Glyptodont: Bizarre giant mammal which roamed South America for millions of years 'related to present-day armadillos'

Glyptodonts were about the size and shape of a VW Beetle, often weighing more than a ton

Steve Connor
Science Editor
Monday 22 February 2016 18:36
Comments
Glyptodonts were giant extinct cousins of modern armadillos that roamed South America
Glyptodonts were giant extinct cousins of modern armadillos that roamed South America

For millions of years they roamed the open grasslands of what is now South America before they went mysteriously extinct in the last Ice Age. Now scientists have decoded the genome of a fossilised glyptodont and confirmed that this bizarre mammal was related to present-day armadillos.

Heavily armoured, glyptodonts were about the size and shape of a VW Beetle, often weighing more than a ton. They possessed a heavy club at the end of their tails which they presumably swung at any sexual rivals and potential predators who got too near.

However, unlike the segmented armour of the more placid armadillo, the glyptodont’s armoured “shell” was fused into one giant carapace. Fossilised fragments from one specimen’s armoured plate has now produced enough DNA for scientists to decode the glyptodont’s entire mitochondrial genome – the non-chromosomal DNA inherited solely down the maternal line.

An analysis of the mitochondrial DNA revealed that this unusual mammal, which existed for many millions of years before it went extinct, was closely related to modern-day armadillos, a far smaller creature with a leathery, protective coat.

“Glyptodonts should probably be considered a subfamily of gigantic armadillos. We speculate that the peculiar structure of their unarticulated carapace might have evolved as a response to the functional constraint imposed by the size increase they experienced over time,” said Frederic Delsuc of the National Centre for Scientific Research in France.

The study, published in the journal Current Biology, found that glyptodonts probably separated from the last common ancestor they shared with armadillos about 35 million years ago.

“The data sheds light on the familial relations of an enigmatic creature that has fascinated many but was always shrouded in mystery. Was the glyptodont a gigantic armadillo or weird off-shoot with a fused bony exoskeleton?“ said Hendrik Poinar, an evolutionary geneticist and director of Canada’s McMaster Ancient DNA Centre in Hamilton, Ontario.

“Ancient DNA has the potential to solve a number of questions such as phylogenetic position - or the evolutionary relationship - of extinct mammals, but it is often extremely difficult to obtain usable DNA from fossil specimens. In this particular case, we used a technical trick to fish out DNA fragments and reconstruct the mitochondrial genome,” Dr Poinar said.

Register for free to continue reading

Registration is a free and easy way to support our truly independent journalism

By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists

Please enter a valid email
Please enter a valid email
Must be at least 6 characters, include an upper and lower case character and a number
Must be at least 6 characters, include an upper and lower case character and a number
Must be at least 6 characters, include an upper and lower case character and a number
Please enter your first name
Special characters aren’t allowed
Please enter a name between 1 and 40 characters
Please enter your last name
Special characters aren’t allowed
Please enter a name between 1 and 40 characters
You must be over 18 years old to register
You must be over 18 years old to register
Opt-out-policy
You can opt-out at any time by signing in to your account to manage your preferences. Each email has a link to unsubscribe.

Already have an account? sign in

By clicking ‘Register’ you confirm that your data has been entered correctly and you have read and agree to our Terms of use, Cookie policy and Privacy notice.

This site is protected by reCAPTCHA and the Google Privacy policy and Terms of service apply.

Join our new commenting forum

Join thought-provoking conversations, follow other Independent readers and see their replies

Comments

Thank you for registering

Please refresh the page or navigate to another page on the site to be automatically logged in