New Skeletons from the Age of Dinosaurs Answer Century-Old Questions





More than 100 years ago paleontologist E. D. Cope of "Dinosaur Wars" fame found a few fragmentary bones of a reptile in the deserts of New Mexico. He named the reptile Typothorax. A century later Typothorax, which belongs to a group of reptiles called aetosaurs, remained something of a mystery, known mainly from pieces of armor, a few limb bones, and some sections of tail.

Now, thanks to two remarkably complete skeletons discovered by volunteers and described in the latest issue of the Journal of Vertebrate Paleontology, paleontologists are finally revealing what Typothorax really looked like, how large it was, how it walked, and myriad other questions. Typothorax is also one of the last large herbivores to evolve in the Late Triassic, before dinosaurs would come to dominate the planet.

Reminiscent of giant armadillos, aetosaurs were widespread during Late Triassic times (230 -- 200 million years ago). The largest species of aetosaur grew up to 5 meters long, although the two new specimens, representing a species called Typothorax coccinarum, were smaller growing up to 2.5 meters long. All were covered by a protective armor of overlapping bony plates, but some species sported massive spikes protecting the neck region -- an additional deterrent to any hungry predator. Fragments of the characteristic bony armor are well known to paleontologists, but complete specimens of any aetosaur are very rare and none were known for Typothorax prior to the discovery of these specimens. The ornamentation on the plates varies from species to species and paleontologists have long recognized them as a diverse and important group of plant eaters living alongside some of the earliest dinosaurs. However, because of the rarity of more complete material they remain something of an enigma. Now we can say a lot more about these strange creatures which Dr. Andy Heckert, the lead author of the study and a geology professor at Appalachian State University, regards as an "animal designed by a committee combining a crocodile with a cow and armadillo."


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