What do Xenarthra have in common?

The Xenarthra bear several unique anatomic traits such as additional (xenarthrous) joints of lumbar vertebrae; fusion of the ischium to the anterior caudal vertebrae; a secondary scapular spine; extensive retia mirabile in the limbs; paired postrenal venae cavae; and ossified sternal ribs.

Is Xenarthra extinct?

Extinct xenarthrans include the glyptodonts, pampatheres and ground sloths. Xenarthrans originated in South America during the Paleocene about 59 million years ago. They evolved and diversified extensively in South America during the continent’s long period of isolation in the early to mid Cenozoic Era.

Are armadillos and sloths related?

Armadillos are only closely related to other xenarthrans — South American anteaters and sloths. This group is unique to North and South America, and is not closely related to any other group of mammals. The mammal that is most often confused with an armadillo is the pangolin (Order Pholidota).

Is an aardvark a Xenarthra?

Armadillos and sloths and anteaters and pangolins and even aardvarks used to be in the same order—not called Xenarthra, but Edentata, a term attributed to Félix Vicq d’Azyr and Georges Cuvier, both leading French biologists in the late eighteenth century. …

How many families are in Xenarthra?

Three families exist today, encompassing five genera and nine species. Six families, primarily ground sloths, are extinct.

Are sloths and anteaters related?

Sloths are xenarthrans – their closest relatives include anteaters and armadillos. And, among other things, large, curved claws and powerful forelimbs for digging are common xenarthran traits. The ancestors of modern sloths probably went through a similar stage.

Why are sloths not primates?

So, are sloths marsupials or primates? Sloths are mammals, but they aren’t primates or marsupials – though the groups do share some similarities. Koalas, for example, are marsupials that live in trees, eat leaves and have slow metabolisms. But sloths and koalas developed these traits independently of each other.

What is the evolutionary history of a sloth?

Research suggests that they evolved from different families of extinct animals, meaning they evolved through convergent evolution. However, both of these sloths are similar in the cultivation of algae in their fur to promote digestion. The moths that live in their fur are also essential in the growth of algae.

How many species of Xenarthra are there?

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

What is the origin of the superorder Xenarthra?

Xenarthra. The superorder Xenarthra is a group of placental mammals, extant today only in the Americas and represented by anteaters, tree sloths, and armadillos. The origins of the order can be traced as far back as the Paleocene, as early as 59 million years ago in South America. Xenarthrans developed and diversified extensively in South…

What characteristics do Xenarthrans share that are unique to them?

Xenarthrans share several characteristics not present in other placental mammals. The name Xenarthra, which means “strange joints”, was chosen because their vertebral joints have extra articulations unlike other mammals. This trait is referred to as “xenarthry”. Also, unlike other mammals, the ischium and sacrum are fused.

Is Xenarthra a sister clade to Euarchontoglires?

A comprehensive phylogeny by Goloboff et al. includes xenarthrans as a sister clade of Euarchontoglires within Boreoeutheria ( Laurasiatheria + Euarchontoglires ).