Extinct Glyptodonts were Massive Armadillos, Ancient DNA Reveals
The mysterious, armored and extinct glyptodonts were actually giant armadillos. Scientists have conducted a new genetics study that reveals that glyptodonts likely originated less than 35 million years ago from ancestors within lineages leading directly to one of the modern armadillo families.
Although scientists collected partial remains of glyptodonts in the early 19th century, no one really knew what to make of the massive mammals the remains represented. At the time, it was accepted that glyptodonts must be related to armadillos in some way. However, because of the many physical differences between the two groups, most paleontologists have held the view that they must have separated very early in their evolutionary history.
In this latest study, the researchers decided to take a closer look at glyptodont's relationships to armadillos. The scientists included genomic evidence from extinct species using "ancient" DNA techniques. In the end, the researchers were able to assemble the complete mitochondrial genome of the species and compared it to modern xenathrans, which is the group to which armadillos belong.
"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 Frederic Delsuc, one of the researchers, in a news release. "Taxonomically, they should be regarded as no more than another subfamily of armadillos, which we can call Glyptodontinae."
The findings reveal that this supersized species is more closely related to the armadillo than anyone expected.
"Despite their ungainly appearance, different species of glyptodonts occupied habitats as distinct as open grassland and dense woodland, all the way from Patagonia to the southern parts of the continental United States," said Ross MacPhee, one of the researchers. "Although their disappearance has been blamed on human depredation as well as climate change, some species persisted into the early part of the modern or Holocene epoch, long after the disappearance of mammoths and saber-toothed cats. 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."
The findings are published in the journal Current Biology.
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