Pilosa Explained

The order Pilosa is a clade of xenarthran placental mammals, native to the Americas. It includes anteaters and sloths (which include the extinct ground sloths). The name comes from the Latin word for "hairy".^[1]

Origins and taxonomy

The biogeographic origins of the Pilosa are still unclear,^[2] but they can be traced back in South America as far as the early Paleogene (about 60 million years ago, only a short time after the end of the Mesozoic Era). The presence of these animals in Central America and their former presence in North America is a result of the Great American Interchange. A number of sloths were also formerly present on the Antilles, which they reached from South America by some combination of rafting or floating with the prevailing currents.

Together with the armadillos, which are in the order Cingulata, pilosans are part of the larger superorder Xenarthra, a defining characteristic of which is the presence of xenarthrals (extra formations between lumbar vertebrae). In the past, Pilosa was regarded as a suborder of the order Xenarthra, while some more recent classifications regard Pilosa as an order within the superorder Xenarthra. Earlier still, both armadillos and pilosans were classified together with pangolins and the aardvark as the order Edentata (meaning toothless, because the members do not have front incisor teeth or molars, or have poorly developed molars). Edentata was subsequently realized to be polyphyletic; it contained unrelated families and was thus invalid.

Classification

See main article: List of pilosans.

Taxonomy

Order Pilosa

• Suborder Vermilingua Illiger 1811 em. Gray 1869 (Anteaters)
  • Family Cyclopedidae Pocock 1924 (Silky anteaters)
  • Family Myrmecophagidae Gray 1825
• Suborder Folivora Delsuc et al. 2001^[3] (Sloths)
  • Superfamily †Megalocnoidea Delsuc et al. 2019
    • Family †Megalocnidae Delsuc et al. 2019 (megalocnid ground sloths of the Caribbean)
  • Superfamily Megatherioidea Gray 1821
    • Family Bradypodidae Gray 1821 (three-toed sloths)
    • Family †Megalonychidae Gervais 1855 (megalonychid ground sloths)
    • Family †Megatheriidae Gray 1821 (megatheriid ground sloths)
    • Family †Nothrotheriidae Ameghino 1920 (nothrotheriid ground sloths)
  • Superfamily Mylodontoidea Gill 1872
    • Family Choloepodidae Pocock 1924 (two-toed sloths)
    • Family †Mylodontidae Gill 1872 (mylodontid ground sloths)
    • Family †Scelidotheriidae Ameghino 1889 (scelidotheriid ground sloths)

Phylogeny

Major families within Pilosa

Cladogram of living Pilosa^{[4] [5]}

Notes and References

1. Book: Kidd, D.A. . 1973 . Collins Latin Gem Dictionary . Collins . London . 0-00-458641-7. 248.
2. A proposed clade, Atlantogenata, would include Xenarthra and early African mammals.
3. Presslee. S.. Slater. G. J.. Pujos. F.. Forasiepi. A. M.. Fischer. R.. Molloy. K.. Mackie. M.. Olsen. J. V.. Kramarz. A.. Taglioretti. M.. Scaglia. F.. Lezcano. M.. Lanata. J. L.. Southon. J.. Feranec. R.. Bloch. J.. Hajduk. A.. Martin. F. M.. Gismondi. R. S.. Reguero. M.. de Muizon. C.. Greenwood. A.. Chait. B. T.. Penkman. K.. Kirsty Penkman . Collins. M.. MacPhee. R.D.E.. Palaeoproteomics resolves sloth relationships. Nature Ecology & Evolution. 3. 7. 1121–1130. 2019. 10.1038/s41559-019-0909-z. 31171860. 174813630.
4. Miranda . Flávia R. . Casali . Daniel M. . Perini . Fernando A. . Machado . Fabio A. . Santos . Fabrício R. . Taxonomic review of the genus Cyclopes Gray, 1821 (Xenarthra: Pilosa), with the revalidation and description of new species . Zoological Journal of the Linnean Society . 183 . 3 . 687–721 . 2018 . 10.1093/zoolinnean/zlx079 . 11336/49474 . free .
5. Gibb . Gillian C. . Condamine . Fabien L. . Kuch . Melanie . Enk . Jacob . Moraes-Barros . Nadia . Superina . Mariella . Poinar . Hendrik N. . Delsuc . Frédéric . Shotgun Mitogenomics Provides a Reference PhyloGenetic Framework and Timescale for Living Xenarthrans . Molecular Biology and Evolution . 33 . 3 . 621–42. 2015 . 10.1093/molbev/msv250. 26556496. 4760074 .