# Bipectina > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Bipectina > Markdown URL: https://mediated.wiki/source/Bipectina.md > Source: https://en.wikipedia.org/wiki/Bipectina > Source revision: 1346201796 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) {{Short description|Clade of spiders}} {{Use dmy dates|cs1-dates=ly|date=June 2020}} {{Automatic taxobox |image = Dipluridae - Diplura fasciata.JPG |image_caption = ''[Diplura lineata](/source/Diplura_lineata)'', a member of the family [Dipluridae](/source/Dipluridae) |image2 = PSM V38 D203 Section view of the curved burrow of stothis astuta.jpg |image2_caption = Burrow of ''[Trichopelma astuta](/source/Trichopelma_astuta)'', a member of the family [Theraphosidae](/source/Theraphosidae) |taxon = Bipectina |authority = [Goloboff](/source/Pablo_Augusto_Goloboff), 1993 |subdivision_ranks = Families |subdivision = See text. }} '''Bipectina''' is a [clade](/source/clade) of [avicularioid](/source/Avicularioidea) [mygalomorph spiders](/source/Mygalomorphae) first proposed by [Pablo A. Goloboff](/source/Pablo_A._Goloboff) in 1993, based on a morphological [cladistic](/source/Cladistics) 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](/source/Glossary_of_spider_terms) 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](/source/Phylogenetics) study in 2020 upheld the [monophyly](/source/monophyly) of the clade, which contained 19 of the 25 accepted families of the Avicularioidea. The majority of [extant](/source/Extant_taxon) members of the Bipectina clade live in a burrow with one or more trapdoors, many adding radial alarm threads that alert them to the presence of prey. Others have reverted to using various kinds of web, as the earliest avicularioids are believed to have done, or have lost trapdoors, living in open burrows. ==Taxonomy== The clade Bipectina was first proposed by [Pablo A. Goloboff](/source/Pablo_A._Goloboff) in 1993, based on a purely morphological [cladistic](/source/Cladistics) analysis. One feature used in defining the clade was the bipectinate superior [tarsal claws](/source/Glossary_of_spider_terms) of the legs of both sexes (i.e. the claws had two rows of teeth). Females in the clade also had [pedipalps](/source/Glossary_of_spider_terms) in which their usual single rows of teeth were markedly displaced to the [prolateral](/source/Glossary_of_spider_terms) side of the claw. The clade was supported by most subsequent analyses, including those that included molecular evidence, although with different family compositions. ===Phylogeny=== The preferred [cladogram](/source/cladogram) from a 2020 phylogenetic study of the Mygalomorphae is shown below. Bipectina was resolved as a derived clade containing the majority of families of the Avicularioidea (19 out of 25). Some nodes within the clade had lower support (marked ♦ below), but the clade as a whole was well supported. {{clade |label1=[Avicularioidea](/source/Avicularioidea) |1={{clade |1=Basal families (6)|state1=double |label2=Bipectina |2={{clade |1=[Paratropididae](/source/Paratropididae) |2={{clade |label1=♦|style1=text-align:right |1={{clade |label1=♦|style1=text-align:right |1={{clade |1=[Stasimopidae](/source/Stasimopidae) |label2=Venom Clade |2={{clade |1=[Atracidae](/source/Atracidae) |2=[Actinopodidae](/source/Actinopodidae) }} }} |label2=[Domiothelina](/source/Domiothelina) |2={{clade |1=[Halonoproctidae](/source/Halonoproctidae) |2={{clade |1=[Migidae](/source/Migidae) |2={{clade |1=[Idiopidae](/source/Idiopidae) |2={{clade |1=[Ctenizidae](/source/Ctenizidae) |2=[Euctenizidae](/source/Euctenizidae) }} }} }} }} }} |label2=[Crassitarsae](/source/Crassitarsae) ♦ |2={{clade |label1=[Theraphosoidina](/source/Theraphosoidina) |1={{clade |1=[Bemmeridae](/source/Bemmeridae) |2={{clade |1=[Barychelidae](/source/Barychelidae) |2=[Theraphosidae](/source/Theraphosidae) }} }} |label2="[Nemesioidina](/source/Nemesioidina)" |2={{clade |1=[Nemesiidae](/source/Nemesiidae) |2={{clade |1=[Pycnothelidae](/source/Pycnothelidae) |2={{clade |1={{clade |1=[Dipluridae](/source/Dipluridae) |2=[Cyrtaucheniidae](/source/Cyrtaucheniidae) }} |2={{clade |1=[Anamidae](/source/Anamidae) |2={{clade |1=[Entypesidae](/source/Entypesidae) |2=[Microstigmatidae](/source/Microstigmatidae) }} }} }} }} }} }} }} }} }} }} Bipectina