Pilosa
Encyclopedia
The order Pilosa is a group of placental mammal
s, extant today only in the Americas. It includes the anteater
s and sloth
s, including the recently extinct ground sloth
s.
The biogeographic origins
of the Pilosa is still unclear but they can be traced back in South America
as far as the early Tertiary
(about 60 million years ago, or only a short time after the end of the dinosaur era
). The presence of these animals in Central America
is explained by the Great American Interchange
.
Together with the armadillo
s, Pilosa is part of the larger group Xenarthra
. In the past Pilosa was regarded as a suborder of the order Xenarthra, while some more recent classifications regard Pilosa as an order within a superorder Xenarthra. Earlier still, both armadillos and Pilosans were classified together with pangolin
s 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). It was subsequently realized that Edentata was polyphyletic—that it contained unrelated families and was thus invalid.
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s, extant today only in the Americas. It includes the anteater
Anteater
Anteaters, also known as antbear, are the four mammal species of the suborder Vermilingua commonly known for eating ants and termites. Together with the sloths, they compose the order Pilosa...
s and sloth
Sloth
Sloths are the six species of medium-sized mammals belonging to the families Megalonychidae and Bradypodidae , part of the order Pilosa and therefore related to armadillos and anteaters, which sport a similar set of specialized claws.They are arboreal residents of the jungles of Central and South...
s, including the recently extinct ground sloth
Ground sloth
Ground sloths are a diverse group of extinct sloths, in the mammalian superorder Xenarthra. Their most recent survivors lived in the Antilles, where it has been proposed they may have survived until 1550 CE; however, the youngest AMS radiocarbon date reported is 4190 BP, calibrated to c. 4700 BP...
s.
The biogeographic origins
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...
of the Pilosa is still unclear but they can be traced back in South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
as far as the early Tertiary
Tertiary
The Tertiary is a deprecated term for a geologic period 65 million to 2.6 million years ago. The Tertiary covered the time span between the superseded Secondary period and the Quaternary...
(about 60 million years ago, or only a short time after the end of the dinosaur era
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
). The presence of these animals in Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
is explained by the Great American Interchange
Great American Interchange
The Great American Interchange was an important paleozoogeographic event in which land and freshwater fauna migrated from North America via Central America to South America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor and bridged the formerly separated continents...
.
Together with the armadillo
Armadillo
Armadillos are New World placental mammals, known for having a leathery armor shell. Dasypodidae is the only surviving family in the order Cingulata, part of the superorder Xenarthra along with the anteaters and sloths. The word armadillo is Spanish for "little armored one"...
s, Pilosa is part of the larger group Xenarthra
Xenarthra
The superorder Xenarthra is a group of placental mammals , existent today only in the Americas and represented by anteaters, tree sloths, and armadillos. The origins of the order can be traced back as far as the Paleogene in South America...
. In the past Pilosa was regarded as a suborder of the order Xenarthra, while some more recent classifications regard Pilosa as an order within a superorder Xenarthra. Earlier still, both armadillos and Pilosans were classified together with pangolin
Pangolin
A pangolin , also scaly anteater or Trenggiling, is a mammal of the order Pholidota. There is only one extant family and one genus of pangolins, comprising eight species. There are also a number of extinct taxa. Pangolins have large keratin scales covering their skin and are the only mammals with...
s and the Aardvark
Aardvark
The aardvark is a medium-sized, burrowing, nocturnal mammal native to Africa...
as the order Edentata (meaning toothless, because the members do not have front incisor teeth or molars, or have poorly-developed molars). It was subsequently realized that Edentata was polyphyletic—that it contained unrelated families and was thus invalid.
Classification
Order Pilosa- Suborder Vermilingua
- Family CyclopedidaeCyclopedidaeCyclopedidae is a family of anteaters that includes the silky anteater and its extinct relatives....
- Silky AnteaterSilky AnteaterThe Silky Anteater or Pygmy Anteater is a species of anteater from Central and South America, ranging from extreme southern Mexico south to Brazil Delta Amacuro Venezuela and possibly Paraguay...
