xenarthran

Xenarthran Fakemon

#???, Slowth | Normal/Grass | Lazy Pokémon
#???, Therrarium | Normal/Grass | Overgrowth Pokémon

I’m slowly getting better at drawing fur!

Slowth live in the coastal jungles of eastern Taiyo, where they find a nice, cool spot in the shade and sleep for days at a time. When they wake up, they often find themselves completely covered in a thick layer of moss and algae. This doesn’t bother the Slowth, who enjoy benefits such as camouflage, and an easy (albeit slightly gross) meal.

Upon evolving into Therrarium, their bigger bodies and slower speed allows many more different species of plants to take hold in their fur. Also making their home in the fur are many species of Bug Pokémon, their presence and commitment to defending their home allowing Therrarium to use the moves Attack Order, Defend Order, and Heal Order.

(((I envy Therrarium right now. I wish I could sleep all week instead of studying for these finals…))) 

-T

Study Finds Relationship Between Glyptodonts, Modern Armadillos

New research using a novel technique to recover ancient DNA reveals that the evolutionary history of glyptodonts—huge, armored mammals that went extinct in the Americas at the end of the last ice age—is unexpectedly brief.

The work, published this week in the journal Current Biology by an international team of researchers, confirms that glyptodonts likely originated less than 35 million years ago from ancestors within lineages leading directly to one of the modern armadillo families.

Numerous species of glyptodonts lived in dense forests, open grasslands, and a variety of other ecosystems, occupying a range that stretched from what is now the southern part of the United States to the Patagonia region of South America.

“Although their disappearance has been blamed on human depredation as well as climate change, some species persisted into the early part of the modern epoch, long after the disappearance of mammoths and saber-toothed cats,“ saidRoss D.E. MacPhee, an author on the study and curator in the Museum’s Department of Mammalogy. "Like the loss of giant ground sloths, mastodons, and dozens of other remarkable mammalian species, the precise cause of the New World megafaunal extinctions remains uncertain.”

Although scientists including Charles Darwin collected partial remains of glyptodonts in the early 19th century, at first nobody knew what kind of mammal they represented. It was eventually accepted that glyptodonts must be related in some way to armadillos, the only other New World mammals to develop a protective bony shell. However, because of the many physical differences between these two groups, most paleontologists have held the view that they must have separated very early in their evolutionary history.

To try and clarify this poorly understood history, researchers Frédéric Delsuc of the French National Center for Scientific Research at the University of Montpellier and Hendrik Poinar of McMaster University worked alongside MacPhee to learn what genetic information on these ancient armored animals could reveal.

As is often the case in ancient DNA investigations, fossil genomic material is poorly preserved, and only one sample worked—a carapace fragment of an undetermined species of Doedicurus, a gigantic glyptodont that lived until about 10,000 years ago. Using a novel approach to recover genetic information from ancient specimens, the team successfully assembled the complete mitochondrial genome of Doedicurus and compared it to that of all modern xenarthrans, a group of mammals including armadillos, sloths, and anteaters.

The researchers found that instead of representing a very early, independent branch of armored xenarthrans, glyptodonts likely had a much later origin, from ancestors within lineages leading to the modern armadillo family Chlamyphoridae.

More surprising still, the study finds that the closest relatives of glyptodonts—some species of which may have weighed 2 tons or more—include not only the giant armadillo (Priodontes maximus), which can weigh up to 25 pounds, but also the 4-ounce pink fairy armadillo, or pichiciego (Chlamyphorus truncatus).

“Contrary to what is generally assumed about the distinctiveness of glyptodonts, our analyses indicate that they originated only some 35 million years ago, well within the armadillo radiation,” Delsuc said. “Taxonomically, they should be regarded as no more than another subfamily of armadillos, which we can call Glyptodontinae.”

This post was originally published on the Museum blog. 

This Fossil Friday is all in the family…the armadillo family, that is! 

This is Panochthus frenzelianus, a giant glyptodont that lived in South America, just before the extinction of the glyptodonts, at the end of the last ice age, about 30,000 years ago. Some glyptodonts grew to be over 10 feet long and may have weighed as much as a ton, including the shell. 

