A new study has found that extinct glyptodonts were indeed ancient armadillos that evolved into a size of a small car.
Thinking that extinct glyptodonts are related to armadillos is not a surprising observation. After all, both species share the same body shapes, bony skin and armored shell. However, experts could not grant a sure spot for the glyptodonts in the family tree.
Now, a group of international researchers were able to discover that glyptodonts were really armadillos, with giant armadillo (Priodontes maximus) and pink fairy armadillo (Chlamyphorus truncatus) as their closest relatives.
In the past, nobody knew how to classify glyptodonts. Experts could not seem to decide which group of mammals the species represent. While some said it belongs to the armadillo group, others thought that the species were distant members of Xenarthra, which includes anteaters, tree sloths and also, the mammals currently responsible for increased leprosy cases, armadillos.
Charles Darwin was able to obtain partial samples of glyptodonts during the 19th century, yet there has been no clear answer.
So to be able to end the identity crisis once and for all, scientists studied fossils of ancient glyptodonts.
Digging Through The DNA
To ensure that their study is comprehensive enough, the researchers included genomic proof from the species using DNA methods. Scientists from different parts of the world contributed a wide range of samples for the study.
Fossil genomic specimens are often poorly preserved. True enough, despite the several specimens nominated, only a fragment of the upper part of the shell was deemed suitable for the study.
The fossil was from an unidentified species of Doedicurus, which is a large glyptodont that walked planet Earth some 10,000 years ago.
The team arranged the complete genomic material of the species and compared it to that of modern Xenarthrans.
Truth About Glyptodonts
The findings of the study showed that glyptodonts not only originated from giant armadillo (Priodontes maximus) but also from the modern armadillo called pichiciego (Chlamyphorus truncatus) or pink fairy armadillo.
In contrast to previous speculations that glyptodonts were from ancient Xenarthrans, the team found that the species most likely originated from ancestors with linear connections to the modern Chlamyphorus.
"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," says co-author Frédéric Delsuc from the French National Center for Scientific Research. "Taxonomically, they should be regarded as no more than another subfamily of armadillos, which we can call Glyptodontinae."
Why The Evolution?
The reason for the evolution of the species is both an interesting and amusing concept to study. Although there has been no explanation behind it, experts have some suggestions.
Firstly, the pink fairy armadillo, which weighs about 4 ounces, may have had that small size because of its burrowing activity. Scientists say it only makes sense for such animal to have a small size to facilitate digging.
Secondly, the bigger size of glyptodonts may have something to do with protective needs against predators.
Extinction In Question
The cause of the species' disappearance remains unclear. Researchers say human intervention and climate change may play a part. Simply put, glyptodonts may have faced the same situation as the sloths, mastodons and other mammals that have gone extinct as well.
The study was published in Current Biology on Monday, Feb. 22.