GIANT ARMADILLO RELATIVE FOUND
12.19.07 - Leído 145 veces. Enviar esta notaJennifer Viegas
Battling thin air, water shortages and freezing cold temperatures, archaeologists recently unearthed an ancient armored relative of modern armadillos that looked like a Volkswagen Beetle and later evolved into species that were as big as the iconic car.
WASHINGTON, U.S.; December 19, 2007.- The newly found mammal, now extinct, weighed in at 200 pounds and once lumbered around northern Chile, where it was found in the Andes at one of the world’s highest elevation fossil sites.
“This new 18 million-year-old species is so fascinating because it is one of the earliest and most primitive members of its family — the armored-shelled glyptodonts — suggesting that the mid-latitude Andean regions were a center of origin of early diversification for a major group of South American mammals,” co-leader of the project, John Flynn, told Discovery News.
Flynn, dean of the Richard Gilder Graduate School and chairman & Frick curator in the Division of Paleontology at New York’s American Museum of Natural History, along with co-leader Darin Croft and colleagues, excavated the gyptodont, which they named Parapropalaehoplophorus septentrionalis.
Croft admitted, “The name of this new species is a mouthful, but it does roll off the tongue nicely!”
Unlike the accordion-resembling shells on today’s armadillos, glyptodont shells consisted of mostly immovable plates made from skin bone deposits. Each species seemed to have its own unique shell pattern. P. septentrionalis’ shell, for example, was covered with tiny circular bumps.
Glyptodonts grew larger over time, with some members of the group weighing around two tons. As an early member of this animal group, the recently found Chilean specimen was smaller.
Greg McDonald, a National Park Service paleontologist who did not work on excavation, explained to Discovery News that evolution favored large sizes for the armored mammals for two reasons. First, bigger is better when fighting off predators.
“It would’ve been hard to flip them over or to have broken into their shells,” McDonald said.
Second, a large body mass would have produced more heat under the shell, keeping the animal warmer under increasingly colder temperatures.
Flynn and Croft’s team determined that the early armadillo relative lived at about 3,000 feet above sea level in an open savannah with relatively few trees. The site, now at 14,000 feet, gradually rose to become part of the Andes mountain range.
They based that conclusion on ancient plant fossils recovered at the site, along with several hundred fossil mammal specimens representing 18 species of armadillos and glyptodonts, rodents, relatives of modern opossums and several now-extinct hoofed mammals.
A paper on the finds has been accepted for publication in the Journal of Vertebrate Paleontology.
Other researchers expressed amazement over the discovery.
Alfredo Carlini, a paleontologist at the Museo de La Plata in Argentina, said the new armored mammal “is a perfect piece in the Glyptodontoidea puzzle” that “fits perfectly” with his own theories about how this group evolved.
Tim Gaudin, U.C. Foundation Professor in the Department of Biological and Environmental Sciences at the University of Tennessee at Chattanooga, said, “It is the oldest glyptodont known from any significant skeletal remains. Other early glyptodonts are known only from scraps of skeletons-isolated bones or small pieces of the carapace.”
The glyptodonts, which Gaudin described as “the most peculiar group of mammals known to paleontologists,” disappeared when humans arrived in the New World.
“Glyptodont on the half shell likely was a popular food,” McDonald deadpanned.
(Discovery News)
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