Qualitative LM and SEM study of the Messel palynoflora: part I. Algae to Vitales.

In this first report on the re-investigation of the Eocene Messel palynoflora using combined light- and scanning electron microscopy, comprising Algae to Vitales, it is shown that this epic paleoflora can still provide new insights into the ancient ecosystem prevailing at that time. Applying this combined single-grain method on the palynomorphs enabled us to identify several new floral elements represented in the palynoflora, as well as to revise previous spore/pollen classifications, resulting in a higher taxonomic resolution of the microflora. So far, we have discovered three different algae remains, 28 spore types, and pollen from seven different gymnosperms and 26 unique angiosperms. Some of the new taxa include Lycopodiaceae, Cycadales, Stratiotes (Hydrocharitaceae), and Poaceae. The spore/pollen flora was compared to the meso/macroflora, revealing the importance of combining meso/macrofossil records with state-of-the-art microfossil analyses for a more holistic representation of the paleoflora. This is reflected in the number of taxa only occurring in the microflora (ten families) versus that of the meso/macroflora (18 families). Comparing the results from this qualitative combined light- and scanning electron microscopy study to classical quantitative light microscopy methods already suggests that the combined method provides a higher diversity of spore/pollen taxa. Still, potential floral newcomers could be missed in such single sample investigations that are otherwise detected in the classic up-trough section analyses. [ABSTRACT FROM AUTHOR]