Dispersed pollen and calyx remains ofDiospyros(Ebenaceae) from the middle Miocene “Plant beds” of Søby, Denmark

Abstract

Diospyros is a large genus of woody flowering plants with a predominantly subtropical and tropical modern distribution. Fossils attributed to Diospyros are mainly leaf impressions from Cretaceous and Cenozoic strata across the Northern Hemisphere. However, it is difficult to assign such fossils to Diospyros because genus-diagnostic leaf characteristics remain to be identified. Unequivocal fossil records of Diospyros are few, including staminate flowers with in situ pollen from the late Eocene of South Australia and dispersed pollen from Cenozoic strata in the Northern Hemisphere. Here, we investigated dispersed pollen and calyx remains from Miocene deposits of Denmark using a combined scanning electron/light microscopy approach. Tricolporate, relatively large pollen with lalongate pori and long bow-shaped colpi and a distinctive micro/nanorugulate exine ornamentation together with persistent 4-lobed flower calyces allow unambiguous identification of the genus. Based on the large size of the calyx, we describe a new fossil-species of Diospyros. Further, a review of the fossil pollen record of Diospyros shows that, in addition to the Australian record, the genus was present in South China, western North America and Europe during the Eocene and in East and South Africa and Central Asia during the Oligo-Miocene. Although still scanty, the pollen record can contribute vital information for timecalibrated molecular phylogenies to resolve conflicting biogeographic inferences. A thorough description of the historical biogeography of Diospyros is still in its infancy. While we initiate such a study here, development of a comprehensive picture will require further studies of dispersed pollen grains with high taxonomic resolution.

Advances in Swedish palaeontology; the importance of fossils in natural history collections - The Department of Palaeobiology at the Swedish Museum of Natural History

“…The excellently preserved and well curated fossil specimens in the collections at the department of Palaeobiology at the NRM are no exception. As shown in this volume, new methods applied to old and new collections can provide a whole new perspective on animals (Devaere & Skovsted 2021; et al 2021;Krüger et al 2021;Schwarzhans & Mörs 2021;Skovsted et al 2021), plants (Denk & Bouchal 2021a;Peng et al 2021;Steinthorsdottir et al 2021) and fungi (Ivarsson et al 2021) of past eras, or their crucial interactions (McLoughlin et al 2021a(McLoughlin et al , 2021b. Millions of specimens are available at the NRM and are ready to be placed in their proper context by new innovative studies.…”

“…Despite the lack of plant remains from the mid-Cenozoic from Sweden, Denmark hosts extensive, fossiliferous deposits representing this time interval (Larsson et al 2011) and the Department of Palaeobotany has a well-curated collection from the Søby-Fasterholt area in Central Jutland, Denmark (Friis 1985;Denk & Bouchal 2021a, 2021b and references therein). The successions have been dated to 15-17 million years (Rasmussen et al 2010), equivalent to the Miocene Climatic Optimum.…”

“…The successions have been dated to 15-17 million years (Rasmussen et al 2010), equivalent to the Miocene Climatic Optimum. In a study by Denk & Bouchal (2021a; this issue), fossilised persimmon fruits (Diospyros) and pollen from the Søby-Fasterholt successions are described. The fossils are exceptionally well preserved with intact calyces, and the results also indicate that the Danish fossil persimmon belongs to a Northern Hemisphere clade that possibly extends back to the Eocene.…”

The Genus Diospyros: A Review of Novel Insights into the Biological Activity and Species of Mozambican Flora

“…are tree shrubs or subshrubs with entire alternate leaves, solitary flowers, and fleshy fruits (berries) with usually two or more seeds. The characteristics of the leaves and flowers of these species are often used to identify fossil casts [5][6][7].…”