March 31, 2010

Fossil of Agile ‘Roadrunner’ Dinosaur Uncovered

The fossils of a dinosaur, believed to be one of the smallest and most agile of its kind, have been discovered in China, according to findings recently published in the scientific journal Zootaxa.

Xixianykus zhangi, a theropod nicknamed the "roadrunner" because of its speed and perceived ability to evade predators, was discovered by an international team of scientists in Henan Province, China. The dinosaur is approximately 1.5 feet long, and likely used large claws to dig for termites and ants.

Dr. Corwin Sullivan, a paleontologist from the Chinese Academy of Sciences in Beijing and one of the study's authors, noted that the "proportions of Xixianykus are among the most extreme ever recorded for a theropod dinosaur" in an interview with Matt Walker of BBC Earth News.

This is the first theropod of its type to be discovered in China. The incomplete skeleton found by the research team included seven vertebrae, the synsacrum, some ribs, portions of the pelvic girdle and most of the right hindlimb.

From the fossils recovered, it shows that the dinosaur's skeleton would have helped keep the creature stable and conserve energy in its movements. Much like many modern-day running animals, the femur of the Xixianykus zhangi is extremely short compared to its lower leg and foot, Sullivan noted.

"This doesn't provide a basis for estimating its top speed, but it does show that Xixianykus was a highly efficient runner," he told Walker on Tuesday.

"Some modern termite-eating species travel long distances between colonies of their prey, so as an efficient runner Xixianykus would have been able to follow this pattern," added co-author Dr. David Hone, also of the Chinese Academy of Sciences.

"Any small dinosaurs would be vulnerable to predators too and the ability to make a speedy exit if danger threatened would be valuable to an animal like this."


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