Researchers have found pigments in twelve million-year-old fossilized snail shells. These are the first pigments of the chemical polyene group to be found in fossils, preserved almost unchanged.
Snail shells are often colorful and have striking patterns. This is due to pigments produced in the snail’s specialized cells and stored in varying concentrations in the shell. Fossil shells, on the other hand, are often pale and inconspicuous because their pigments are very delicate and have already decomposed. Remnants of ancient color patterns are therefore very rare.
This makes this new discovery by researchers from the University of Göttingen and the Natural History Museum Vienna (NHMW) even more surprising: The researchers found pigments in twelve million-year-old fossilized snail shells. These are the first pigments of the chemical polyene group to be preserved almost unchanged and found in fossils.
Paleontologists have found snail shells belonging to the superfamily Cerithioidea in Burgenland, Austria. These snails lived on the shores of the tropical sea twelve million years ago.
“At first it was unclear whether the reddish-colored patterns came from the original crust or whether they were formed later in the process by sediment,” says Professor Mathias Harzhauser, who was part of the discovery team. But the researchers have solved the mystery.
Pigments were analyzed using Raman spectroscopy. This technique requires shining laser light on samples. The scattered light reflected from the sample can be used to clearly identify chemical compounds.
Researchers have detected pigments belonging to the polyene group of chemicals in fossilized shells. These are organic compounds containing the famous “carotenoids” that produce the vibrant red, orange and yellow colors in, for example, birds’ feathers, carrots and egg yolks.
Dr. Klaus Wolkenstein, who led the research and has been studying the chemistry of fossil pigments for many years, said, “Normally, the best we can hope for after such a long time is that traces of the degradation of these chemicals remain. But if they had degraded, these compounds would have lost their color. So it was really surprising to discover these pigments preserved almost intact in twelve-million-year-old fossils.”
University of Göttingen. February 9, 2024.
Klaus Wolkenstein, Burkhard C. Schmidt, Mathias Harzhauser. 2024. Detection of intact polyene pigments in Miocene gastropod shells. Palaeontology.
