# Xenarthra

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Superorder of mammals including anteaters, sloths, and armadillos

Xenarthrans Temporal range: Late Paleocene –Recent, 60–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N Clockwise from upper left: the giant ground sloth Megatherium, giant anteater, two-toed sloth, nine-banded armadillo Scientific classification Kingdom: Animalia Phylum: Chordata Class: Mammalia Infraclass: Placentalia Magnorder: Atlantogenata Superorder: Xenarthra Cope, 1889 Orders and suborders Order Cingulata (armadillos) Order Pilosa Suborder Folivora (sloths) Suborder Vermilingua (anteaters) See text for more details Blue: Sloth, Red: anteater, Yellow: Armadillo.

**Xenarthra** ([/zɛˈnɑːrθrə/](https://en.wikipedia.org/wiki/Help:IPA/English); from [Ancient Greek](/source/Ancient_Greek) [ξένος](https://en.wiktionary.org/wiki/%CE%BE%CE%AD%CE%BD%CE%BF%CF%82) (*xénos*), meaning "strange, foreign", and [ἄρθρον](https://en.wiktionary.org/wiki/%E1%BC%84%CF%81%CE%B8%CF%81%CE%BF%CE%BD) (*árthron*), meaning "joint") is a [superorder](/source/Order_(biology)) and major [clade](/source/Clade) of [placental mammals](/source/Placentalia) native to the [Americas](/source/Americas). There are 31 living species: the [anteaters](/source/Anteater), tree [sloths](/source/Sloth), and [armadillos](/source/Armadillo).[1] Extinct xenarthrans include the [glyptodonts](/source/Glyptodont), [pampatheres](/source/Pampatheriidae) and [ground sloths](/source/Ground_sloth), with some glyptodonts and ground sloths reaching sizes of several tonnes, much larger than any living xenarthran. Xenarthrans originated in South America during the late [Paleocene](/source/Paleocene) about 60 million years ago.[2] They evolved and diversified extensively in [South America](/source/South_America) during the continent's long period of isolation in the early to mid [Cenozoic](/source/Cenozoic) Era. They spread to the [Antilles](/source/Antilles) by the early [Miocene](/source/Miocene) and, starting about 10 million years ago, spread to [Central](/source/Central_America) and [North America](/source/North_America) as part of the [Great American Interchange](/source/Great_American_Interchange).[3] Nearly all of the formerly abundant [megafaunal](/source/Megafauna) xenarthrans became extinct at the end of the [Pleistocene](/source/Pleistocene) as part of the [end-Pleistocene extinction event](/source/Late_Pleistocene_extinctions).

## Characteristics

Xenarthrans share several characteristics that are not present in other placental mammals. The name Xenarthra derives from the two [ancient Greek](/source/Ancient_Greek) words [ξένος](https://en.wiktionary.org/wiki/%CE%BE%CE%AD%CE%BD%CE%BF%CF%82#Ancient_Greek) (*xénos*), meaning "strange, unusual", and [ἄρθρον](https://en.wiktionary.org/wiki/%E1%BC%84%CF%81%CE%B8%CF%81%CE%BF%CE%BD#Ancient_Greek) (*árthron*), meaning "joint",[4][5] and refers to their vertebral joints, which have extra articulations that are unlike other mammals. The [ischium](/source/Ischium) of the pelvis is also fused to the [sacrum](/source/Sacrum) of the spine.[6] Xenarthran limb bones are typically robust, with large processes for muscle attachment. Relative to their body size, living xenarthrans are extremely strong.[7] Their limb bone structures are unusual. They have single-color vision. The teeth of xenarthrans are unique. Xenarthrans are also often considered to be among the most primitive of placental mammals. Females show no clear distinction between the uterus and vagina, and males have [testicles](/source/Testicle) inside the body, which are located between the bladder and the rectum.[8] Xenarthrans have the lowest [metabolic rates](/source/Basal_metabolic_rate) among [therians](/source/Theria).[9][10]