is estimated to have diverged from its sister (the small family [Macrothelidae](/source/Macrothelidae)) around 179–162 [Ma](/source/Year) (roughly the middle of the [Jurassic](/source/Jurassic)), possibly in Africa. The ancestor of the Avicularioidea probably used a sheet web to aid in prey capture. The status of the ancestor of Bipectina is not entirely clear, but the majority of current members of the Bipectina clade have a burrow with one or more trapdoors and radial alarm threads. Trapdoors have been shown to reduce foraging efficiency, but may serve as protection from predators or adverse environmental factors. Reduced selection pressure may explain why some members of the clade have lost trapdoors. Others have reverted to using some form of web in prey capture. ===Families=== According to Opatova et al. (2020), the clade includes the following families, some of which were first described at this rank in their study: {{Div col|colwidth=15em}} *[Actinopodidae](/source/Actinopodidae) *[Anamidae](/source/Anamidae) *[Atracidae](/source/Atracidae) *[Barychelidae](/source/Barychelidae) *[Bemmeridae](/source/Bemmeridae) *[Ctenizidae](/source/Ctenizidae) *[Cyrtaucheniidae](/source/Cyrtaucheniidae) *[Dipluridae](/source/Dipluridae) *[Entypesidae](/source/Entypesidae) *[Euctenizidae](/source/Euctenizidae) *[Halonoproctidae](/source/Halonoproctidae) *[Idiopidae](/source/Idiopidae) *[Microstigmatidae](/source/Microstigmatidae) *[Migidae](/source/Migidae) *[Nemesiidae](/source/Nemesiidae) *[Paratropididae](/source/Paratropididae) *[Pycnothelidae](/source/Pycnothelidae) *[Stasimopidae](/source/Stasimopidae) *[Theraphosidae](/source/Theraphosidae) {{Div col end}} ==References== {{Reflist|refs= {{Citation |last1=Bond |first1=Jason E. |last2=Garrison |first2=Nicole L. |last3=Hamilton |first3=Chris A. |last4=Godwin |first4=Rebecca L. |last5=Hedin |first5=Marshal |last6=Agnarsson |first6=Ingi |date=2014 |title=Phylogenomics Resolves a Spider Backbone Phylogeny and Rejects a Prevailing Paradigm for Orb Web Evolution |journal=Current Biology |volume=24 |issue=15 |pages=1765–1771 |doi=10.1016/j.cub.2014.06.034 |pmid=25042592 |bibcode=2014CBio...24.1765B |name-list-style=amp |doi-access=free }} {{Citation |last1=Bond |first1=Jason E. |last2=Hendrixson |first2=Brent E. |last3=Hamilton |first3=Chris A. |last4=Hedin |first4=Marshal |date=2012 |title=A Reconsideration of the Classification of the Spider Infraorder Mygalomorphae (Arachnida: Araneae) Based on Three Nuclear Genes and Morphology |journal=PLOS ONE |volume=7 |issue=6 |article-number=e38753 |doi=10.1371/journal.pone.0038753 |pmid=22723885 |pmc=3378619 |bibcode=2012PLoSO...738753B |name-list-style=amp |doi-access=free }} {{Citation |last1=Goloboff |first1=Pablo A. |date=1993 |title=A Reanalysis of Mygalomorph Spider Families (Araneae) |journal=American Museum Novitates |issue=3056 |hdl=2246/5017 |url=http://hdl.handle.net/2246/5017 |access-date=2020-07-20 }} {{Citation |last1=Hedin |first1=Marshal |last2=Bond |first2=Jason E. |date=2006 |title=Molecular phylogenetics of the spider infraorder Mygalomorphae using nuclear rRNA genes (18S and 28S): Conflict and agreement with the current system of classification |journal=Molecular Phylogenetics and Evolution |volume=41 |issue=2 |pages=454–471 |doi=10.1016/j.ympev.2006.05.017 |pmid=16815045 |bibcode=2006MolPE..41..454H |name-list-style=amp }} {{Citation |last1=Opatova |first1=Vera |last2=Hamilton |first2=Chris A. |last3=Hedin |first3=Marshal |last4=Montes De Oca |first4=Lauren |last5=Král |first5=Jiři |last6=Bond |first6=Jason E. |date=2019 |title=Phylogenetic Systematics and Evolution of the Spider Infraorder Mygalomorphae Using Genomic Scale Data |url=https://academic.oup.com/sysbio/article-abstract/69/4/671/5570998 |journal=Systematic Biology |volume=69 |issue=4 |pages=671–707 |doi=10.1093/sysbio/syz064|pmid=31841157 |doi-access=free |url-access=subscription }} }} {{Taxonbar|from1=Q97571511}} Category:Mygalomorphae Category:Taxa named by Pablo Augusto Goloboff --- Adapted from the Wikipedia article [Bipectina](https://en.wikipedia.org/wiki/Bipectina) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Bipectina?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.