Editing Xenarthra (section)

=== Dentition ===
The teeth of xenarthrans differ from all other mammals. The dentition of most species is either significantly reduced and highly modified, or absent.<ref>{{Cite journal|last=Vizcaíno|first=Sergio F.|date=2009|title=The teeth of the "toothless": novelties and key innovations in the evolution of xenarthrans (Mammalia, Xenarthra)|journal=Paleobiology|volume=35|issue=3|pages=343–366|doi=10.1666/0094-8373-35.3.343|bibcode=2009Pbio...35..343V |s2cid=86798959|issn=0094-8373}}</ref> With the single exception of ''Dasypus'' armadillos and their ancestral genus ''Propraopus'', xenarthrans do not have a [[Baby teeth|milk dentition]]. They have a single set of teeth through their lives; these teeth have no functional [[Tooth enamel|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]] to chew plants, but since they lacked enamel, patterns of harder and softer [[dentin]]e 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.<ref name=":1">{{Cite book|last=Farina|first=Richard A |author2=Sergio F. Vizcaino |author3=Gerry de Iuliis|title=Megafauna; Giant Beasts of Pleistocene South America|publisher=Indiana University Press|year=2013|isbn=9780253002303|location=Bloomington}}</ref> Currently, no living or extinct xenarthrans have been found to have the standard mammalian [[dental formula]] or crown morphology derived from the ancient [[Tribosphenic molar|tribosphenic]] pattern.<ref>{{Cite journal|last1=Gaudin|first1=Timothy J.|last2=Croft|first2=Darin A.|date=2015-06-24|title=Paleogene Xenarthra and the evolution of South American mammals|journal=Journal of Mammalogy|volume=96|issue=4|pages=622–634|doi=10.1093/jmammal/gyv073|issn=0022-2372|doi-access=free}}</ref>