### Dentition

The teeth of xenarthrans differ from all other mammals. The dentition of most species is either significantly reduced and highly modified, or absent.[11] With the single exception of *Dasypus* armadillos and their ancestral genus *Propraopus*, xenarthrans do not have a [milk dentition](/source/Baby_teeth). They have a single set of teeth through their lives; these teeth have no functional [enamel](/source/Tooth_enamel), and usually there are few or no teeth in the front of the mouth and the rear teeth all look alike. As a result, it is impossible to define Xenarthra as having incisors, canines, premolars, or molars. Since most mammals are classified by their teeth, it has been difficult to determine their relationships to other mammals. Xenarthrans may have evolved from ancestors that had already lost basic mammalian dental features like tooth enamel and a crown with cusps; reduced, highly simplified teeth are usually found in mammals that feed by licking up social insects. Several groups of xenarthrans did evolve [cheek teeth](/source/Cheek_teeth) to chew plants, but since they lacked enamel, patterns of harder and softer [dentine](/source/Dentin) created grinding surfaces. Dentine is less resistant to wear than the enamel-cusped teeth of other mammals, and xenarthrans developed open-rooted teeth that grow continuously.[12] Currently, no living or extinct xenarthrans have been found to have the standard mammalian [dental formula](/source/Dental_formula) or crown morphology derived from the ancient [tribosphenic](/source/Tribosphenic_molar) pattern.[13]

### Spine

The name Xenarthra, which means "strange joints", was chosen because the vertebral joints of members of the group have extra articulations of a type unlike any other mammals. This trait is referred to as "xenarthry". (Tree sloths lost these articulations to increase the flexibility of their spines, but their fossil ancestors had xenarthrous joints.) Additional points of articulation between vertebrae [strengthen and stiffen the spine](/source/Thor's_hero_shrew), an adaptation developed in different ways in various groups of mammals that dig for food. Xenarthrans also tend to have different numbers of vertebrae than other mammals; sloths have a reduced number of lumbar vertebrae with either more or fewer [cervical vertebrae](/source/Cervical_vertebrae) than most mammals, while cingulates have neck vertebrae fused into a cervical tube, with glyptodonts fusing [thoracic](/source/Thorax) and [lumbar](/source/Lumbar) vertebrae as well.[1]

### Vision

Xenarthrans have been determined to have single-color vision. [PCR](/source/Polymerase_chain_reaction) analysis determined that a mutation in a stem xenarthran led to long-wavelength sensitive-cone (LWS) [monochromacy](/source/Monochromacy) (single color vision), common in nocturnal, aquatic and subterranean mammals.[14] Further losses led to rod monochromacy in a stem [cingulate](/source/Cingulata) and a stem [pilosan](/source/Pilosa), pointing to a subterranean ancestry; the ancestors of Xenarthra had the reduced eyesight characteristic of vertebrates that live underground.[14] Some authorities state that xenarthrans lack a functional [pineal gland](/source/Pineal_gland); pineal activity is related to the perception of light.[15]

### Metabolism

Living xenarthrans have the lowest metabolic rates among [therians](/source/Theria).[9][16] Paleoburrows have been discovered which are up to 1.5 m (5 ft) wide and 40 m (130 ft) long, with claw marks from excavation referred to the ground sloths *Glossotherium* or *Scelidotherium*. Remains of ground sloths (*Mylodon* and others) in caves are particularly common in colder parts of their range, suggesting ground sloths may have used burrows and caves to help regulate their body temperature. Analysis of the fossil South American [Lujan](/source/Luj%C3%A1n_River) fauna suggests far more large herbivorous mammals were present than similar contemporary environments can support. As most large Lujan herbivores were xenarthrans, low metabolic rate may be a feature of the entire clade, allowing relatively low-resource scrublands to support large numbers of huge animals. Faunal analysis also shows far fewer large predators in pre-[GABI](/source/Great_American_Interchange) South American faunas than would be expected based on current faunas in similar environments. This suggests other factors than predation controlled the numbers of xenarthrans. South America had no placental predatory mammals until the Pleistocene, and xenarthran large-mammal faunas may have been vulnerable to many factors including a rise in numbers of mammalian predators, resource use by spreading North American herbivores with faster metabolisms and higher food requirements, and climate change.[12]

## Relationships to other mammals

[Pink fairy armadillo](/source/Pink_fairy_armadillo) (*Chlamyphorus truncatus*)

Xenarthrans were previously classified alongside the [pangolins](/source/Pangolin) and [aardvarks](/source/Aardvark) 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](/source/Polyphyletic) grouping whose New World and Old World taxa are unrelated, and it was split up to reflect their true [phylogeny](/source/Phylogeny). Aardvarks and pangolins are now placed in individual orders, and the new order Xenarthra was erected to group the remaining families ([which are all related](/source/Monophyly)). 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](/source/Cohort_(taxonomy)), while others consider it to be a superorder.