, Cyclopes didactylus
- Silky Anteater
- Family MyrmecophagidaeMyrmecophagidaeMyrmecophagidae is a family of anteaters, the name being derived from the Ancient Greek words for 'ant' and 'eat' . Myrmecophagids are native to Central and South America, from southern Mexico to northern Argentina. There are 2 genera and 3 species in the family, consisting of the Giant Anteater,...
- Giant AnteaterGiant AnteaterThe Giant Anteater, Myrmecophaga tridactyla, is the largest species of anteater. It is the only species in the genus Myrmecophaga. It is found in Central and South America from Honduras to northern Argentina...
, Myrmecophaga tridactyla - Northern TamanduaNorthern TamanduaThe northern tamandua is a species of tamandua, a small anteater in the family Myrmecophagidae. They live in tropical and subtropical forests from southern Mexico, through Central America, and to the edge of the northern Andes....
, Tamandua mexicana - Southern TamanduaSouthern TamanduaThe southern tamandua, also called a collared anteater, or lesser anteater , is a species of anteater from South America. It is a solitary animal, found in many habitats from mature to highly disturbed secondary forests and arid savannas. It feeds on ants, termites and bees...
, Tamandua tetradactyla
- Giant Anteater
- Family Cyclopedidae
- Suborder Folivora
- Family Bradypodidae: three-toed sloths
- Pygmy Three-toed SlothPygmy Three-toed SlothThe Pygmy Three-toed Sloth is a three-toed sloth. It is endemic to Isla Escudo de Veraguas, an island off the coast of Panama, which separated from the mainland nearly 8900 years ago. The species is thought to have originated from isolation of individuals from the mainland population of Bradypus...
, Bradypus pygmaeus - Brown-throated Three-toed SlothBrown-throated Three-toed SlothThe brown-throated sloth is a species of three-toed sloth. It is the most common of the four species of three-toed sloth, and is found in the forests of South and Central America.-Description:...
, Bradypus variegatus - Pale-throated Three-toed SlothPale-throated Three-toed SlothThe Pale-throated sloth is a species of three-toed sloth that inhabits tropical rainforests in northern South America. It is similar in appearance to, and often confused with, the brown-throated sloth, which has a much wider distribution...
, Bradypus tridactylus - Maned Three-toed SlothManed Three-toed SlothThe maned sloth , also known as the ai , is a three-toed sloth that lives only in Brazil. It is one of only four species of three-toed sloth.-Distribution and habitat:...
, Bradypus torquatus
- Pygmy Three-toed Sloth
- Family MegalonychidaeMegalonychidaeMegalonychidae is a group of sloths including the extinct Megalonyx and the living two toed sloths. Megalonychids first appeared in the early Oligocene, about 35 million years ago, in southern Argentina , and spread as far as the Antilles by the early Miocene...
: two-toed sloths and extinct megalonychid ground sloths- Hoffman's Two-toed Sloth, Choloepus hoffmanni
- Southern Two-toed Sloth, Choloepus didactylus
- Family †MegatheriidaeMegatheriidaeMegatheriidae is a family of extinct ground sloths that lived from approximately 23 mya—11,000 years ago, existing for approximately .Megatheriids appeared later in the Oligocene, some 30 million years ago, also in South America. The group includes the heavily-built Megatherium and Eremotherium...
: megatheriid ground sloths - Family †MylodontidaeMylodontidaeMylodontidae is a family of extinct mammals within the order of Pilosa and suborder Folivora living from approximately 23 mya—11,000 years ago, existing for approximately . This family of ground sloths is related to the other families of extinct ground sloths, being the Megatheriidae, the...
: mylodontid ground sloths - Family †OrophodontidaeOrophodontidaeOrophodontidae is a family of extinct ground sloths within the order of Pilosa and suborder Folivora. The name is often disused with genus members reassigned....
: orophodontid ground sloths - Family †ScelidotheriidaeScelidotheriidaeScelidotheriidae is a family of extinct mammals within the order of Pilosa and suborder Folivora. This family of ground sloths is related to the other families of extinct ground sloths, being the Megatheriidae, the Mylodontidae, the Nothrotheriidae, and the Orophodontidae...
: scelidotheriid ground sloths
- Family Bradypodidae: three-toed sloths