ABBERANT CLASSOPOLLIS POLLEN REVEAL EVIDENCE FOR ENVIRONMENTAL MUTAGENESIS IN CONIFERS DURING THE END-TRIASSIC MASS EXTINCTION
We show for the first time new and compelling evidence for genetic mutations in the pollen record of conifers during the Triassic – Jurassic mass extinction. We demonstrate the presence of aberrant pollen clusters and an exceptional variability in pollen size of the conifer pollen Classopollis. Our data imply that this group of conifers produced unreduced pollen, which is regarded as one of the main mechanism of polyploid formation in modern land plants. Our data represents the oldest evidence for unreduced pollen yet documented from the fossil record of vascular plants. We suggest that that polyploidy may have reduced the extinction risk of these conifers during the Tr-J biotic crisis. Notably this conifer group appears to be hardly affected by environmental stress and becomes a very dominant vegetation element in the aftermath of the mass-extinction.