16 May 2012
A new research study shows that pigment (colour) in extinct animals can be preserved for over 50 million years. Despite their old age, the pigment molecules correspond closely to the equivalent pigment in modern-day animals. “With the help of the molecules, we now have a time machine that enables us to revisit and study ancient animals with the same precise instruments and tools that we use to study living animals”, says Per Uvdal, Professor of Chemical Physics at Lund University and MAX-lab in Sweden.
Today we imagine dinosaurs and other ancient animals as perhaps green or brown. But what did they actually look like? It was mostly pure guesswork until a couple of years ago when what looked like traces of pigment were found in very well-preserved feathers from a fossil of a small dinosaur. The question was whether it really was pigment or something completely different, like bacteria. Until now there has been a lack of strong evidence for the preservation of pigment across geological periods.
Now a group of researchers have succeeded in finding and studying well-preserved pigment in an eye from a 54-million-year-old fossilised fish found in Denmark. Behind the sensational findings are researchers from Lund University, MAX-lab and the SP Technical Research Institute of Sweden.
The research team has been able to identify organelles, or cell components, that bear a strong resemblance to melanosomes. A melanosome is composed of melanin, the pigment that protects us from the sun’s rays. Using hypersensitive measuring instruments, the research team has clearly shown that the ancient melanosomes in the fish eye not only look like melanosomes, but are also made of melanin, the same as in modern-day animals. The measurements show for the first time that the melanin molecules in the fish eye and in modern samples have very similar structures despite the 50 million year age difference.
However, perhaps even more importantly, in Uvdal’s view, the discovery shows that biomolecoles that were found in the animal when it was alive can be preserved across huge expanses of time given the right conditions. There has long been doubt as to whether this was possible at all. The discovery also gives previous speculations about the colour of the dinosaurs’ feathers a solid foundation in molecular biology.
The article was published in the journal Nature Communications. The researchers behind the discovery are Dr Johan Lindgren (Lund University), Prof. Per Uvdal (MAX-lab), Prof. Peter Sjövall (SP, Borås), Prof. Dan E. Nilsson (Lund University), Dr Anders Engdahl (MAX-lab), Dr Bo Pagh Schultz (Salling Museum) and Prof. Volker Thiel (University of Göttingen).