Preservation of hypericin and related polycyclic quinone pigments in fossil crinoids

Abstract

The fringelite pigments, a group ofphenanthroperylene quinones discovered in purple coloured specimens of the Upper Jurassic crinoid Liliocrinus, demonstrate exceptional preservation of organic compounds in macrofossils. Here we report the finding of hypericin and related phenanthroperylene quinones in Liliocrinus munsterianus from the original 'Fringeli' locality and in the Middle Triassic crinoid Carnallicrinus carnalli. Our results show that fringelites in fact consist ofhypericin and closely related derivatives and that the stratigraphic range of phenanthroperylene quinones is much wider than previously known. The fossil occurrence of hypericin indicates a polyketide biosynthesis of hypericin-type pigments in Mesozoic crinoids analogous to similar polyketides, which occur in living crinoids. The common presence of a characteristic distribution pattern of the fossil pigments and related polycyclic aromatic hydrocarbons further suggests that this assemblage is the result of a stepwise degradation of hypericin via a general diagenetic pathway.