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New Fagaceous pollen taxa from the Miocene Søby flora of Denmark and their biogeographic implications
Author(s) -
Denk Thomas,
Bouchal Johannes M.
Publication year - 2021
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/ajb2.1716
Subject(s) - fagaceae , biology , taxon , biogeography , paleobotany , pollen , ecology , evergreen , subarctic climate , phytogeography , paleontology , late miocene , massif , structural basin , biochemistry , plant development , gene
Abstract Premise The Fagaceae comprise around 1000 tree species in the Northern Hemisphere. Despite an extensive fossil pollen record, reconstructing biogeographic patterns is hampered because it is difficult to achieve good taxonomic resolution with light microscopy alone. We investigate dispersed pollen of Fagaceae from the Miocene Søby flora, Denmark. We explore the latitudinal gradient in Fagaceae distribution during the Miocene Climatic Optimum (MCO) in Europe and the Northern Hemisphere to compare it with the Eocene Warmhouse and the present. Methods We investigated dispersed pollen using light and scanning electron microscopy. We assessed biogeographic patterns in Fagaceae during two warm periods in Earth history (MCO, Eocene) and the present. Results Eight species of Fagaceae were recognized in the Søby flora. Of these, Fagus had a continuous Mediterranean to subarctic distribution during MCO; Quercus sect. Cerris and castaneoids had northern limits in Denmark, and evergreen Quercus sect. Ilex in Central Europe. In a northern hemispheric context, Fagus and sections of Quercus had more northerly distribution limits during Eocene and MCO with maximum northward extensions during Eocene ( Fagus , castaneoids) or Oligo‐Miocene ( Quercus sects. Cerris and Ilex ). The known distribution of the extinct Tricolporopollenites theacoides during MCO included Central Europe and East China, while this taxon thrived in South China during Eocene. Conclusions More northerly distributions during MCO and Eocene probably were determined by temperature. In contrast, fossil occurrences in areas that are arid or semi‐humid today were determined by maritime conditions in these areas (western North America, Central Asia) during the Cenozoic.