Xenarthra and Pholidota (Armadillos, Anteaters, Sloths and Pangolins)
Rose, K.D. and Gaudin, T.J., 2010. Xenarthra and Pholidota (armadillos, anteaters, sloths and pangolins). eLS.
The mammalian order Xenarthra includes the armadillos, sloths and anteaters, and the extinct glyptodonts; the mammalian order Pholidota comprises the pangolins or scaly anteaters. Although they were once thought to be closely related, Xenarthra is now generally considered to represent one of the four primary divisions of placental mammals, with pangolins placed in a separate division. Xenarthrans are united by a suite of unusual anatomical features, primary among them the presence of extra joints in their backbones, whereas pangolin’s most notable feature is their external covering of overlapping, horny scales. Both xenarthrans and pholidotans are typified by adaptations for digging and for feeding on ants and termites, though climbing forms are also common, and sloths and their relatives are herbivorous. Both orders are relatively small, with Xenarthra comprising 31 living species and Pholidota only 8, but Xenarthra also includes a very extensive extinct radiation of highly unusual mammals, including giant herbivorous sloths and the massively armoured, herbivorous glyptodonts. Xenarthrans are found in a variety of habitats throughout Central and South America, as well as southern North America, whereas pangolins are confined to the Old World tropics, from sub-Saharan Africa to southeast Asia, mostly in forested habitats.
Key words: Bradypus, Choloepus, ecology, biology, physiology, distribution, evolution