Whatever the rank, Xenarthra is now generally considered to be divided into two orders:[17]

- [Cingulata](/source/Cingulata) (Latin, "the ones with belts/armor"), the armadillos and the extinct glyptodonts and pampatheres

- [Pilosa](/source/Pilosa) (Latin, "the ones with fur"), which is subdivided into: - [Vermilingua](/source/Vermilingua) ("worm-tongues"), the anteaters - [Folivora](/source/Folivora) ("leaf-eaters"), the sloths (both tree sloths and the extinct ground sloths). Folivora is also called Tardigrada or Phyllophaga.

Their relationship to other placental mammals is obscure. Xenarthrans have been defined as most closely related to [Afrotheria](/source/Afrotheria)[18] (in the group [Atlantogenata](/source/Atlantogenata)), or to [Boreoeutheria](/source/Boreoeutheria) (in the group [Exafroplacentalia](/source/Exafroplacentalia)), or to [Epitheria](/source/Epitheria)[19] (Afrotheria+Boreoeutheria, i.e. as a sister group to all other placental mammals). A comprehensive phylogeny by Goloboff et al.[20] includes xenarthrans as a sister clade of [Euarchontoglires](/source/Euarchontoglires) within [Boreoeutheria](/source/Boreoeutheria) ([Laurasiatheria](/source/Laurasiatheria)+[Euarchontoglires](/source/Euarchontoglires)). Overall, studies using mitochondrial DNA have tended to group them as a sister clade to [Ferungulata](/source/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 [phenomic](/source/Phenomics) 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).[21]

### Phylogeny

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 DNA sequences](/source/Coding_region).[22] 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)[23] and Delsuc et al. (2016).[24] The dagger symbol, "†", denotes extinct groups.

Xenarthra Cingulata Dasypodidae †Pampatheriidae Chlamyphoridae Pilosa Vermilingua Cyclopedidae Myrmecophagidae Folivora †Mylodontidae Choloepodidae (two-toed sloths) †Megalonychidae Bradypodidae (three-toed sloths) †Nothrotheriidae †Megatheriidae

## Evolution

It has been suggested that the last common ancestor of xenarthrans was [myrmecophagous](/source/Myrmecophagous) (feeding on ants and termites), with digging and possibly climbing capabilities. The oldest fossils of xenarthrans are isolated remains known from the [Itaboraí Formation](/source/Itabora%C3%AD_Formation) of Brazil, dating to the early [Eocene](/source/Eocene) or possibly latest [Paleocene](/source/Paleocene), which already includes remains recognisable as armadillos. Most Eocene remains of xenarthrans are attributed to armadillos. The oldest known sloth, *[Pseudoglyptodon](/source/Pseudoglyptodon)* is known from the late Eocene, with remains known from across South America. The oldest fossils of anteaters date to the [Miocene](/source/Miocene) epoch.[25]

## Classification

The name Pan-Xenarthra is used for the [total group](/source/Total_group), with the alternative Americatheria having been abandoned.[26] However no unambiguous [stem group](/source/Stem_group) taxa have been identified.

[Giant armadillo](/source/Giant_armadillo)

Skeleton of *[Glyptodon](/source/Glyptodon),* an extinct [glyptodont](/source/Glyptodont) related to living armadillos

[Nine-banded armadillo](/source/Nine-banded_armadillo)

[Brown-throated sloth](/source/Brown-throated_sloth)

[Hoffmann's two-toed sloth](/source/Hoffmann's_two-toed_sloth)

[Giant anteater](/source/Giant_anteater)

