The headless horseman would quickly make friends with an Asian ankylosaur; where the former tends to miss its head, these dinosaurs are often found without their bodies. In fact, the lack of ankylosis bodies has upset paleontologists, who are eager to learn more about how powerful herbivores have become heavily armored, rinsed-tailed tanks.
Now, an international team of researchers has described the post-cranial remains of an ankylosaur in the Gobi Desert of Mongolia, extending paleontologists’ understanding of the diversity and evolution of this family. The team suggests that the ankylosaurs may have used digging for defensive or strategic purposes. Their research on a Cretaceous ankylosis – still associated with a particular species because ankylosaurs are described based on their skulls, and this skeleton was found without one – was published today in Scientific Reports.
These ankylosaur fossils are incorporated into a nugget-shaped piece. It died about 70 million years ago, and although it was discovered about 50 years ago, it took until 2008 for an excavation team to have enough resources and time to analyze the fossil. He was transported to a South Korean laboratory in 2012 to be prepared and returned to Mongolia four years later.
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“The skeletons of the articulated body 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 have studied lately provides valuable information about their 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 pedal phalanges. [toes] in time. ”
You may think that an ankylosaur that has a rigid body is not news. But Lee’s team found that this Mongolian dinosaur has even less flexibility than its North American ankylosis cousins, perhaps to support its longer tails or because of their molten vertebrae. The small number of fingers, their authors wrote, probably appeared as an adaptation to support their greater weight. This would also have reduced animal mobility, making Asian ankylosis more tank-like than previously thought.
Perhaps most significantly, the paleontological team claims that the ankylosaurs could have been built to dig. That skeletal rigidity would have stabilized the animal when digging with its forelimbs, they wrote, and the slight curve to the toes would have given the front legs a trowel shape. The authors do not suggest that ankylosaurs were buried animals in themselves, more so that, when faced with a ferocious theropod, they could dig trench-like depressions and spin downward, with only the bony skin exposed on the surface. Lee compares this behavior to modern horned lizards.
“We are curious if the young ankylosaurs were also able to dig,” Lee said. “Baby ankylosaurs do not have extended armor on their bodies and this must have made them vulnerable to predators. If babies could dig, then living in underground spaces seems possible, as armadillos do today ”.
This is speculative, but having a well-articulated skeleton gives future paleontologists something more to look at than a thick skull. The study’s authors found perforated holes in the skeleton, evidence of dermestid beetles, which are known for their appetite for rotting flesh. This suggests that the animal was placed around for at least a post-mortem time.
“Digging like modern elephants in terms of minerals, food or water, we could see, because this behavior was also suggested for sauropods,” said ReBecca Hunt-Foster, a paleontologist for the Utah National Dinosaur Monument, which is not affiliated. with the new paper. “Perhaps they used their excavations to dig nests. However, the behavior can be difficult to deduce only from the body’s fossils. ”
Researchers have also discovered five theropod phalanges embedded in the ankylosaur’s ribs – clearly this dinosaur had good reason to wear so much protection.