Ancient armored mammal from Argentina was a huge armadillo

By Will Dunham
WASHINGTON, Feb 22 (Reuters) - DNA coaxed out of a
12,000-year-old fossil from Argentina is providing unique
insight into one of the strangest Ice Age giants: a tank-like
mammal the size of a small car with a bulbous bony shell and a
spiky, club-shaped tail.
Scientists said on Monday their genetic research confirmed
that the creature, named Doedicurus, was part of an extinct
lineage of gigantic armadillos. Doedicurus was a plant-eater
that weighed about a ton and roamed the pampas and savannas of
South America, vanishing about 10,000 years ago along with many
other large Ice Age animals.
"With a length of more than three meters (10 feet) from head
to tail, it certainly looks like a small car, like a Mini or
Fiat 500," evolutionary biologist Frederic Delsuc of France's
Université de Montpellier, one of the researchers, said.
It was a member of a group called glyptodonts that shared
the landscape with giant ground sloths, saber-toothed cats and
towering, flightless, carnivorous "terror birds." Some
glyptodonts made it as far north as southern portions of the
United States, from what is now Arizona through the Carolinas.
The researchers were able to place Doedicurus and the other
glyptodonts into the armadillo family tree after studying small
fragments of DNA extracted from bits of the creature's carapace.
They used a sophisticated technique to fish mitochondrial DNA
out from a soup of environmental contaminants that had leached
into the fossil over the eons.
They determined the glyptodont lineage originated about 35
million years ago. The oldest armadillo fossil, from Brazil, was
around 58 million years old.
Asked what someone might think upon encountering Doedicurus,
another of the researchers, evolutionary biologist Hendrik
Poinar of McMaster University in Canada said, "That's the
biggest armadillo-looking creature I've ever seen, and it has a
tail like an Ankylosaurus. Yikes!"
Doedicurus resembles the dinosaur Ankylosaurus, which also
was heavily armored and wielded a club-like tail.
The researchers said the resemblance was an example of
"convergent evolution" in which disparate organisms
independently evolve similar features to adapt to similar
environments or ecological niches.
Scientists have debated whether humans contributed to the
extinction of the glyptodonts. Poinar said he believed that
humans played a role, saying most of the large mammals of that
time were under pressure not only from climate change as Ice Age
waned but also from human hunting.
The research was published in the journal Current Biology.