This image had never been seen by the human eye, until our team, in this case led by Dr Roy Wogelius and graduate student Nick Edwards, used state-of-the-art infra-red technology to reveal and map the fossilized soft tissue from this beautifully-preserved reptile.
These infra-red maps are backed up by the first ever element-specific maps of organic material in fossil skin generated using X-rays at the Stanford synchrotron in the USA, working in collaboration with Dr Uwe Bergmann at SLAC. This is the same technology that was used to hed light on the chemical ghost of feathers preserved in Archaeopteryx, published again by our team last year in PNAS.
Chemical details are clear enough that we able to propose how this exceptional preservation occurs. When the original compounds in the skin begin to break down they form chemical bonds with trace metals, and under exceptional conditions these trace metals act like a ‘bridge’ to minerals in the sediments. This protects the skin material from being washed away or decomposing further...literally a fossiliferous hard-hat!
Roy is as chuffed as ever about the results, saying, “The mapped distributions of organic compounds and trace metals in 50 million year old skin look so much like maps we’ve made of modern lizard skin as a check on our work, it is sometimes hard to tell which is the fossil and which is fresh.”
Roy is also keen to point out to the palaeontological community that, “These new infra-red and X-ray methods reveal intricate chemical patterns that have been overlooked by traditional methods for decades.”
The new images are compelling, and represent the next step in our research programme to use modern analytical chemistry and 21st century techniques to understand how such remarkable preservation occurs, and work towards discovering more on the fossil chemistry preserved in ancient life.
These new results imply that trace metal inventories and patterns in ancient reptile skin, even after fossilisation, can indeed be compared to modern reptiles. The infra-red light causes sweet vibrations in the fossilized skin, and a map of where these vibrations occur can be obtained from a fossil by using a trick: a tiny crystal (like an old phonograph record stylus) which moves from point-to-point in a programmable grid across the surface.
At each point where the tiny crystal touches the fossil, an infra-red beam that shines through the crystal reflects off of the crystal base, but a small amount of the beam probes beyond the interface- and if organic compounds are present, they absorb portions of the beam and change the reflected signal.
This has allowed our team to non-destructively map large fossils which do not themselves transmit or reflect the beam – a revolutionary process for paleontologists.
Nick Edwards, first author on the publication, said: “The ability to chemically analyse rare and precious fossils such as these without the need to remove material and destroy them is an important and long overdue addition to field of palaeontology.
Here physics, palaeontology and chemistry have collided to yield incredible insight to the building blocks of fossilized soft tissue. The results of this study have wider implications, such as understanding what happens to buried wastes over long periods of time. The fossil record provides us with a long-running experiment, from which we can learn in order to help resolve current problems.
You can learn more about this discover on a video podcast with myself and Roy! Just click HERE