**XENARTHRA**

- Order [Cingulata](/source/Cingulata) - Family [Chlamyphoridae](/source/Chlamyphoridae): armadillos and [glyptodonts](/source/Glyptodontinae) - [Greater fairy armadillo](/source/Greater_fairy_armadillo), *Calyptophractus retusus* - [Pink fairy armadillo](/source/Pink_fairy_armadillo), *Chlamyphorus truncatus* - [Northern naked-tailed armadillo](/source/Northern_naked-tailed_armadillo), *Cabassous centralis* - [Chacoan naked-tailed armadillo](/source/Chacoan_naked-tailed_armadillo), *Cabassous chacoensis* - [Southern naked-tailed armadillo](/source/Southern_naked-tailed_armadillo), *Cabassous unicinctus* - [Greater naked-tailed armadillo](/source/Greater_naked-tailed_armadillo), *Cabassous tatouay* - [Screaming hairy armadillo](/source/Screaming_hairy_armadillo), *Chaetophractus vellerosus* - [Big hairy armadillo](/source/Big_hairy_armadillo), *Chaetophractus villosus* - [Andean hairy armadillo](/source/Andean_hairy_armadillo), *Chaetophractus nationi* - [Six-banded armadillo](/source/Six-banded_armadillo) or yellow armadillo, *Euphractus sexcinctus* - [Giant armadillo](/source/Giant_armadillo), *Priodontes maximus* - [Southern three-banded armadillo](/source/Southern_three-banded_armadillo), *Tolypeutes matacus* - [Brazilian three-banded armadillo](/source/Brazilian_three-banded_armadillo), *Tolypeutes tricinctus* - [Pichi](/source/Pichi) or dwarf armadillo, *Zaedyus pichiy* - Subfamily †[Glyptodontinae](/source/Glyptodontinae): glyptodonts - Family [Dasypodidae](/source/Dasypodidae): long-nosed armadillos - [Nine-banded armadillo](/source/Nine-banded_armadillo) or long-nosed armadillo, *Dasypus novemcinctus* - [Seven-banded armadillo](/source/Seven-banded_armadillo), *Dasypus septemcinctus* - [Southern long-nosed armadillo](/source/Southern_long-nosed_armadillo), *Dasypus hybridus* - [Llanos long-nosed armadillo](/source/Llanos_long-nosed_armadillo), *Dasypus sabanicola* - [Great long-nosed armadillo](/source/Great_long-nosed_armadillo), *Dasypus kappleri* - [Hairy long-nosed armadillo](/source/Hairy_long-nosed_armadillo), *Dasypus pilosus* - [Yepes's mulita](/source/Yepes's_mulita), *Dasypus yepesi* - Family †[Pampatheriidae](/source/Pampatheriidae): pampatheres

- Order [Pilosa](/source/Pilosa) - Suborder [Folivora](/source/Folivora): sloths - Family [Bradypodidae](/source/Bradypodidae): three-toed sloths - [Pygmy three-toed sloth](/source/Pygmy_three-toed_sloth), *Bradypus pygmaeus* - [Brown-throated three-toed sloth](/source/Brown-throated_three-toed_sloth), *Bradypus variegatus* - [Pale-throated three-toed sloth](/source/Pale-throated_three-toed_sloth), *Bradypus tridactylus* - [Maned three-toed sloth](/source/Maned_three-toed_sloth), *Bradypus torquatus* - Family †[Megalonychidae](/source/Megalonychidae): megalonychid ground sloths - Family †[Megatheriidae](/source/Megatheriidae): megatheriid ground sloths - Family †[Nothrotheriidae](/source/Nothrotheriidae): nothrotheriid ground sloths and aquatic sloths - Family [Choloepodidae](/source/Two-toed_sloth): two-toed sloths - [Hoffman's two-toed sloth](/source/Hoffman's_two-toed_sloth), *Choloepus hoffmanni* - [Linnaeus's two-toed sloth](/source/Linnaeus's_two-toed_sloth) or southern two-toed sloth, *Choloepus didactylus* - Family †[Mylodontidae](/source/Mylodontidae): mylodontid ground sloths - Suborder [Vermilingua](/source/Vermilingua): anteaters - Family [Cyclopedidae](/source/Cyclopedidae): silky anteaters - [Silky anteater](/source/Silky_anteater), *Cyclopes didactylus* - Family [Myrmecophagidae](/source/Myrmecophagidae): anteaters - [Giant anteater](/source/Giant_anteater), *Myrmecophaga tridactyla* - [Northern tamandua](/source/Northern_tamandua), *Tamandua mexicana* - [Southern tamandua](/source/Southern_tamandua), *Tamandua tetradactyla*

