Remarkable discovery: B. canadensis osteocytes, or bone cells, remaining after demineralisation of the dinosaur bone.
Credit: Mary H. Schweitzer
Chris Organ, a co-author from Harvard University, in Boston, U.S., said that the results were supported by other research based on the physical characteristics of both fossils and living species and the DNA of modern species.
In addition to shedding new light on how dinosaurs are related to birds, the new study vindicates the team's previous work, which has been the subject of much controversy.
Better results
The results of the T. rex analysis were also published in Science, and lead to a number of other scientists criticising the results via letters in the same journal.
Matthew Collins, a biomolecular archaeologist at the University of York, in England, and one of the critics of the T. rex study, said that the original criticisms stemmed from the high likelihood of contamination with ancient samples, and the poor quality of data from a mass spectrometry analysis, a technique used for determining the chemical structures of molecules.
Collins said that the previous criticism had been taken into account with the new analysis, and there were much more solid results from the mass spectrometry part of the study.
Useful criticism
"The team clearly have collagen. Now the questions shifts to, where is the collagen from?" he said. However, as the sequences are most similar to birds, and any contamination would most likely be human, that supports the idea that they are dinosaur proteins.
The flurry of criticism has actually been helpful in helping her team improve their methodology, said Schweitzer.
"The critics have such a valuable role in keeping us looking for flaws and constantly trying to improve our approaches," she said. "As it is often said, extraordinary claims require extraordinary evidence. The claim that proteins and cells and vessels can persist over this length of time is extraordinary," she said.
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