That surprising fact falsifies a 13-year-old study and may help explain why dinosaurs were able to dominate the planet for 160 million years, said Holly Woodward, MSU graduate student in the Department of Earth Sciences and co-author of a paper published Aug. 3 in the journal "PLoS ONE."
"If we were trying to find evidence of dinosaurs doing something much different physiologically, we would expect it to be found in dinosaurs from an extreme environment such as the South Pole," Woodward said. "But based on bone tissues, dinosaurs living within the Antarctic Circle were physiologically similar to dinosaurs living everywhere else.
"This tells us something very interesting; that basically from the very start, early dinosaurs, or even the ancestors of dinosaurs, evolved a physiology that allowed an entire group of animals to successfully exploit a multitude of environmental conditions for millions of years," Woodward said.
Jack Horner, Woodward's adviser and Regents Professor of Paleontology/Curator of Paleontology at MSU's Museum of the Rockies, said Woodward's findings are consistent with other results from the museum's histology lab.
"I think the most important finding is that polar dinosaurs don't seem to be any different than any other dinosaurs in respect to how their bones grew," Horner said. "Dinosaurs have annual growth lines and those that don't have them are simply not yet a year old."
Woodward said she conducted her research after reading a 1998 study about polar dinosaurs. Intrigued by the study, she decided to review the findings and received a National Science Foundation grant that allowed her to travel to Australia last summer, set up a histology laboratory and analyze bones in a rare collection in Australia's Melbourne Museum.
Woodward analyzed the bone tissue of 17 dinosaurs that lived 112 to 100 million years ago during the latter part of the Early Cretaceous Period. All but one of the dinosaurs in her study were plant eaters. All lived in the Antarctic Circle in what is now known as the Australian state of Victoria.
Also participating in the study were the authors of the original study: Anusuya Chinsamy at the University of Cape Town in South Africa, Tom Rich at the Melbourne Museum and Patricia Vickers-Rich at Monash University in Australia.
The three scientists who conducted the original study welcomed her analysis and didn't mind that she falsified their hypothesis, Woodward said. She added that the new study looked at more dinosaur bones than the original study because more bones from the polar dinosaurs were available. Paleontologists have been adding to the collection over the past 25 to 30 years.
The original study looked at the bone microstructure of the polar dinosaurs and concluded that the differences they saw indicated that some dinosaurs survived harsh polar conditions by hibernating, while others evolved in a way that allowed them to be active year-round, Woodward said.
The new study showed that all but the youngest dinosaurs had "Lines of Arrested Growth" or LAGs, Woodward said. Since the hibernation hypothesis was based on the presence or absence of LAGs, the new study falsified the hypothesis.
LAGSs, in a bone cross section, look like tree rings, Woodward said. Like tree rings, they are formed when growth temporarily stops.
"Research on animals living today suggests that LAGs form annually, regardless of latitude or climate," Woodward said. "Like tree rings, LAGs can be counted to age an animal, so that the absence of these marks likely indicates a dinosaur was less than a year old. These marks have also been found in dinosaurs that lived at much lower latitudes having no need to hibernate."
The new study doesn't mean there was nothing unique about polar dinosaurs, but those qualities aren't apparent in bone tissue, Woodward said.
"It is very likely that dinosaurs living in different environments evolved specific adaptations – either physical or behavioral – to cope with environmental conditions," she said. "Analysis of bone microstructure can tell us a great deal about growth, but some things just aren't recorded in bone tissue."
Evelyn Boswell | EurekAlert!
Sea ice extent sinks to record lows at both poles
23.03.2017 | NASA/Goddard Space Flight Center
Less radiation in inner Van Allen belt than previously believed
21.03.2017 | DOE/Los Alamos National Laboratory
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
23.03.2017 | Life Sciences
23.03.2017 | Power and Electrical Engineering
23.03.2017 | Earth Sciences