If you were able to take a time machine back 12,000 years to the grasslands of South America, you likely would have observed — and been subsequently baffled by — one of Charles Darwin's enigma animals.
Called Macrauchenia patachonica, the creature appeared to be a puzzling amalgamation of different species. It had the bulky body of a camel without a hump, feet resembling those of modern rhinoceros, and an extremely long neck with a short trunk not dissimilar to that of an elephant.
A plant eater, paleontologists believe Macrauchenia (or "long-necked lama") used its trunk to reach leaves and its powerful legs to escape predators. At nearly 10 feet long and weighing more than 1,000 pounds, it would have been a strange but formidable mammal on the open plains.
Ever since Darwin discovered the first fossils of Macrauchenia in Patagonia in 1834, scientists have struggled to figure out where exactly the species belongs on the evolutionary ladder. Previous efforts involving bone morphology has led researchers in a variety of completely different directions.
In 2015, an international team of scientists discovered a method for deciphering puzzles like Macrauchenia by extracting ancient collagen from fossilized bones. The protein is not only abundant in fossilized remains, but also resilient — surviving intact up to 10 times longer than DNA.
After building a collagen family tree of possible related species, the researchers analyzed the protein from Macrauchenia and reveled in the results. What they found was that the mammal wasn't linked to elephants or manatees, as previously postulated, but instead was closely related to Perissodactyla, a group that includes horses, tapirs and rhinos.
The skull and neck vertebrae of M. patachonica on display in the American Museum of Natural History in New York City. Unlike other mammals, the openings for nostrils on its skull were located just above its eyes. (Photo: Ghedoghedo/Wikipedia)
A study published this week in the journal Nature confirmed these earlier results by using a new kind of genetic analysis to accurately decode Macrauchenia's curious lineage. A team led by Michi Hofreiter, a paleogenomics expert at the University of Potsdam, was able to extract mitochondrial DNA from a fossil found in a cave in South America. The results backed up the relation to horses and rhinos, adding that Macrauchenia split from this group 66 million years ago.
"We now have found a place in the tree of life for this group, so we can now also better explain how the peculiarities of these animals evolved," Hofreiter told CNN. "And we lost a pretty old branch on the mammalian tree of life when the last member of this group went extinct."
According to the fossil record, Macrauchenia died out in South America between 10,000 to 20,000 years ago, roughly around the same time humans began their rise on the continent.
Both the collagen and mitochondrial DNA breakthroughs are offering paleontologists unprecedented windows into the evolution of life on Earth. The researchers say they'll next use the techniques to analyze fossils from long-extinct species like ancient sloths, dwarf elephants, giant lizards, and more. The technology is so sensitive, it could unravel the lineages of extinct species not just from tens of thousands of years ago, but millions.
"Certainly 4 million years will not be a problem," collagen study collaborator Matthew Collins, a bioarchaeologist at the University of York in the U.K., told Nature. "In cold places, maybe up to 20 million years."