Editing The Pliocene flora of Frankfurt am Main in Germany

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It is suggested a [[late Pliocene]] age ([[Reuverian]]) for this flora. [[Palynoflora]]s from drill cores in the surroundings of [[Frankfurt am Main]] and [[Hanau]] also suggests a late Pliocene age. The [[Pliocene]] flora of [[Frankfurt am Main]] described by [[Karl Mädler]] during the first half of the [[twentieth century]] is a key flora for the European Pliocene. In total 16 [[gymnosperm]] species in 15 genera and 73 [[angiosperm]] species (of which 15 could not be assigned to a genus) in 40 genera are recognised in the leaf record. Main characteristics of the flora are the high diversity of conifers, deciduous [[angiosperm]] genera such as [[Eucommia]], [[Magnolia]] and [[Sassafras]], a diverse assemblage of exclusively deciduous [[Fagaceae]], including six species of oaks, the high diversity of [[Rosaceae]], whereas evergreen taxa are shrubs typical of the understorey as [[Buxus]], [[Ilex]], [[Pachysandra]], [[Prunus lusitanica]] and [[Viscum]]. These features indicate cool temperate climatic conditions comparable to present-day [[Lugano]] in southern [[Switzerland]]. The flora shows a strong biogeographic link with [[East Asia]], surprisingly high levels of Pliocene endemisms and that the European flora was more diverse in woody species shortly before the onset of the major [[Pleistocene]] glaciations than today. The early part of the Pliocene (5.3–3.6 Ma) was characterised by warm conditions (ca. 3&nbsp;°C higher global surface temperatures) and higher sea levels (10–20 m) and slightly higher CO2 concentrations. During the second part of the Pliocene, gradual cooling culminated in a significant intensification of northern hemispheric glaciation at ca. 2.75 Ma. Despite this, many exotic taxa persisted as relicts from older epochs and modern diversity patterns of trees and shrubs across the Northern Hemisphere were established only during and after the major Pleistocene glaciations.<ref>The Pliocene flora of Frankfurt am Main, Germany: taxonomy, palaeoenvironments and biogeographic affinities by Zlatko Kvaček, Vasilis Teodoridis & Thomas Denk - Palaeobiodiversity and Palaeoenvironments, pages 647–703 (2020) - Springer Link - https://doi.org/10.1007/s12549-019-00391-6</ref><ref>Mädler, Karl. Die pliozäne flora von Frankfurt am main. Vol. 446. Alexander Doweld, 1939.</ref><ref>On the fossil history of Pseudotsuga Carr. (Pinaceae) in Europe by Lutz Kunzmann - Palaeobiodiversity and Palaeoenvironments 94(2):39 3-409, June 2014 - Senckenberg Natural History Collections - https://doi.org/10.1007/s12549-014-0156-x</ref>

==History of the fossil findings==
Fossil plant remains had been discovered in the excavation pit of the Höchst lock in 1884, a sandy clay layer, many more fossil seeds, fruits and leaves were uncovered in 1885 during the construction of the Frankfurt water clarifier near Niederrad. The works on these plant fossils were edited by GEYLER & KINKELIN and their results were published in the 15th volume of the Treatises of the Senckenbergische Naturforschende Gesellschaft in 1887.<ref>Oberpliocän-Flora aus den Baugruben des Klärbeckens bei Niederrad und Schleuse bei Höchst a M. T. Geyler F. Kinkelin. (Frankfort, 1887.)</ref>

==Geography==
{{More citations needed}}
The fossil leaves comprising the flora have been recovered in [[Niederrad]] which is a quarter of [[Frankfurt am Main]], [[Germany]]. It is part of the Ortsbezirk Süd and is subdivided into the Stadtbezirke Niederrad-Nord, Niederrad-Süd and the new Niederrad-West. Niederrad is bordered in the north by the [[River Main]], in the west by the A5 Autobahn, in the south by the Main Railway and Flughafenstraße, and in the east by the former Niederrad Racecourse, Kennedyallee and the Main-Neckar Railway.

==Fossil plant species so far described from the deposits==

=== [[Gymnosperms]] ===

[[Ginkgoaceae]]

*†[[Ginkgo]] adiantoides, several leaves.
*[[Cupressaceae]]

:*†''[[Glyptostrobus europaeus]]'', 2 leafy shoots
 
:*†''[[Taxodium]] dubium'' leafy shoots

:*†''[[Sequoia (genus)|Sequoia]] abietina'', leafy shots

:*†''[[Metasequoia]] langsdorfii'', synonym: ''Sequoia langsdorfii''.
 
:*†''[[Cryptomeria]] rhenana'', several twigs, very similar to [[Cryptomeria japonica]].