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1. ^ [***a***](#cite_ref-Emerling2015_14-0) [***b***](#cite_ref-Emerling2015_14-1) Emerling, Christopher A.; Springer, Mark S. (2015-02-07). ["Genomic evidence for rod monochromacy in sloths and armadillos suggests early subterranean history for Xenarthra"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4298209). *Proceedings of the Royal Society B: Biological Sciences*. **282** (1800) 20142192. [doi](/source/Doi_(identifier)):[10.1098/rspb.2014.2192](https://doi.org/10.1098%2Frspb.2014.2192). [ISSN](/source/ISSN_(identifier)) [0962-8452](https://search.worldcat.org/issn/0962-8452). [PMC](/source/PMC_(identifier)) [4298209](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4298209). [PMID](/source/PMID_(identifier)) [25540280](https://pubmed.ncbi.nlm.nih.gov/25540280).

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1. **[^](#cite_ref-McKenna1997_17-0)** McKenna, M.C.; Bell, S.K. (1997). *Classification of Mammals Above the Species Level*. New York: Columbia University Press. p. 93. [ISBN](/source/ISBN_(identifier)) [978-0-231-11013-6](https://en.wikipedia.org/wiki/Special:BookSources/978-0-231-11013-6). [OCLC](/source/OCLC_(identifier)) [37345734](https://search.worldcat.org/oclc/37345734).

1. **[^](#cite_ref-18)** Murphy, W. J.; Pringle, T. H.; Crider, T. A.; Springer, M. S.; Miller, W. (2007). ["Using genomic data to unravel the root of the placental mammal phylogeny"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1832088). *Genome Research*. **17** (4): 413–21. [doi](/source/Doi_(identifier)):[10.1101/gr.5918807](https://doi.org/10.1101%2Fgr.5918807). [PMC](/source/PMC_(identifier)) [1832088](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1832088). [PMID](/source/PMID_(identifier)) [17322288](https://pubmed.ncbi.nlm.nih.gov/17322288).

1. **[^](#cite_ref-19)** Kriegs, Jan Ole; Churakov, Gennady; Kiefmann, Martin; Jordan, Ursula; Brosius, Jürgen; Schmitz, Jürgen (2006). ["Retroposed Elements as Archives for the Evolutionary History of Placental Mammals"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1395351). *PLOS Biology*. **4** (4) e91. [doi](/source/Doi_(identifier)):[10.1371/journal.pbio.0040091](https://doi.org/10.1371%2Fjournal.pbio.0040091). [PMC](/source/PMC_(identifier)) [1395351](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1395351). [PMID](/source/PMID_(identifier)) [16515367](https://pubmed.ncbi.nlm.nih.gov/16515367).

1. **[^](#cite_ref-20)** Goloboff, Pablo A.; Catalano, Santiago A.; Marcos Mirande, J.; Szumik, Claudia A.; Salvador Arias, J.; Källersjö, Mari; Farris, James S. (2009). ["Phylogenetic analysis of 73 060 taxa corroborates major eukaryotic groups"](https://doi.org/10.1111%2Fj.1096-0031.2009.00255.x). *Cladistics*. **25** (3): 211–30. [Bibcode](/source/Bibcode_(identifier)):[2009Cladi..25..211G](https://ui.adsabs.harvard.edu/abs/2009Cladi..25..211G). [doi](/source/Doi_(identifier)):[10.1111/j.1096-0031.2009.00255.x](https://doi.org/10.1111%2Fj.1096-0031.2009.00255.x). [hdl](/source/Hdl_(identifier)):[11336/78055](https://hdl.handle.net/11336%2F78055). [PMID](/source/PMID_(identifier)) [34879616](https://pubmed.ncbi.nlm.nih.gov/34879616). [S2CID](/source/S2CID_(identifier)) [84401375](https://api.semanticscholar.org/CorpusID:84401375).

