Morphological Convergence in Forest Microfungi Provides a Proxy for Paleogene Forest Structure

Amber, fossilized plant resin from gymnosperms and angiosperms, is renowned for preserving a wide range of organisms in microscopic fidelity. These so-called amber inclusions comprise many groups of organisms, ranging from bacteria to arthropods and vertebrates. Calicioid lichens and fungi, which are from now on referred to as “calicioids,” constitute a diverse group of tiny ascomycetes with superficially similar, usually well-stalked ascomata and which often accumulate mature ascospores on top of the apothecial disk to form a true mazaedium. The aim of this study is to use all available information on the morphology and ecology of extant calicioids to reconstruct the substrate and habitat ecology of known fossil calicioids and then to use this information to open new insights into the stand structure and ecological conditions of European Paleogene amber forests. First, we introduce the morphology of extant calicioids and demonstrate that their structural features are intimately linked to habitat ecology and are instrumental for successful dispersal; we also explain the conspicuous morphological convergence between phylogenetically distant calicioid fungi. Then, we show that the adaptive traits of calicioids have not changed since at least the Eocene, and argue that their fundamental niches also have remained unchanged. Finally, we summarize what the diversity and relative abundance of fossil calicioids in amber tells us about the ecological conditions that once prevailed in European amber forests.Peer reviewe

Plastome data reveal multiple geographic origins of Quercus Group Ilex

Nucleotide sequences from the plastome are currently the main source for assessing taxonomic and phylogenetic relationships in flowering plants and their historical biogeography at all hierarchical levels. One major exception is the large and economically important genus Quercus (oaks). Whereas differentiation patterns of the nuclear genome are in agreement with morphology and the fossil record, diversity patterns in the plastome are at odds with established taxonomic and phylogenetic relationships. However, the extent and evolutionary implications of this incongruence has yet to be fully uncovered. The DNA sequence divergence of four Euro-Mediterranean Group Ilex oak species (Quercus ilex L., Q. coccifera L., Q. aucheri Jaub. & Spach., Q. alnifolia Poech.) was explored at three chloroplast markers (rbcL, trnK/matK, trnH-psbA). Phylogenetic relationships were reconstructed including worldwide members of additional 55 species representing all Quercus subgeneric groups. Family and order sequence data were harvested from gene banks to better frame the observed divergence in larger taxonomic contexts. We found a strong geographic sorting in the focal group and the genus in general that is entirely decoupled from species boundaries. High plastid divergence in members of Quercus Group Ilex, including haplotypes shared with related, but long isolated oak lineages, point towards multiple geographic origins of this group of oaks. The results suggest that incomplete lineage sorting and repeated phases of asymmetrical introgression among ancestral lineages of Group Ilex and two other main Groups of Eurasian oaks (Cyclobalanopsis and Cerris) caused this complex pattern. Comparison with the current phylogenetic synthesis also suggests an initial high- versus mid-latitude biogeographic split within Quercus. High plastome plasticity of Group Ilex reflects geographic area disruptions, possibly linked with high tectonic activity of past and modern distribution ranges, that did not leave imprints in the nuclear genome of modern species and infrageneric lineages

Early Miocene pollen and spores from western Jylland, Denmark - environmental and climatic implications

A palynological analysis of a Lower Miocene cored section from Sonder Vium in western Jylland, Denmark, provides new data regarding the vegetation and climate during the earliest Neogene. Most samples yielded well-preserved palynomorphs. Terrestrial pollen and spores dominate, with lesser proportions of dinoflagellates. A fluvial input into the marine setting is corroborated by the presence of freshwater algae, indicating, an inner-neritic setting. A level containing comparatively abundant dinoflagellate cysts probably represents a transgressional event. The late Aquitanian age of the sequence as suggested by previous studies is supported by the composition of the palynoflora, e.g., by the presence of Ephedripites, Platycarya, and the relatively frequent occurrence of Engelhardtia. The pollen record is dominated by Taxodiaceae-Cupressaceae suggesting that swamp forests dominated the onshore region, which is consistent with previous results from central and northern Europe. Besides Taxodium, the swamp forest also contained angiosperm taxa such as Myricaceae, Nyssa, Betula, and Alnus. Elevated or better drained hinterland areas hosted a diverse mesophytic forest, with a ground cover of reeds, sedges and pteridophytes. Abundant pollen taxa derived from mesophytic forests indicates the presence of evergreen conifers, such as Pinus, Sequoia and Sciadopitys, and deciduous angiosperms, including Fagus and Quercus. A decrease in relative abundances of thermophilous elements such as Arecaceae (palms), Ilex, Mastixiaceae and Engelhardtia, in the middle part of the studied succession indicates a possible correlation to the late Aquitanian climatic deterioration. The composition of the palynological assemblages including widely distributed Taxodium swamps, suggests a warm, frost-free temperate climate during the Aquitanian in Denmark