The headless rider would make quick friends with an Asian ankylosaur; where the former tends to miss the head, these dinosaurs are often found without their body. In fact, the scarcity of ankylosaur bodies has bothered paleontologists, who are eager to learn more about how strong herbivores became stick-tailed, heavily armored tanks.
Now, an international team of researchers has described the post-cranial remains of an ankylosaur from the Gobi Desert of Mongolia, broadening paleontologists ’understanding of the diversity and evolution of this family. The team suggests that ankylosaurs may have used the excavation for defensive or strategic purposes. His research on a Cretaceous ankylosaur, yet to be associated with a particular species, as ankylosaurs are described based on their skulls, and this skeleton was found without one. published today in Scientific Reports.
The fossils of this ankylosaur are embedded in a chicken mold. It died about 70 million years ago, and although it was discovered about 50 years ago, it was not until 2008 that an excavation team had enough resources and time to analyze the fossil. He was transported to a South Korean laboratory in 2012 to prepare it and returned to Mongolia four years later.
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“The articulated body skeletons of armored dinosaurs are quite rare,” Yuong-Nam Lee, a paleontologist at Seoul National University in South Korea and co-author of the paper, said in an email. “The almost complete skeleton we studied recently provides valuable information about its evolution and behavior. By comparing our specimen with other related dinosaurs, we now know that Asian armored dinosaurs developed rigid bodies and decreased the number of phalanges. of pedals [toes] through time “.
You may think that an ankylosaur with a rigid body is not news. But Lee’s team found that this Mongolian dinosaur had even less flexibility than its North American ankylosaur cousins, perhaps to support its longer tails or because of its fused vertebrae. The authors wrote that the small number of toes probably occurred as an adaptation to support their higher weight. This would also have reduced the mobility of the animals, making Asian ankylosaurs even more tank-like than previously thought.
Perhaps most significantly, the paleontological team argues that ankylosaurs may have been built to dig. That skeletal stiffness would have stabilized the animal as it dug with its forelimbs, they wrote, and the slight curve in its toes would have given its forelegs a paddle shape. The authors do not suggest that ankylosaurs were digging animals, per se, rather than that, when confronted with a ferocious theropod, they could dig trench-like depressions and sink, only with bony skin exposed to the surface. Lee compares this behavior to modern bathed lizards.
“We’re curious to see if the young ankylosaurs were also able to dig,” Lee said. “Ankylosaur babies lack extensive body armor, and this should make them vulnerable to predators. If babies could dig, it seems possible to live in underground spaces, as armadillos do today ”.
This is speculative, but having a well-articulated skeleton provides future paleontologists with something more to look at than a thick skull. The study authors found perforated holes in the skeleton, evidence of dermis beetles, known for their appetite for rotting flesh. This suggests that the animal was there for at least a post-mortem time.
“I was able to dig like current elephants in terms of minerals, food, or water, as this behavior has also been suggested for sauropods,” said ReBecca Hunt-Foster, a paleontologist at the Utah-affiliated Dinosaur National Monument. . with the new role. “It is possible that they also used the excavations to dig nests. However, the behavior can be difficult to infer from only body fossils.
The researchers also found five theropod phalanges embedded in the ankylosaur’s ribs, of course this dinosaur had good reason to carry so much protection.