Systematics, Phylogenetics, and Reproductive Biology of Flemingites Arcuatus Sp Nov., An Exceptionally Preserved and Partially Reconstructed Carboniferous Arborescent Lycopsid

Exceptionally preserved lycopsid remains from an ex situ chert-carbonate cobble found on the Yorkshire coast, United Kingdom, are here reconstructed as Flemingites arcuatus sp. nov. Megasporophylls are C shaped and emerge from the cone axis at a relatively acute angle. Megasporangia are adaxial on sporophylls and typically contain four megaspore tetrads. Megaspores are described as Lagenicula wellmanii sp. nov.; they are 1.0-1.7 mm in diameter and have a pronounced gula and numerous vermiform spines with bulbous apices. Archegonia occur in some megaspore apices, and developing oocytes are also rarely preserved. Trilete microspores found in an isolated microsporangium conform to Lycospora orbicula. Leaves and sporophylls are helically arranged and have stomata organized in rows along abaxial grooves. Correlation of these organs allowed the resulting partial plant to be added to an existing cladistic matrix. Analyses confirmed the provisional assignment of F. arcuatus to the stem genus Paralycopodites. Stratigraphic comparisons of the megafossils and spores restrict the likely age of the cobble from the Early Mississippian to the Middle Pennsylvanian. The plants were deposited alongside univalve crustaceans in a swamp environment where preservation was probably enhanced by local volcanic activity. The as yet unlocated lagerstatte appears comparable in quality of preservation with the Lower Devonian Rhynie Chert.