WASHINGTON (Reuters) - Scientists searching for fossils high in the Andes mountains in Chile have unearthed the remains of a tank-like mammal related to armadillos that grazed 18 million years ago.
“It looks different than almost anything out on the landscape today. There really isn’t anything that’s comparable today in terms of its body form,” John Flynn of the American Museum of Natural History in New York, one of the scientists, said in a telephone interview.
The creature, Parapropalaehoplophorus septentrionalis, was a primitive relative of a line of heavily armored mammals that culminated in the massive, impregnable Glyptodon, a two-metric ton, 10-foot(3-meter)-long beast covered in armored plates and a spiky tail.
Glyptodon, the size of a Volkswagen Beetle, died out 10,000 years ago. Parapropalaehoplophorus had similar traits, but was much smaller, at 200 pounds (90 kg) and 2-1/2 feet.
The findings were published on Wednesday in the Journal of Vertebrate Paleontology.
The creature is a member of a family called glyptodonts that originated in South America and later entered North America after the two continents joined 3 million years ago.
The scientists discovered the remains in 2004 working at 14,000 feet in the Andes.
The conditions — thin air, scarce water and bitter cold — presented challenges to the scientists. But they were not the conditions in which Parapropalaehoplophorus lived.
The scientists think the area has been thrust upward since this mammalian mini-tank lived there 18 million years ago. It was, they think, an open savannah about 3,000 feet above sea level, dotted with trees and home to grazing mammals.
“It was probably grazing on grasses. They occupied the role that on other continents sheep might have been occupying ecologically,” Flynn said.
Remains of other animals living alongside it have been found, including a variety of extinct hoofed mammals, rodents and opossum relatives. No predators have been found nearby, but the scientists think that marsupial dog-like animals and gigantic flightless birds may have been on the prowl.
But any predator would have had a hard time making a meal of Parapropalaehoplophorus or any of the glyptodonts. They were the most heavily armored mammals ever to live on Earth — similar in their armor to the spiky, formidable dinosaur Ankylosaurus that lived 50 million years earlier.
Parapropalaehoplophorus was covered by a shell of immovable armored plates, different from the hinged rows of plates on today’s armadillos.
The scientists found remains of the shell, jaws, legs and backbone. It was one of the oldest members of the glyptodont family, and the discovery prompted the scientists to craft a new evolutionary tree for glyptodonts and their closest kin.
Editing by Maggie Fox and Sandra Maler