Editing Xenarthra (section)

==Evolutionary relationships==
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[[File:Pink Fairy Armadillo (Chlamyphorus truncatus) (cropped).jpg|thumb|right|[[Pink fairy armadillo]] (''Chlamyphorus truncatus'')]]
Xenarthrans were previously classified alongside the [[pangolin]]s and [[aardvark]]s in the order '''Edentata''' (meaning toothless, because the members do not have incisors and lack, or have poorly developed, molars). Subsequently, Edentata was found to be a [[polyphyletic]] grouping whose New World and Old World taxa are unrelated, and it was split up to reflect their true [[phylogeny]]. Aardvarks and pangolins are now placed in individual orders, and the new order Xenarthra was erected to group the remaining families ([[Monophyly|which are all related]]). The morphology of xenarthrans generally suggests that the anteaters and sloths are more closely related to each other than either is to the armadillos, glyptodonts, and pampatheres; this idea is upheld by molecular studies. Since its conception, Xenarthra has increasingly come to be considered to be of a higher rank than 'order'; some authorities consider it to be a [[cohort (taxonomy)|cohort]], while others consider it to be a superorder.

Whatever the rank, Xenarthra is now generally considered to be divided into two orders:

* [[Cingulata]] (Latin, "the ones with belts/armor"), the armadillos and the extinct glyptodonts and pampatheres 
* [[Pilosa]] (Latin, "the ones with fur"), which is subdivided into: 
** [[Vermilingua]] ("worm-tongues"), the anteaters
** [[Folivora]] ("leaf-eaters"), the sloths (both tree sloths and the extinct ground sloths). Folivora is also called Tardigrada or Phyllophaga.<ref name="McKenna1997">{{cite book | last1 = McKenna | first1 = M.C. | last2 = Bell | first2 = S.K. | title = Classification of Mammals Above the Species Level | publisher = Columbia University Press | location = New York | isbn = 978-0-231-11013-6 | oclc = 37345734| year = 1997 | pages = 93}}</ref>

Their relationship to other placental mammals is obscure. Xenarthrans have been defined as most closely related to [[Afrotheria]]<ref>{{cite journal |doi=10.1101/gr.5918807 |title=Using genomic data to unravel the root of the placental mammal phylogeny |year=2007 |last1=Murphy |first1=W. J. |last2=Pringle |first2=T. H. |last3=Crider |first3=T. A. |last4=Springer |first4=M. S. |last5=Miller |first5=W. |journal=Genome Research |volume=17 |issue=4 |pages=413–21 |pmid=17322288 |pmc=1832088}}</ref> (in the group [[Atlantogenata]]), or to [[Boreoeutheria]] (in the group [[Exafroplacentalia]]), or to [[Epitheria]]<ref>{{cite journal |doi=10.1371/journal.pbio.0040091 |title=Retroposed Elements as Archives for the Evolutionary History of Placental Mammals |year=2006 |last1=Kriegs |first1=Jan Ole |last2=Churakov |first2=Gennady |last3=Kiefmann |first3=Martin |last4=Jordan |first4=Ursula |last5=Brosius |first5=Jürgen |last6=Schmitz |first6=Jürgen |journal=PLOS Biology |volume=4 |issue=4 |pages=e91 |pmid=16515367 |pmc=1395351 |doi-access=free }}</ref> (Afrotheria+Boreoeutheria, i.e. as a sister group to all other placental mammals). A comprehensive phylogeny by Goloboff et al.<ref>{{cite journal |doi=10.1111/j.1096-0031.2009.00255.x |title=Phylogenetic analysis of 73 060 taxa corroborates major eukaryotic groups |year=2009 |last1=Goloboff |first1=Pablo A. |last2=Catalano |first2=Santiago A. |last3=Marcos Mirande |first3=J. |last4=Szumik |first4=Claudia A. |last5=Salvador Arias |first5=J. |last6=Källersjö |first6=Mari |last7=Farris |first7=James S. |journal=Cladistics |volume=25 |issue=3 |pages=211–30|pmid=34879616 |s2cid=84401375 |doi-access=free |hdl=11336/78055 |hdl-access=free }}</ref> includes xenarthrans as a sister clade of [[Euarchontoglires]] within [[Boreoeutheria]] ([[Laurasiatheria]]+[[Euarchontoglires]]). Overall, studies using mitochondrial DNA have tended to group them as a sister clade to [[Ferungulata]] (carnivorans+ungulates+pholidotans), while studies using nuclear DNA have identified them as 1) a sister clade to Afrotheria, 2) a sister clade to all placentals ''except'' Afrotheria, or 3) a trichotomy (three-way split): Afrotheria, Xenarthra, and everything else (i.e. Boreoeutheria). Among studies that use physical characteristics rather than DNA to look at relationships, a large [[Phenomics|phenomic]] analysis of living and fossil mammals suggests placental mammals evolved shortly after the end of the Cretaceous, and first split into Xenarthra and Epitheria (all other placentals).<ref>{{Cite journal|last1=O'Leary|first1=Maureen A.|last2=Bloch|first2=Jonathan I.|last3=Flynn|first3=John J.|last4=Gaudin|first4=Timothy J.|last5=Giallombardo|first5=Andres|last6=Giannini|first6=Norberto P.|last7=Goldberg|first7=Suzann L.|last8=Kraatz|first8=Brian P.|last9=Luo|first9=Zhe-Xi|last10=Meng|first10=Jin|last11=Ni|first11=Xijun|date=2013-02-08|title=The placental mammal ancestor and the post-K-Pg radiation of placentals|journal=Science|volume=339|issue=6120|pages=662–667|doi=10.1126/science.1229237|issn=1095-9203|pmid=23393258|bibcode=2013Sci...339..662O|s2cid=206544776|hdl=11336/7302|hdl-access=free}}</ref>

