , based on Nentwig, Wolfgang, ed. (2013), "Appendix : Spider Phylogeny" (PDF), Spider Ecophysiology, Springer, ISBN 978-3-642-33988-2 , retrieved 2015-11-03
- ↑ Wheeler, Ward C.; Coddington, Jonathan A.; Crowley, Louise M.; Dimitrov, Dimitar; Goloboff, Pablo A.; Griswold, Charles E.; Hormiga, Gustavo; Prendini, Lorenzo; Ramírez, Martín J.; Sierwald, Petra; Almeida-Silva, Lina; Alvarez-Padilla, Fernando; Arnedo, Miquel A.; Benavides Silva, Ligia R.; Benjamin, Suresh P.; Bond, Jason E.; Grismado, Cristian J.; Hasan, Emile; Hedin, Marshal; Izquierdo, Matías A.; Labarque, Facundo M.; Ledford, Joel; Lopardo, Lara; Maddison, Wayne P.; Miller, Jeremy A.; Piacentini, Luis N.; Platnick, Norman I.; Polotow, Daniele; Silva-Dávila, Diana; Scharff, Nikolaj; Szűts, Tamás; Ubick, Darrell; Vink, Cor J.; Wood, Hannah M. & Zhang, Junxia (2017) [published online 2016], "The spider tree of life: phylogeny of Araneae based on target-gene analyses from an extensive taxon sampling", Cladistics, 33 (6): 574–616, doi: 10.1111/cla.12182 , PMID 34724759, S2CID 35535038
- ↑ Dunlop, Jason A. & Penney, David (2011), "Order Araneae Clerck, 1757" (PDF), in Zhang, Z.-Q. (ed.), Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness, Zootaxa, Auckland, New Zealand: Magnolia Press, ISBN 978-1-86977-850-7 , retrieved 2015-10-31