Check out the armor on this Fossil Friday! 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. Their teeth were small and shaped like columns, with flat surfaces for grinding up plants. 

The head of most glyptodonts was armored, and could also be retracted into the shell opening; the feet and tail were protected by armor as well. These shields deterred all but the most powerful carnivores from attacking this animal fortress. 

Both armadillos and glyptodonts have a completely bony shell covering their bodies. The shells are constructed differently, however. While an armadillo is covered by parallel rows of bony bands, enabling the animal to roll up into a ball when threatened, a glyptodont’s shell was composed of thick bony rosettes fused solidly together, which meant that glyptodont’s could not roll into a ball. 

Find this fossil in the Museum’s Hall of Primitive Mammals

Venezuelan paleontologist Ascanio Rincon shows the skull of a glyptodont found in Venezuela, in Caracas on August, 30, 2013.

Under the Venezuelan rich soil lies more than oil: paleontologists have found traces of an armadillo the size of a Volkswagen, a crocodile bigger than a bus, a mastodon of six tonnes and a saber-toothed tiger. Now, they walk after the human fossil. (AFP Photo/Juan Barreto)

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. 


Animals known to live in aardvark burrows.

The aardvark (Orycteropus afer) is the largest burrowing mammal.* Its burrows provide a home for all sorts of creatures – the porcupine, South African shelduck and anteater chat will live with aardvarks as lodgers; warthogs, hyenas and wild dogs occupy abandoned burrows.

Here’s some pictures of wild dogs digging into an aardvark burrow to get a warthog. Don’t say I don’t give you nice things.

Alright then so let’s get into the juicy Pleistocene meat of the matter. It’s well documented that ground sloths lived in burrows, and ground sloths were significantly larger than aardvarks.

Ground sloth burrows! Top photo by Givago Capistrano. Bottom photo from here.

Ground sloth burrows are huge, and if aardvarks can unwittingly provide homes for so many animals (apparently Reay H. N. Smithers recorded seventeen mammal species in aardvark burrows**) imagine the kind of crazy things you’d get living in a ground sloth burrow back in the day.

They’ve already found glyptodont and remains in ground sloth burrows (paper available as a .pdf) – so many that at first palaeontologists wondered if the burrows were made by glyptodonts. But apparently glyptodonts had terrible anatomy and couldn’t dig very well. Que sera sera. Fortunately, there were bigger xenarthrans around to provide them with a home.

What if glyptodonts and megatheres didn’t just hang out in museum exhibits, but were besties in the Pleistocene, too? (Photo from here.)

*Okay, so larger animals do dig holes – polar bears construct burrows to hibernate in – but aardvarks are certainly the largest burrowing mammal that live in burrows year round. The Guinness Book of World Records lists the wombat as the largest burrowing mammal but that’s bullshit because aardvarks are like a metre longer and twice as heavy as wombats. Take that, Australia.

**This was in Mammals of Botswana (1971) which I haven’t actually read. But I ain’t gonna waste a sweet statistic like that.

Happy National Fossil Day!!! Here in the photo archives one of our favorite fossils is the Glyptodont because he gets to walk around with his own portable dark room.

What’s your favorite fossil?

© The Field Museum, GEO79991.

Glyptodont skeleton. Glyptodont were  large, armored mammal of the family Glyptodontidae, a relative of armadillos that lived during the Pleistocene epoch.

8x10 negative



Glyptodonts and Armadillos in AMNH.
The giant one is a Panochthus, a badly photographed skull of Glyptotherium (in second image), the small Propalaehoplophorus and a modern armadillo, the six-banded armadillo (Euphractus sexcinctus).

Gliptodontes y Armadillos en el AMNH.
El gigante es un Panochthus, luego esta un cráneo mal fotografiado de Glyptotherium (en la segunda imagen), el pequeño Propalaehoplophorus y un armadillo moderno, el tatú peludo (Euphractus sexcinctus).

just2spoopy replied to your post: “oh muh gawrsh hi new followers hi how are you whats yr favorite…”:

hiii! I have a lot of fave dinosaurs, but I think my current #1 is the ankylosaurus, because it has an awesome knobby tail and a pangolin-like/turtle-y shell! :D

oh gosh, if you like those, then you would probably dig their miocene mammalian counterparts if you havent heard of em already


a glyptodont