===Phylogeny===
[[File:OrthoMaM v10b 2019 116genera circular tree.svg|thumb|upright=1.35|Phylogenetic position of xenarthrans (in orange) among placentals in a genus-level molecular phylogeny of 116 extant mammals inferred from the gene tree information of 14,509 [[Coding region|coding DNA sequences]].<ref name=Scornavacca2019>{{cite journal | vauthors = Scornavacca C, Belkhir K, Lopez J, Dernat R, Delsuc F, Douzery EJ, Ranwez V | title = OrthoMaM v10: Scaling-up orthologous coding sequence and exon alignments with more than one hundred mammalian genomes | journal = Molecular Biology and Evolution | volume = 36 | issue = 4 | pages = 861–862 | date = April 2019 | pmid = 30698751 | pmc = 6445298 | doi = 10.1093/molbev/msz015 }}</ref> The other major clades are colored: marsupials (magenta), afrotherians (red), laurasiatherians (green), and Euarchontoglires (blue).]]
Below is a recent simplified phylogeny of the xenarthran families based on Slater et al. (2016)<ref>Slater, G., Cui, P., Forasiepi, A. M., Lenz, D., Tsangaras, K., Voirin, B., ... & Greenwood, A. D. (2016). Evolutionary relationships among extinct and extant sloths: the evidence of mitogenomes and retroviruses. Genome Biology and Evolution, evw023.</ref> and Delsuc et al. (2016).<ref>Delsuc, F., Gibb, G. C., Kuch, M., Billet, G., Hautier, L., Southon, J., ... & Poinar, H. N. (2016). The phylogenetic affinities of the extinct glyptodonts. Current Biology, 26(4), R155-R156.</ref> The dagger symbol, "†", denotes extinct groups.
{{clade
|style=font-size:100%
|label1='''Xenarthra'''
|1={{clade
   |label1=[[Cingulata]]
   |1={{clade
      |label1=
      |1=[[Dasypodidae]]
      |label2=
      |2={{Clade
         |1=†[[Pampatheriidae]]
         |2=[[Chlamyphoridae]]
         }}
      }}
   |label2=[[Pilosa]]
   |2={{clade
      |label1=[[Anteater|Vermilingua]]
      |1={{clade
         |1=[[Cyclopedidae]]
         |2=[[Myrmecophagidae]]
         }}
      |label2=[[Sloth|Folivora]]
      |2={{clade
         |1={{Clade
             |1=†''[[Mylodontidae]]''
             |2={{Clade
               |2=†[[Megalonychidae]]
               |state2=double
               |1=[[Choloepodidae]] (two-toed sloths)
               }}
            }}
         |2={{Clade
            |1=[[Bradypodidae]] (three-toed sloths)
            |2=†[[Nothrotheriidae]]
            |3=†''[[Megatheriidae]]''
            }}
         }}
      }}
   }}
}}