xenarthra

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Pale-throated Sloth (Bradypus tridactylus)

…a species of three-toed sloth (Bradypodidae) that occurs in the tropical forests of South America, occurring in Guyana, Suriname, French Guiana, western Venezuela, Colombia and parts of Brazil. Like other sloths B. tridactylus are solitary herbivores that spend most of their lives in trees feeding on the leaves of Cecropida, Ceiba, Elizabetha, and Hevea spp. Like other sloths pale-throated sloths are known for the mutualistic relationships they share with green algae and the commensal relationship they share with “sloth moths” which live in the sloth’s fur and lay their eggs in their dung.

Classification

Animalia-Chordata-Mammalia-Xenarthra-Pilosa-Folivora-Bradypodidae-Bradypus-B. tridactylus

Images: Fernando Flores and G.dallorto

Months ago, this concept art featuring Joey, Xefros, a deer-like lusus, and another lusus trailing behind them was released. Everyone discussed the three guys on the right, but the lusus on the right was more mysterious. I believe it is a ground sloth-inspired creature that is Xefros’s lusus.


Since it is a sloth, it might move slowly, thus making it need to ride on a faster, floating platform. The overall body, especially the arms, match the ground sloth quite well. The superorder of these mammals is Xenarthra (which also includes armadillos, modern sloths, and anteaters), appropriate for an X-themed character; alternatively, it could be for the ground sloth genus Megalonyx, and Xefros’s horns do match the ears of the beast in the concept art.

Edit: this has been unofficially confirmed. Xefros last name “Tritoh” is for “tri-toes”, that is, the three-toed sloth.

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Paramylodon - Harlan’s Ground Sloth

Mounted specimen on display at the Page Museum, Los Angeles, California, USA. 

Reconstruction by Charles Knight

When: late Pliocene to Pleistocene (~5 million to 11,000 years ago) 

Where: Central and North America

What: Paramylodon is the most common of the ground sloths found at the La Brea tar pits fossil site in southern California.  Megalonyx is found here as well, and though the two sloths resemble one another very strongly, they are on opposite sides of the family tree of sloths.  Megalonyx is very closely related to the living two-toed sloth, but Paramylodon and its kin form a group at the base of sloths with no living relatives. The last common ancestor of these sloths lived roughly 30 million years ago. A suite of detailed morphological features distinguish these two sloths, found thoughout the skeleton, but perhaps the most amazing is that Paramylodon was somewhat of an armored animal. Imbedded within its skin were many tiny dermal ossicals,  which would have served to protect it from the many predators that roamed southern California at the time.

The most complete specimens of Paramylodon come from the La Brea tar pits (which is a very redundant name as la brea means the tar, but hey!). The tar formed tens of thousands of years ago, by natural seepage of the sticky and dense material from the bedrock. The tar pits looked nothing like they do today, however. There were no large ‘lakes’ of tar then. Instead what would occur is occasionally a large seepage would collect and then be covered by leaves and dirt, hiding it from view. This would create a natural trap that would ensnare whichever animal was unfortunate enough to stumble upon it. The large expanses of tar visible today are due to the excavation of the site. The site was recognized as fossil bearing in the early 1900s, bones had been discovered on Rancho La Brea for some time previous to this, but they had not been properly identified as fossils.  The Page Museum was opened on the site in 1977 in order to provide both a place for researchers to easily access and study the specimens, and to display the wondrous finds to the people of Los Angeles. 

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I have just decided that the pink fairy armadillo is not as cute as the silky anteater. For some reason we always see pictures of the giant anteater, but they aren’t very representative of anteaters in general. Of the 4 species of anteater the giant anteater is the only species that doesn’t have a prehensile tail, and the only species that isn’t at least partially arboreal. Its also significantly less cute than its little cousin.

The pictures are from Google

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Megalonyx- Jefferson’s ground sloth 

When: Late Miocene to end Pleistocene (~10 million years to 10,000 years ago)

Where: Throughout North America 

What: Megalonyx is a giant ground sloth, that grew to roughly 8-10 feet (~2.5 to 3.0 meters) long.  They are the genus of giant ground sloth most closely related to the living two-toed sloth Choloepus. Sloths originated, and most of them diversified in South America, moving northward during the great American interchange, but Megalonyx is a major exception. Its ancestors reached North America millions of years prior to the massive migrations of other South America taxa; via island hopping. This relatively early arrival allowed it to spread throughout the northern continent. Megalonyx is the only species of sloth to have reached as far north as Alaska and the Yukon. It was common in many of the lower 48 states. Like many ground sloths, Megalonyx went extinct at the end of the last glacial period. 

A more recent historical note about Megalonyx; this genus was the first fossil from the Americas to be described, and the person who did so was none other than Thomas Jefferson. He proposed the name Megalonyx for the genus, based on first material recovered - the gigantic claws. Later this genus name was formalized and a species named in his honor:  Megalonyx jeffersoni (this species is the state fossil of West Virginia). Jefferson was very hopeful that living Megalonyx would be found in the uncharted west, he told Lewis and Clark to be sure to be on the look out for this beast and report back when it was discovered. 

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Lest you thought I only cared for sloth bathing, here is another xenarthran getting clean in an adorable fashion. Enjoy!

Cute Armadillo Taking A Bath! (by WorldBirdSanctuary)