Although scientists including Charles Darwin collected partial remains of glyptodonts in the early 19th century, at first nobody knew what kind of mammal they represented. It was eventually accepted that glyptodonts must be related in some way to armadillos, the only other New World mammals to develop a protective bony shell. However, because of the many physical differences between these two groups, most paleontologists have held the view that they must have separated very early in their evolutionary history.

Just this week, new research by an international team of researchers, including Ross MacPhee from AMNH, that used a novel technique to recover ancient DNA revealed that instead of representing a very early, independent branch of armored xenarthrans, glyptodonts likely had a much later origin, from ancestors within lineages leading to the modern armadillo family Chlamyphoridae.

“Contrary to what is generally assumed about the distinctiveness of glyptodonts, our analyses indicate that they originated only some 35 million years ago, well within the armadillo radiation,” said researcher Frédéric Delsuc of the French National Center for Scientific Research. “Taxonomically, they should be regarded as no more than another subfamily of armadillos, which we can call Glyptodontinae.”

Learn more about this new research

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Doedicurus 

Skeleton on display at the Museo Histórico Nacional in Buenos Aires, Argentina. 

When: Pleistocene (2 million to 11,000 years ago)

Where: South America

What: Doedicurus is a glyptodont. The Glyptodontidae were a subclade of armadillos that ranged throughout South America (and North after the land bridge reappeared). Doedicurus was one of the largest glyptodons, coming in at about 12 feet (~3.6 meters) long. Its shell was gigantic, a grown person can crawl inside one of these structures, and there has been some theories that ancient peoples could have used these shells for shelter.  The shell of Doedicurus, like all glyptodonts, was different from that of the living armadillos. The carapaces were thicker and in one solid piece, unlike the several segments present in armadillos that allow them to curl into a ball. Doedicurus had a highly domed shell, that connected to its pelvis posteriorly, but was separated from its shoulder girdle. It has been speculated that glyptodons with this type of shell stored fat in this space above the shoulders, such as a modern camel stores fat in its hump. Doedicurus also had an armored skull cap, which you can see in the fossil image but sadly has been omitted from the reconstruction. 

One of the most distinctive features of Doedicurus is its spiked tail club. In most of these entries when I present something cool that you can imagine being used in intraspecific competition I have to say ‘but it was just for display or protection’. NOT THIS TIME. There is a great amount of evidence for the hypothesis that these spiked tail clubs were used in battles between males. Not all specimens of Doedicurus have a well developed pedestal for the spikes, leading researchers to conclude this was only present in males. It is very unlikely this would have been anymore of a deterrent for predators than the large shell in the first place, and just as unlikely that Doedicurus would have been agile enough to defend itself from a swift carnivorous attacker with this club. Most compelling of all, several Doedicurus specimens have been found with healed wounds in their carapaces that match the predicted impact from a rival’s tail club. 

Doedicurus, like all of the remaining glyptodonts, went extinct about 11-10,000 years ago, at the end of the last major glaciation. 

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Bath time for baby sloths

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Peltephilus - The Horned Armadillo 

Skull located in the Museo Histórico Nacional, Buenos Aires, Argentina. 

When:Oligocene to Miocene (~29 to 15 million years ago)

Where: South America    

What: Peltephilus is a primitive armadillo. This is the only known armadillo with horns, and one of only two known horned fossorial (digging) mammals. The other is Ceratogaulus, a gopher that lived somewhat contemporaneously in North America. Like Ceratogaulus, the horns of Peltephilus were for defensive purposes, and were not useful in either digging or for battles between individuals. Peltephilus was once proposed to have been a fast running meat eating armadillo, but more recent and in-depth studies have countered these claims and instead demonstrated that this 3 feet (~1 meter) long armadillo was indeed a digging herbivore like most known armadillos.

Peltephilus is the basal most armadillo known. One of its most obvious primitive features is that it has a full compliment of teeth in the front of its mouth that contact one another. All other armadillos have reduced anterior dentition and thus ‘spouts’ at the front of the mouths. These front teeth were the source for the early ideas of carnivory in this species. Even though Peltephilus was primitive in this, and other cranial and skeletal features, it is still highly derived and, well, already armadillo like in many other aspects, most notably its well developed carapace.