The research team consists of Dr. Wang Chun-Chieh and Mr. Chiang Cheng-Cheng from the National Synchrotron Radiation Research Center (NSRRC), Dr. Li Zhiheng and academician Dr. Zhou Zhonghe from the Institute of Vertebrate Paleontology and Paleoanthropology, Prof. Huang E-Wen from the Department of Materials Science and Engineering, NCTU, and Mr. Hsiao Kiko from Mr. Fossil, spent 3 years on the research and analysis of the tooth evolution from Theropoda, a dinosaur clade that is most related to ancient birds, to ancient birds, using synchrotron Transmission X-Ray Microscopy (TXM). It is the first time in history that the research team discovered the Porous Mantle Dentin of ancient birds has deteriorated and disappeared, which confirmed that the transformation of feeding habits of birds fortunately helped them to escape from a mass extinction event. The research result was published in the international journal BMC Evolutionary Biology on April 21st.
Cretaceous–Paleogene Extinction Event
How did birds, descendants of dinosaurs, escape from the mass extinction before 65 Mya, has always puzzled scientists. When meteorites struck the earth, the already frequent volcanic eruptions led to a significant amount of dust entering the atmospheric layer, which blocked the sun and hindered photosynthesis for plants, thus induced further severe impact to the global ecosystem. When plants no longer received energy from the sun, herbivores began dying due to no food sources, which eventually led to the successive extinction of carnivores. This series of food chain collapses resulted in the extinction of 75% of organisms on earth, for which the spotlight lies on the mass extinction of non-avian dinosaurs (Birds is the only survived dinosaur lineage).
Read more on the NSRRC website
Image: Fossil specimens of Sapeornis of Avialae and Microraptor of Theropoda during early Cretaceous.