Plant Diversity of The Mid Silurian (Lower Wenlock, Sheinwoodian) Terrestrial Vegetation Preserved in Marine Sediments from The Barrandian Area, The Czech Republic

Abstract

<jats:title>Abstract</jats:title> <jats:p>Plant mega- and microfossils are described from the middle Sheinwoodian of the Barrandian area. The material comes from the Loděnice locality and the same horizon as the earliest unequivocal land plant, Cooksonia barrandei LIBERTÍN, J.KVAČEK, BEK, ŽÁRSKÝ et ŠTORCH. Its age (432 Myr) is inferred from the associated graptolite fauna, including the zonal index graptolite Monograptus belophorus. Megafossils have clear similarity with Cooksonia, due to their dichotomised axes with slightly widened subtending axes bearing putative sporangia. They document some of the plant diversity that was in place when the first proven representative of the genus Cooksonia appeared, and together with dispersed spores they provide strong and important evidence that a diversified terrestrial ecosystem had developed on the Barrandian volcanic archipelago in the peri-Gondwanan realm by the end of the Sheinwoodian Stage of the Silurian Period.</jats:p>

Dynamics of Silurian Plants as Response to Climate Changes

“…Northwest Gondwana (peri-Gondwana) provides the oldest true vascular land plants, Cooksonia barrandei and Cooksonia sp. ( Figure 5 ), from the Czech Republic (Barrandian area, the Prague Basin) [ 77 , 78 ]. These globally important specimens come from the Monograptus belophorus Biozone of the Sheinwoodian Age.…”

“…These globally important specimens come from the Monograptus belophorus Biozone of the Sheinwoodian Age. Sheinwoodian localities of the Barrandian area yielded several unpublished early land plants of different affinities (rhyniophytes, probably zosterophylls, cryptosporophytes) [ 77 , 78 , 79 , 80 ]. Current research suggests that cooksonioid dominated plant assemblages were accompanied by Ascomycota [ 81 ], Prototaxites sp., and enigmatic Pachytheca [ 82 ].…”

“…The circle at the end of the connecting line between the assemblage/plant unit and stratigraphy levels indicates the accuracy of the stratigraphic determination-the more right this point is, the more accurate the determination. Assemblages : W1 = Barrandian area, the Prague Basin, Czechia [ 77 , 78 , 79 , 80 ]; W2 = Souther Bolivia [ 89 ]; W3 = Gasport Stone Quarry, Niagara County, New York State, USA [ 90 ]; L1 = Welsh Basin (Cwm Craig Ddu, Powys) [ 91 ]; L2 = Welsh Basin (Capel Horeb, Powys) [ 90 ]; L3 = Bathurst Island, Arctic Canada [ 74 ]; L4 = Victoria, Australia, Centennial Beds [ 42 , 92 ]; L5 = Victoria, Australia, Monograptus Beds [ 42 , 92 ]; L6 = Tarija, southern Bolivia [ 93 ]; L7 = Gotland, Sweden [ 94 ]; P1 = Anglo-Welsh Basin (Ludford Corner, Ludlow) [ 95 ]; P2 = Anglo-Welsh Basin (Perton Lane, Hereford) [ 96 , 97 , 98 ]; P3 = Anglo-Welsh Basin (Freshwater East, Pembrokeshire) [ 99 ]; P4 = Anglo-Welsh Basin (Capel Horeb, Powys) [ 91 ]; P5 = New York State, USA [ 90 ]; P6 = Ontario, Canada [ 90 ]; P7 = Holy Cross Mts., Poland [ 100 ]; P8 = Podolia, Ukraine [ 101 ]; P9 = Barrandian area, the Prague Basin, Czechia [ 38 , 43 ]; P10 = Kazakhstan [ 45 ]; P11 = Kazakhstan, Balkhash area [ 102 , 103 ]; P12 = Junggar Basin, Xinjiang, China [ 104 ]; P13 = Northern Vietnam [ 105 ]; Isolated finding of plants : Wa = Barrandian area, the Prague Basin, Czechia [ 83 ]; Wb = Tipperary, Ireland [ 106 ]; La = Northern Greenland [ 75 ]; Lb = Bathurst Isl...…”

“…A high diversity of plant types is indicated by the occurrence of dispersed spore assemblages from localities in the Barrandian area (the Prague Basin). For example, the analysis of a Homerian sample coming from a single bed revealed at least ten to twelve types of trilete spore producing plants and three to four types of cryptosporophytes as early as in the Middle Sheinwoodian [ 78 , 79 ]. This fact evoked an idea that relatively rich terrestrial plant assemblages evolved continuously through the Wenlock, through at least two graptolite biozones, in the volcanic islands of the Barrandian area (the Prague Basin), the Czech Republic.…”

Early Silurian (mid-Sheinwoodian) palynomorphs from the Loděnice-Špičatý vrch, Prague Basin, Czech Republic

“…Land plant remains and dispersed palynomorphs, described herein, have been preserved in a relatively distal facies of laminated brown-grey calcareous and tuf faceous shale with a rich and diversified marine fauna. A number of sterile cooksonioids, newly collected in the test pit above the local road from Loděnice to Bubovice (GPS coordinates 49° 58´ 53.48˝ N, 14° 9´ 25.14˝ E), immediately next to the original Barrande's locality, were briefly discussed by Libertín et al (2018b). The entire section was described by Bouček (1941) and Kříž (1992).…”