75 million year-old dinosaur cells found
The remains of blood cells and fibrous tissues have been found preserved in a collection of dinosaur fossils by UK scientists.
For more than a decade, evidence has been mounting that fossils are not just a rocky facsimile of the life form they resemble but instead tissues from the original organism may be preserved too.
In 2005, North Carolina State University researcher Mary Schweitzer controversially announced that she had managed to extract soft tissues and even signs of blood cells from the 68 million year old remains of a T.rex.
Now scientists at Imperial College London, working on eight different dinosaur fossils including 75 million year old leg bones and a claw, have shown that they too could detect traces of preserved tissue and blood cells in their specimens.
Critically, the samples studied by Susannah Maidment and her colleagues were poorly preserved specimens selected for the study on the basis of their low value. The findings, announced this week in Nature Communications, suggest that the presence of preserved organic materials inside fossilised remains may be a great deal more common than first thought.
The team analysed their specimens in two ways. Using an electron microscope, they were able to spot structures bearing a striking resemblance to the red blood cells of an emu, which they also tested as a control. Emu blood is a valid comparison, because birds are the dinosaurs closest living relatives. The microscope study also revealed fibrous tissue with a characteristic "banding" pattern corresponding to the protein collagen.The regular presence of a particular molecule in collagen gives it a stripey pattern under the electron microscope, which the team saw in their images.
The samples were also analysed using a technique called time-of-flight secondary ion mass spectrometry (ToF-SIMS), which uses a stream of high-energy particles to dislodge molecules from a surface and feed them into a mass spectrometer, which can identify chemicals on the basis of their size.
Spikes appeared on the graph corresponding to some of the common collagen protein building blocks. Similar analysis on the areas seen to contain blood cells also showed molecules with signatures of cholesterol, ceramide and folic acid, which matched the profile produced by emu blood.
Given the poor state of preservation of the material they studied, these results suggest, the team speculate, that preservation of organic remains inside fossil remains is far more common than had first been believed, and may be the rule rather than the exception.
Moreover, the results seem to suggest that, in fact, you can get blood out of a stone!