Fossil findings solve riddles about "primeval armadillos"

Complete skeletons of the aetosaur typothorax found for the first time

Typothorax © Matt Celeskey
Read out

They resembled armored giant armadillos, but much more was not known by the more than 200 million years ago. Now scientists in New Mexico have discovered for the first time two almost complete skeletons of the Aetosaurus Typothorax and thus gained completely new insights into the world of these primeval reptiles. Thus, these turned out, among other things, as the authors of world-known, but not yet assigned footprints.

The reptiles from the group of the Aetosaurs were the dominant large herbivores in the Late Triassic, the era 230 to 200 million years ago, when the first dinosaurs were just beginning to develop. Similar to oversized armadillos, the aetosaurs were protected by a shell of overlapping bone plates, and some species also carried massive horns and bony tips on the neck armor to protect them from predators. Fragments of this characteristic armor have been found, inter alia, in Germany, the USA or Scotland. Complete fossils have been an absolute rarity. There was not a single complete skeleton of the type Typothorax. The knowledge of these animals is correspondingly incomplete.

New finds refute old ideas

Now scientists in the "Badlands" of New Mexico have for the first time discovered two well-preserved and almost complete specimens of Typothorax and prepared and analyzed them over many years of work. For the first time, they give a deeper insight into the anatomy and way of life of the hitherto mysterious animals that disappeared from Earth during the mass extinction at the end of the Triassic.

"We now know that some pre-existing ideas about these animals were wrong, " explains Andy Heckert, a professor of geology at Appalachian State University. "For the first time we get a realistic estimate of the size of these animals, with only 2.5 meters in length and about 100 kilograms in weight, they are nowhere near as much as we thought. We also know now that some of the bony tips that we assumed dragging along the edges of the armor actually only surrounded the cloaca. "

"Combination of armadillo and crocodile"

The new findings show that the body of Typothorax was not only back-mounted but fully armored, even the legs and feet were covered with tiny bony scales. The front legs seem to be similar to the today's crocodiles to attach laterally to the body, the hind legs, however, were significantly longer and upright. "A very interesting feature is that the front half of the skeleton is so petite that we would probably have assigned it to a cub if it had not been connected to the rest, " said Heckert. display

The paliontologist describes the first impression as the "one animal, which was assembled by a committee of a crocodile and a scavenger." From the short, thick hoses, kurzschn uzigen The skulls and small, leafy teeth of the aetosaurs tell the paleontologists that the animals may feed on succulent roots, which they can choose from Dig in the ground.

Researchers in the Discovery of Typothorax Skeletons New Mexico Museum of Natural History and Science

World-wide traces turn out to be Aetosaurus impressions

Also new insights into the movement of the animals were the Pal ontologen from the fossils. Because usually only feet are rarely completely preserved, so that a comparison with conserved Fu spuren is rarely possible. But the exceptionally well-preserved footage of the skeletons now discovered revealed something of a surprise: the footprints previously known as Brachychirotherium, of which various forms have been discovered around the world, are almost extant sure of an aetosaur. "Brachychirotherium traces show an almost perfect correspondence with the bones in the aetosaur, " explains Spencer Lucas, curator at the New Mexico Museum of Natural History. The results of the new fossil evaluations have now been published in the journal Journal of Vertebrate Paleontology .

(Society of Vertebrate Paleontology, 02.06.2010 - NPO)