Editing Xenarthra (section)

==Characteristics==
Xenarthrans share several characteristics that are not present in other placental mammals, which suggest that xenarthrans descend from subterranean diggers. The name Xenarthra derives from the two [[ancient Greek]] words {{wikt-lang|grc|ξένος}} ({{grc-transl|ξένος}}), meaning "strange, unusual", and {{wikt-lang|grc|ἄρθρον}} ({{grc-transl|ἄρθρον}}), meaning "joint",<ref>{{Cite book |title=Abrégé du dictionnaire grec français |last=Bailly |first=Anatole |date=1981-01-01 |publisher=Hachette |isbn=978-2010035289 |location=Paris |oclc=461974285 }}</ref><ref>{{Cite web |url=http://www.tabularium.be/bailly/ |title=Greek-french dictionary online |last=Bailly |first=Anatole |website=www.tabularium.be |access-date=May 2, 2020 }}</ref> and refers to their vertebral joints, which have extra articulations that are unlike other mammals. The [[ischium]] of the pelvis is also fused to the [[sacrum]] of the spine.<ref name="Delsuc2001">{{Cite journal | last1 = Delsuc | first1 = Frédéric | last2 = Catzteflis | first2 = François M. | last3 = Stanhope | first3 = Michael J. | last4 = Douzery | first4 = Emmanuel J. P. | title = The evolution of armadillos, anteaters and sloths depicted by nuclear and mitochondrial phylogenies: implications for the status of the enigmatic fossil ''Eurotamandua'' | journal = Proc. R. Soc. Lond. B | date = August 2001 | volume = 268 | issue = 1476 | pages = 1605–15 | url = http://fdelsuc.perso.neuf.fr/fd_files/Delsuc-ProcRSocB01.pdf | doi = 10.1098/rspb.2001.1702 | pmc = 1088784 | pmid = 11487408 | access-date = 2013-01-04 | archive-date = 2016-03-04 | archive-url = https://web.archive.org/web/20160304042457/http://fdelsuc.perso.neuf.fr/fd_files/Delsuc-ProcRSocB01.pdf | url-status = dead }}</ref> Xenarthran limb bones are typically robust, with large processes for muscle attachment. Relative to their body size, living xenarthrans are extremely strong.<ref>{{cite book |last=Webb |first=S. David |date=2001 |editor-last=Hulbert |editor-first=Richard C. |title=The Fossil Vertebrates of Florida |publisher=University Press of Florida |pages=176 |chapter=Chapter 10: Mammalia 2: Xenarthrans |isbn=0-8130-1822-6}}</ref> 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 [[testicle]]s inside the body, which are located between the bladder and the rectum.<ref>{{cite journal |pmid=20413907 |year=2010 |last1=Kleisner |first1=K |last2=Ivell |first2=R |last3=Flegr |first3=J |title=The evolutionary history of testicular externalization and the origin of the scrotum |volume=35 |issue=1 |pages=27–37 |journal=Journal of Biosciences |doi=10.1007/s12038-010-0005-7|s2cid=11962872 }}</ref> Xenarthrans have the lowest [[Basal metabolic rate|metabolic rates]] among [[theria]]ns.<ref name="Basal Metabolic Rates in Mammals: A">{{cite journal |first1=M. A. |last1=Elgar |first2=P. H. |last2=Harvey |year=1987 |title=Basal Metabolic Rates in Mammals: Allometry, Phylogeny and Ecology |journal=Functional Ecology |volume=1 |issue=1 |pages=25–36 |jstor=2389354 |doi=10.2307/2389354|bibcode=1987FuEco...1...25E }}</ref><ref>{{cite journal |first1=Barry G. |last1=Lovegrove |year=2000 |title=The Zoogeography of Mammalian Basal Metabolic Rate |journal=The American Naturalist |volume=156 |issue=2 |pages=201–19 |doi=10.1086/303383 |pmid=10856202 |jstor=3079219|s2cid=4436119 }}</ref>

Xenarthran forms and lifestyles include:
* Armadillos: Mostly small and some larger omnivores and insectivores with flexible banded body armor
* Glyptodonts: Large herbivores with a rigid semi-spherical carapace
* Pampatheres: Large herbivores (and possibly omnivores) with banded body armor
* Anteaters: Small to large specialized feeders on social insects 
* Tree sloths: Medium-sized [[folivore]]s specialized for life hanging upside-down in trees
* Ground sloths: Medium to very large ground-living herbivores (and possibly omnivores)
* Aquatic sloths: ''[[Thalassocnus]]'', a medium-sized herbivore, is the only known aquatic sloth