:*''[[Calocedrus]]'' sp.

*[[Sciadopityaceae]]

:*†''[[Sciadopitys]] tertiaria'', (abaxial cuticle).

*[[Taxaceae]]

:*†''[[Cephalotaxus]] pliocaenica'', several needles

:*''[[Taxus baccata]]'', needle fragments.

:*''[[Torreya nucifera]]'', needles and seeds.

*[[Pinaceae]]

:*''[[Abies alba]] fossilis'' synonym ''Abies pectinata fossilis'', a needle and one seed cone.
:*†''[[Abies]] sclereidea'', two needle fragments.

:*†''[[Cathaya]] loehri'', orginally named :''[[Keteleeria]] loehri''.

:*†''[[Picea]] omoricoides'', several needles, like [[Picea omorika]], .

:*''[[Pinus sylvestris]]'' synonym ''Pinus montana'', one seed cone.
:*†''[[Pinus]] timleri'', cones.

:*†''[[Pseudotsuga]] kinkelinii'', needle leaves and cones.
:*†''[[Pseudotsuga]] sclereidea'', two needle fragments, most like ''[[Pseudotsuga menziesii]]''.

:*†''[[Thuja]] pliocaenica''
:*†''[[Tsuga]] europaea'', 15 needles, most like [[Tsuga caroliniana]].

=== [[Angiosperms]], [[dicots]] ===

*[[Magnoliaceae]] 
 
:*†''[[Magnolia]] liblarensis'', leaf fragment. 
:*†''[[Magnolia]] waltheri'', incomplete leaf.

*[[Lauraceae]]

:*†''[[Sassafras]] ferretianum'', a complete leaf.

*[[Santalaceae]]

:*†''[[Viscum]] miquelii'', one leaf.

:*†''[[Viscum]] pliozänicum'', leaf and epidermal preparation.

*[[Buxaceae]]

:*†''[[Buxus]] pliocaenica'', one entire leaf and a leafy shot.

:*''[[Buxus sempervirens]] fossilis'', leaves and fruit cupules.

:*†''[[Pachysandra]] europaea'', one incomplete leaf.
 
*[[Cercidiphyllaceae]]

:*†''[[Cercidiphyllum]] crenatum'', a leaf fragment, similar to ''[[Cercidiphyllum japonicum]]''.

*[[Hamamelidaceae]]

:*†''[[Parrotia]] pristina'' an incomplete leaf, closely related to [[Parrotia persica]].

:*†''[[Corylopsis]] urselensis''

*[[Altingiaceae]]

:*†''[[Liquidambar]] europaea'', an incomplete leaf, close to [[Liquidambar orientalis]].
:*†''[[Liquidambar]] pliocaenicum'' (infructescences).

*[[Juglandaceae]]

:*''[[Carya ovata]]'' fruits.
:*†''[[Carya]] globosa'' one nut.
:*†''[[Carya]] longicarpa''
:*''[[Carya tomentosa]]'' fossilis (synonym Carya alba fossilis), fruits.

:*''[[Juglans cinerea]] fossilis'', several nuts.

:*†''[[Pterocarya]] paradisiaca'', a complete leaflet.

*[[Fagaceae]]

:*''[[Castanea sativa]]'', a leaf fragment.

:*†''[[Fagus]] kraeuselii'', complete leaves, closest similarity is with the extant East Asian ''[[Fagus crenata]]'' and ''[[Fagus hayatae]]''.

:*†''[[Quercus]] kubinyii'', (fragmentary leaf).
:*†''[[Quercus]]  praecastaneifolia'' (obate leaf. 
:*†''[[Quercus]] roburoides'', lobate leaves, it resembles closly ''[[Quercus petraea]]'' and ''[[Quercus dalechampii]]'', 
:*†''[[Quercus]] pseudocastanea '', complete and incomplete leaves. have similarities to ''[[Quercus griffithii]]'' and ''[[Quercus dentata]]''.

*[[Betulaceae]]

:*†''[[Alnus]] gaudinii '', (complete and incomplete leaves), the nearest living relative for this fossil species is the Caucasian alder, ''[[Alnus subcordata]]'' that differs from the fossil species by slightly wider leaves.

:*†''[[Betula]]  similis'', complete and incomplete leaves, it is similar to ''[[Betula platyphylla]]''.  
:*†''[[Betula]] longisquamosa'', fruits.

:*†''[[Carpinus]] grandis'' (leaf and fruits), very similar to ''[[Carpinus betulus]]''.
:*†''[[Carpinus]] uniserrata '', a complete leaf, similar to ''[[Carpinus caroliniana]]'' produces similar but wider and coarsely serrate leaves.

