A large team of American scientists has found evidence of blood vessel-like structures in the fossil of Brachylophosaurus canadensis, a mid-sized duck-billed dinosaur that lived in what is now Montana around 80 million years ago.

Research team leader Dr Tim Cleland of the University of Texas at Austin and his colleagues demineralized a fragment of Brachylophosaurus canadensis leg bone.

They then analyzed the demineralized bone with mass spectroscopy and found several distinct proteins from the cellular components of the blood vessels.

One of these proteins, called myosin, is found in the smooth muscles associated with the walls of blood vessels.

Dr Cleland and co-authors confirmed their results by performing the same process with bones from chicken and ostrich, which are living relatives of the dinosaurs.

In both the modern and ancient samples, peptide sequences matched those found in blood vessels.

“Peptide sequencing of Brachylophosaurus canadensis blood vessel extracts is consistent with peptides comprising extant archosaurian blood vessels and is not consistent with a bacterial, cellular slime mold, or fungal origin,” the scientists wrote in a paper published November 23 in the Journal of Proteome Research.

“When all data are taken into consideration, the most parsimonious explanation is that these vessels, derived from demineralized dinosaur bone, are endogenous,” they said.

“These data open the door for molecular characterization of biological components of other long-extinct organisms.”

Dr Cleland added: “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.”

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Timothy P. Cleland et al. Mass Spectrometry and Antibody-Based Characterization of Blood Vessels from Brachylophosaurus canadensis. J. Proteome Res., published online November 23, 2015; doi: 10.1021/acs.jproteome.5b00675