The order Pilosa is a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English ter ...

xenarthran Xenarthra (; from Ancient Greek ξένος, xénos, "foreign, alien" + ἄρθρον, árthron, "joint") is a major clade of placental mammals native to the Americas. There are 31 living species: the anteaters, tree sloths, and armadillos. Exti ...

placental Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguishe ...

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...

s, native to the Americas. It includes the

anteater Anteater is a common name for the four extant mammal species of the suborder Vermilingua (meaning "worm tongue") commonly known for eating ants and termites. The individual species have other names in English and other languages. Together wit ...

s and

sloth Sloths are a group of Neotropical xenarthran mammals constituting the suborder Folivora, including the extant arboreal tree sloths and extinct terrestrial ground sloths. Noted for their slowness of movement, tree sloths spend most of their l ...

s (which includes the extinct

ground sloth Ground sloths are a diverse group of extinct sloths in the mammalian superorder Xenarthra. The term is used to refer to all extinct sloths because of the large size of the earliest forms discovered, compared to existing tree sloths. The Caribb ...

s). The name comes from the

Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...

word for "hairy".

Origins and taxonomy

The biogeographic origins of the Pilosa are still unclear, but they can be traced back in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou ...

as far as the early

Paleogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya) to the beginning o ...

(about 60 million years ago, only a short time after the end of the

Mesozoic Era The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...

). The presence of these animals in

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

and their former presence in

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

is a result of the

Great American Interchange The Great American Biotic Interchange (commonly abbreviated as GABI), also known as the Great American Interchange and the Great American Faunal Interchange, was an important late Cenozoic paleozoogeographic biotic interchange event in which lan ...

. A number of sloths were also formerly present on the

Antilles The Antilles (; gcf, label=Antillean Creole, Antiy; es, Antillas; french: Antilles; nl, Antillen; ht, Antiy; pap, Antias; Jamaican Patois: ''Antiliiz'') is an archipelago bordered by the Caribbean Sea to the south and west, the Gulf of Mex ...

, which they reached from South America by some combination of rafting or floating with the prevailing currents. Together with the

armadillo Armadillos (meaning "little armored ones" in Spanish) are New World placental mammals in the order Cingulata. The Chlamyphoridae and Dasypodidae are the only surviving families in the order, which is part of the superorder Xenarthra, alo ...

s, which are in the order Cingulata, pilosans are part of the larger superorder

Xenarthra Xenarthra (; from Ancient Greek ξένος, xénos, "foreign, alien" + ἄρθρον, árthron, "joint") is a major clade of placental mammals native to the Americas. There are 31 living species: the anteaters, tree sloths, and armadillos. ...

, 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

pangolin Pangolins, sometimes known as scaly anteaters, are mammals of the order Pholidota (, from Ancient Greek ϕολιδωτός – "clad in scales"). The one extant family, the Manidae, has three genera: '' Manis'', ''Phataginus'', and '' Smuts ...

s and the

aardvark The aardvark ( ; ''Orycteropus afer'') is a medium-sized, burrowing, nocturnal mammal native to Africa. It is the only living species of the order Tubulidentata, although other prehistoric species and genera of Tubulidentata are known. Unlik ...

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 A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

; it contained unrelated families and was thus invalid.

Classification

Taxonomy

Order Pilosa * Suborder Vermilingua Illiger 1811 em. Gray 1869 (

Anteater Anteater is a common name for the four extant mammal species of the suborder Vermilingua (meaning "worm tongue") commonly known for eating ants and termites. The individual species have other names in English and other languages. Together wit ...

s) ** Family Cyclopedidae Pocock 1924 (

Silky anteater The silky anteater, also known as the pygmy anteater, has traditionally been considered a single species of anteater, ''Cyclopes didactylus'', in the genus ''Cyclopes'', the only living genus in the family Cyclopedidae. Found in southern Mexico ...

s) ** Family

Myrmecophagidae The Myrmecophagidae are a family of anteaters, the name being derived from the Ancient Greek words for 'ant' and 'eat' (''myrmeco-'' and '). Two genera and three species are in the family, consisting of the giant anteater, and the tamanduas. T ...

Gray 1825 * Suborder Folivora Delsuc et al. 2001 (Sloths) ** Superfamily

† A dagger, obelisk, or obelus is a typographical mark that usually indicates a footnote if an asterisk has already been used. The symbol is also used to indicate death (of people) or extinction (of species). It is one of the modern descendan ...

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 Nothrotheriidae is a family of extinct ground sloths that lived from approximately 17.5 mya—10,000 years ago, existing for approximately . Previously placed within the tribe Nothrotheriini or subfamily Nothrotheriinae within Megatheriidae, th ...

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

References

* * {{Taxonbar, from=Q143441 Mammal orders Taxa named by William Henry Flower Extant Thanetian first appearances