Ancient
armored mammal from Argentina was a huge armadillo
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[February 23, 2016]
By Will Dunham
WASHINGTON (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.
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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, sabre-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!"
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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.
(Reporting by Will Dunham; Editing by Sandra Maler)
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