1. **[^](#cite_ref-21)** O'Leary, Maureen A.; Bloch, Jonathan I.; Flynn, John J.; Gaudin, Timothy J.; Giallombardo, Andres; Giannini, Norberto P.; Goldberg, Suzann L.; Kraatz, Brian P.; Luo, Zhe-Xi; Meng, Jin; Ni, Xijun (2013-02-08). "The placental mammal ancestor and the post-K-Pg radiation of placentals". *Science*. **339** (6120): 662–667. [Bibcode](/source/Bibcode_(identifier)):[2013Sci...339..662O](https://ui.adsabs.harvard.edu/abs/2013Sci...339..662O). [doi](/source/Doi_(identifier)):[10.1126/science.1229237](https://doi.org/10.1126%2Fscience.1229237). [hdl](/source/Hdl_(identifier)):[11336/7302](https://hdl.handle.net/11336%2F7302). [ISSN](/source/ISSN_(identifier)) [1095-9203](https://search.worldcat.org/issn/1095-9203). [PMID](/source/PMID_(identifier)) [23393258](https://pubmed.ncbi.nlm.nih.gov/23393258). [S2CID](/source/S2CID_(identifier)) [206544776](https://api.semanticscholar.org/CorpusID:206544776).

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## External links

Look up ***[xenarthra](https://en.wiktionary.org/wiki/Special:Search/xenarthra)*** in Wiktionary, the free dictionary.

[Wikispecies](/source/Wikispecies) has information related to ***[Xenarthra](https://species.wikimedia.org/wiki/Special:Search/Xenarthra)***.

Wikimedia Commons has media related to [Xenarthra](https://commons.wikimedia.org/wiki/Category:Xenarthra).

- Wildman, Derek E.; Chen, Caoyi; Erez, Offer; Grossman, Lawrence I.; Goodman, Morris; Romero, Roberto (2006). ["Evolution of the mammalian placenta revealed by phylogenetic analysis"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1413940). *Proceedings of the National Academy of Sciences*. **103** (9): 3203–3208. [Bibcode](/source/Bibcode_(identifier)):[2006PNAS..103.3203W](https://ui.adsabs.harvard.edu/abs/2006PNAS..103.3203W). [doi](/source/Doi_(identifier)):[10.1073/pnas.0511344103](https://doi.org/10.1073%2Fpnas.0511344103). [JSTOR](/source/JSTOR_(identifier)) [30048561](https://www.jstor.org/stable/30048561). [PMC](/source/PMC_(identifier)) [1413940](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1413940). [PMID](/source/PMID_(identifier)) [16492730](https://pubmed.ncbi.nlm.nih.gov/16492730).

- ["Armadillos: Biology, Ecology and Images"](https://armadillo-online.org/species.html). Armadillo Online. 1995. Retrieved 19 December 2017.

v t e Eutheria Kingdom: Animalia Phylum: Chordata Class: Mammalia Subclass: Theria Synapsida see Synapsida Cynodontia see Cynodontia Mammalia see Mammalia Eutheria see below↓ Eutheria Eutheria †Acristatherium? †Ambolestes? †Bayshinoryctes †Bobolestes? †Cokotherium? †Deltatherium †Durlstodon †Durlstotherium †Endotherium †Eomaia? †Hovurlestes †Hyotheridium? †Indoclemensia †Juramaia? †Microtherulum? †Montanalestes? †Murtoilestes? †Prokennalestes? †Sinodelphys? †Adapisoriculidae Adapisoriculus Afrodon Bustylus Deccanolestes? Garatherium Namibiodon Remiculus? Sahnitherium? Wyonycteris? †Asioryctitheria Asioryctes Bulaklestes Daulestes Kennalestes Sasayamamylos Uchkudukodon Ukhaatherium †Cimolestidae Aboletylestes Acmeodon Alveugena Ambilestes Avunculus Bagalestes Batodon? Betonnia Chacopterygus Cimolestes Didelphodus Gelastops Ilerdoryctes Maelestes? Naranius Pararyctes Procerberus Protentomodon Puercolestes Scollardius Tsaganius †Didymoconidae Archaeoryctes Ardynictis Didymoconus Hunanictis Kennatherium Zeuctherium †Horolodectidae Ferrequitherium Horolodectes †Leptictida Gypsonictopidae Gypsonictops Sikuomys Pseudorhyncocyonidae Diaphyodectes Leptictidium Phakodon Pseudorhyncocyon Leptictidae Amphigyion Blacktops Gallolestes Ictopidium Labes Lainodon Leptictis Leptonysson Megaleptictis Myrmecoboides Ongghonia Palaeictops Praolestes Prodiacodon Protictops Wania †Palaeoryctidae Aaptoryctes Aceroryctes Eoryctes Lainoryctes Nuryctes Ottoryctes Palaeoryctes Pinoryctes †Pantolesta Paroxyclaenidae Fratrodon Kopidodon Merialus Paraspaniella Paravulpavoides Paroxyclaenus Pugiodens Sororodon Spaniella Vulpavoides Welcommoides Pantolestidae Amaramnis Bessoecetor Bogdia Bouffinomus Buxolestes Chadronia Cryptopithecus Dulcidon Dyspterna Euhookeria Galethylax Gobipithecus Kiinkerishella Kochictis Oboia Pagonomus Palaeosinopa Paleotomus Pantolestes Thelysia Todralestes Pentacodontidae Aphronorus Bisonalveus Coriphagus Eurolestes Pentacodon †Taeniodonta Schowalteria Conoryctidae Conoryctella Conoryctes Huerfanodon Onychodectidae Onychodectes Stylinodontidae Ectoganus Psittacotherium Stylinodon Wortmania †Tillodontia Adapidium Azygonyx Basalina Benaius Chungchienia Dysnoetodon Esthonyx Franchaius Higotherium Interogale Kuanchuanius Lofochaius Megalesthonyx Meiostylodon Plesiesthonyx Plethorodon Simplodon Tillodon Trogosus Yuesthonyx †Zalambdalestidae Alymlestes Anchilestes Barunlestes Beleutinus Kulbeckia Prozalambdalestes Zalambdalestes Zhangolestes Zofialestes †Zhelestidae Alostera? Aspanlestes Avitotherium Azilestes? Borisodon Eoungulatum Eozhelestes Gallolestes Kharmerungulatum Khuduklestes? Lainodon Mistralestes? Oxlestes? Paranyctoides? Parazhelestes Sheikhdzheilia Sorlestes Valentinella? Zhalmousia Zhelestes †Pantodonta see Pantodonta Placentalia Afrotheria Boreoeutheria Xenarthra

