Studies change conventional knowledge on dinosaurs

Dinosaur fossils were discovered almost every week in China and Mongolia in 2012, stimulating the study of dinosaurs these days. Scholars pay attention not only to the excavation of new fossils but also to the ecological restoration of dinosaurs. Trace fossils such as footprints, eggs and skin as well as advanced techniques such as computerized tomography, scanning electron microscopy and isotope analysis are used to find out what kind of food dinosaurs ate, how they mated and how they raised their young. Some of the studies have overturned the conventional knowledge about dinosaurs.

Most debatable issue is food habits of dinosaurs. No more details of Deinocheirus, a large theropod dinosaur that lived during the Cretaceous, have been found since the Poland-Mongolia joint team of fossils exploration discovered the huge front paws in 1965. Scholars only estimated that the dinosaur must have been carnivorous given that most theropod dinosaurs ate meat and it had gigantic paws. Its scientific name also means “horrible hand.”

However, such estimation was overturned when Lee Yung-nam, the head of the Geological Museum under the Korea Institute of Geoscience and Mineral Resources, discovered the rest frame of Deinocheirus in Gobi Desert of Mongolia in 2006 and 2010. Lee combined the two samples and restored the whole shape of Deinocheirus for more than 50 years. Over 100 gastroliths were also found along with the body frame, so it turned out that Deinocheirus was actually herbivorous. Gastroliths are stones generated by gastric fluid when fruits or vegetables are incepted, and this is a strong proof that the animal is herbivorous. The discovery was announced at the World Society of Vertebrate Paleontology in November 2013, drawing global attention.

Studies on the appearance of dinosaurs are also active. It has been believed that dinosaurs had green skin like today’s reptiles. However, the argument that dinosaurs also had feathers for keeping warmth, which must have been as fancy as those of birds today is gaining strength.

One of the typical examples is Anchiornis that lived in the late Jurassic period. Jakob Vinther, a professor of geology at Yale University, observed melanin pigments of feathers from the Anchiornis fossils in the Beijing Museum of Natural History through electronic microscope, and found that the feathers were black, white and red. The research team assumed that the wings and legs were covered with black and white feathers while the head was decorated with red feathers in a crown shape. The team also announced in the scientific journal Science in 2010 that the red feathers in the head were not just for keeping warmth but also for courtship display.

Im Jong-deok, a researcher of the Natural Monument Center under the National Research Institute of Cultural Heritage, said, “If dinosaurs had not gone extinct after the collision of meteorites, those with feathers who were able to keep warmth must have become dominant.” He also added that “dinosaurs with feathers are the ancestors of birds today.”

The March issue of Science Dong-A will cover studies on dinosaurs that many scientists are interested in, such as dinosaurs’ intelligence or ecological system. A talk concert with Lee Yung-nam, a renowned dinosaur scholar, will be held in the headquarters of Dong-A Science in Yongsan-gu, Seoul, on March 15