The researchers also tested the bones of chickens and ostriches, both of which are living relatives of dinosaurs. In both the modern and ancient samples, the peptide sequences were the same as those found in blood vessels, the scientists said.
"This study is the first direct analysis of blood vessels from an extinct organism, and provides us with an opportunity to understand what kinds of proteins and tissues can persist and how they change during fossilization," Cleland said in a statement. "This will provide new avenues for pursuing questions regarding the evolutionary relationships of extinct organisms, and will identify significant protein modifications and when they might have arisen in these lineages."
Now that researchers have sequenced a large number of bird and crocodilian genomes, there should be more information about the proteins made by these creatures. This data may, in turn, help researchers study dinosaur proteins that have survived over millions of years, Cleland said.
"Part of the value of this research is that it gives us insight into how proteins can modify and change over 80 million years," Mary Schweitzer, a molecular paleontologist at North Carolina State University and co-author of the paper, said in the statement. "It tells us not only about how tissues preserve over time, but gives us the possibility of looking at how these animals adapted to their environment while they were alive."