This order, formerly Edentata, includes armadillos, anteaters and sloths. All are found exclusively in the New World, although fossils are known from the Eocene of Europe and possibly Asia. In fact, some researchers believe Xenarthrans may have been distributed worldwide in the Cretaceous but evidently became restricted to South America and remained there for most of their history, evolving into numerous groups. The former order name (meaning "lacking teeth") is a misnomer, since only the anteaters lack teeth. In fact, the giant armadillo may have as many as 100 teeth. The name Xenarthra means "strange joint", referring to the extra articulations (called xenarthrales) found between the vertebrae connections. These are insect eaters with degenerate teeth, consuming their prey whole without chewing using long mucus-covered tongues.
It is believed that the sloths, anteaters, and armadillos diverged at least 75-80 million years ago and that they are at least as distinct from one another as are carnivores, bats, and primates. Work by Sarich (1985) suggests that the Xenarthra separated from other placental mammals prior to the evolution of the latter into modern orders. Earliest species are known to exist in the Paleocene, 55 million years ago. With the opening of the Panama land bridge some 3 million years ago, certain species, including the giant sloths, glyptodonts and armadillos made their way into North America.
The Xenarthra once were far more diverse than today; there are known to be ten times as many fossil as living genera.
This order includes four families, 13 genera and 29 species (Nowak). Of the 29 species of the dasypodidae family occurring in Central and South America, only the nine-banded armadillo exists in eastern US.
No members of the Xenarthra order are found in the Appalachian region, but the nearest member is included for its interest below. Besides, it's my website, and I can include this ifin I wanna.
Dasypodidae – Armadillos
name armadillo is Spanish for “little armored one”. This family includes eight genera and twenty species,
primarily located in the tropical regions of the New World. Only the nine-banded armadillo is found in the United States.
Distribution: Not found north of
southern South Carolina.
First reported by John James Audubon and John Bachman in southern
Texas, it has been expanding its range east and northward since then. It was
first recorded in the Rio Grande Valley of southern Texas in the mid-1800’s.
In 1943, it moved east of the Mississippi River.
Although introduced to Florida in the 1920's, its "natural"
migration reached Alabama in 1952 and by this time, had populated all of
Florida. They are the subject of
biomedical and genetic research, due to the identical quadruplets and their
susceptibility to leprosy (the only mammal other than man to be susceptible).
Having degenerate teeth, this is the only North American mammal that is
"armored". While some species of armadillos can curl into an armored
ball, the nine-banded armadillo relies on running to safety. They have the
ability to swim across bodies of water doggie-style, but often will literally
walk along the bottom of the watercourse to the other side. Northern limit is
defined by cold, with numerous animals in northern extremes showing signs of
frost-bite. They are second only to opossum to number of road kills, owing
partially to their reflexive nature of jumping straight up when frightened.