:*''[[Corylus avellana]]'' (fruits).
:*†''[[Corylus]] kolakovskyi'', (complete and incomplete leaves), very similar to ''[[Corylus maxima]]'' and ''[[Corylus avellana]]''.

*[[Cannabaceae]]

:*†''[[Celtis]] trachytica'', (incomplete leaf).

*[[Ulmaceae]]

:*†''[[Planera]] ungeri'', leaves.

:*†''[[Ulmus]] carpinoides'', complete leaf, quite similar to ''[[Ulmus minor]]''.
:*†''[[Ulmus]] pyramidalis'', complete leaf.

:*†''[[Zelkova]] zelkovifolia'', complete leaves.

*[[Cucurbitaceae]]

:*''[[Trichosanthes]]'' sp., (complete leaf).

*[[Salicaceae]]

:*†''[[Populus]] balsamoides'', a complete leaf. 
:*†''[[Populus]] canescentoides '', complete leaves.
:*†''[[Populus]] gregorii'', incomplete leaves.
:*†''[[Populus]]  populina'', complete and incomplete leaves.

:*†''[[Salix]] lavateri '', complete and incomplete leaves.

*[[Sapindaceae]]
 
:*†''[[Acer (plant)|Acer]] brachyphyllum''  similar to the extant ''[[Acer obtusifolium]]''.
:*†''[[Acer (plant)|Acer]] dombeyopsis'' , (partial leaves and abaxial cuticle). 
:*†''[[Acer (plant)|Acer]] integerrimum'', an incomplete leaf.
:*†''[[Acer (plant)|Acer palaeo-miyabei]]''
:*''[[Acer platanoides]]'' aff.
:*†''[[Acer (plant)|Acer]] pyrenaicum'', a complete leaf.
:*†''[[Acer (plant)|Acer]]  subcampestre'', a complete leaf.
:*†''[[Acer (plant)|Acer]] viburnoides'', a complete leaf, similar to ''[[Acer heldreichii]]''.  
:*†''[[Acer (plant)|Acer]] vitiforme'', a complete leaf.
 
:*†''[[Aesculus]] hippocastanoides'', complete leaflets, very similar to ''[[Aesculus hippocastanum]]''.

*[[Meliaceae]]

:*†''[[Toona]]'' sp., (complete leaflet), similar to ''[[Toona sinensis]]''. 
 
*[[Rosaceae]]

:*†''[[Crataegus]] pentagynoides'', several entire leaves, similar to the extant ''[[Crataegus pentagyna]]''.

:*''[[Malus]]'' sp., a complete leaf with serrulate margin.

:*''[[Sorbus aucuparia]]'' aff., a complete leaflet.

:*''[[Spiraea]] trichocarpa'' aff., an entire leaf.

:*''[[Prunus lusitanica]]'' 
:*†''[[Prunus]] aviifolius''
 
*[[Fabaceae]]

:*†''[[Gleditsia]] pliocaenica'', the modern ''[[Gleditsia caspica]]'' Desfontaines produces similar foliage and might be the closest extant relative of the fossil taxon, but differs from ''Gleditsia caspica'' in broader asymmetrically ovate leaflets and a distinctly crenulate lamina.

*[[Malvaceae]]

:*†''[[Craigia]] lobata'', a complete leaf.

:*†''[[Hibiscus]]'' sp., a complete leaf and an abaxial cuticle with trichomes, similar to the extant ''[[Hibiscus mutabilis]]''.
 
:*''[[Tilia]]''? sp., isolated bracts.

*[[Eucommiaceae]]

:*†''[[Eucommia]] europaea''
:*†''[[Eucommia]] szaferi'', one leaf and one epidermal preparation.

*[[Styracaceae]]

:*†''[[Styrax]] obovatum'', two seeds.

*[[Theaceae]]

:*†''[[Stewartia]] europaea'' synonym ''Stuartia europaea'', one fruitlet.
 
*[[Aquifoliaceae]]

:*''[[Ilex aquifolium]]'', one entire leaf and several leaf remains.
:*†''[[Ilex]] geissertii'', an abaxial cuticle.

*[[Oleaceae]]

:*†''[[Fraxinus]] angusta'' (abaxial cuticle with peltate trichomes).

*[[Ebenaceae]]

:*''[[Diospyros]]'' sp?

===[[Angiosperms]], [[monocots]]===

*[[Smilaceae]]

:*''[[Smilax]]'' sp.

*[[Potamogetonaceae]]

:*†''[[Potamogeton]] medicagoides''


==References==
{{Reflist}}

[[Category:Pliocene]]
[[Category:Paleobotany]]
[[Category:Frankfurt]]
[[Category:Fossils of Germany]]
[[Category:Paleontological sites]]