Fluorescent colour patterns in the basal pectinid <i>Pleuronectites</i> from the Middle Triassic of Central Europe: origin, fate and taxonomic implications of fluorescence

UV light-induced fluorescence is widely used as a key to reveal residual shell colour patterns of Neogene and Palaeogene molluscs. However, only few examples fluorescent are known from Mesozoic marine shells little about the nature in fossils. Here, reveals previously unseen abundance diversity basal pectinid Pleuronectites laevigatus Middle Triassic Muschelkalk Central Europe. In addition variations radial bands, multitude zigzag zigzag-related was found. The comparable modern pectinids interpreted pattern polymorphism. Raman spectra indicated preservation organic pigments with aromatic moieties. properties P. other Germany France described detail, suggesting that due colourless diagenetic products pigments, not fossil themselves. A remarkable feature presence different colours. Because gradual shift yellow red decreasing intensity finally non-fluorescent observed, which correlates provenance specimens, reflect differences history. results show molluscs, especially may be affected by diagenesis should caution for taxonomic purposes.