v t e Extant mammal orders Kingdom Animalia Phylum Chordata Subphylum Vertebrata (unranked) Amniota Yinotheria Australosphenida Monotremata (platypuses and echidnas) Theria Metatheria (Marsupial inclusive) Ameridelphia Paucituberculata (shrew opossums) Didelphimorphia (opossums) Australidelphia Microbiotheria (monitos del monte) Notoryctemorphia (marsupial moles) Dasyuromorphia (quolls and dunnarts) Peramelemorphia (bilbies and bandicoots) Diprotodontia (kangaroos, koalas, and relatives) Eutheria (Placental inclusive) Atlantogenata Xenarthra Cingulata (armadillos) Pilosa (anteaters and sloths) Afrotheria Afrosoricida (tenrecs, golden moles, and otter shrews) Macroscelidea (elephant shrews) Tubulidentata (aardvarks) Hyracoidea (hyraxes) Proboscidea (elephants) Sirenia (dugongs and manatees) Boreoeutheria Laurasiatheria Eulipotyphla (hedgehogs, shrews, moles and relatives) Chiroptera (bats) Pholidota (pangolins) Carnivora (dogs, cats and relatives) Perissodactyla (horses, zebras, donkeys, rhinoceroses and tapirs) Artiodactyla (pigs, camels, hippos, deer, buffalo, gazelles, giraffes, whales, dolphins and relatives) Euarchontoglires Rodentia (rats, mice, guinea pigs, squirrels, beavers, chinchillas, porcupines, capybaras and relatives) Lagomorpha (rabbits, hares and pikas) Scandentia (treeshrews) Dermoptera (colugos) Primates (lorises, lemurs, tarsiers, monkeys, apes (including humans) and relatives)

[Portal](https://en.wikipedia.org/wiki/Wikipedia:Contents/Portals):
- [Mammals](https://en.wikipedia.org/wiki/Portal:Mammals)

Taxon identifiers Xenarthra Wikidata: Q173612 Wikispecies: Xenarthra ADW: Xenarthra EoL: 1308046 GBIF: 10998477 iNaturalist: 848322 ITIS: 552289 NCBI: 9348 Paleobiology Database: 97907 Paleobiology Database: 43524

Authority control databases National United States France BnF data Czech Republic Israel Other Yale LUX

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Adapted from the Wikipedia article [Xenarthra](https://en.wikipedia.org/wiki/Xenarthra) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Xenarthra?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.