The Westphalian–Stephanian macrofloral record from the South Wales Coalfield, UK

Abstract

The South Wales Coalfield has the most complete Westphalian macrofloral record anywhere on the Variscan Foreland or adjacent basins, with 135 biodiversity-meaningful morphospecies having been recognized. All of the standard macrofloral biozones of the Westphalian Stage have been recognized, although a detailed comparison with the Central Pennines Coalfields has indicated some discrepancies in the relative positions of the biozonal boundaries. Total Species Richness progressively increases through the Langsettian Substage, and then remains relatively stable through most of the Duckmantian and Bolsovian substages. There is a distinct reduction in Total Species Richness towards the top of the Bolsovian Substage, but this partially recovers in the middle Asturian Substage with the appearance of a range of marattialean ferns, and medullosalean and callistophytaleans pteridosperms. There is no evidence of any significant drop in Total Species Richness towards the top of the succession, indicating that conditions at this time were relatively stable. The change from coastal floodplain to alluvial braidplain conditions in middle Bolsovian times correlates with a marked increase in the proportion of medullosalean remains being preserved in the adpression record, reflecting an expansion of the clastic-substrate habitats.

The Okmulgee, Oklahoma fossil flora, a Mazon Creek equivalent: Spatial conservatism in the composition of Middle Pennsylvanian wetland vegetation over 1100km

“…Based on its patterns of occurrence and morphological variation, as established in other studies (see discussion in Wittry, 2006), O. aequalis appears to be a specifically distinct entity based. Cleal (1997Cleal ( , 2007 considered Odontopteris aequalis to be possibly conspecific with Odontopteris cantabrica Wagner differing simply in size, though the fragmentary nature of the type of O. aequalis and its lack of cuticle may be barriers to establishing synonymy . If O. aequalis and O. cantabrica were the same, Cleal (1997) suggests this would be further evidence for assigning the Francis Creek Shale to the O. cantabrica biozone of Wagner (1984), thus making this deposit Cantabrian in age, using terrestrial European stage boundaries.…”

“…In contrast to many such floras described from Europe (e.g., Wagner, 1962Wagner, , 1971Thomas and Cleal, 2001;Cleal, 2004Cleal, , 2005Cleal, , 2007Cleal et al, 2004;Šimůnek, 2008;Libertín et al, 2009;Opluštil et al, 2009;Bashforth et al, 2010;Wagner and Álvarez-Vázquez, 2010), there are relatively few from the United States (Langford, 1958;Basson, 1968;Boneham, 1974;Gastaldo, 1977;Pheifer, 1979;Oleksyshyn, 1982;Wittry, 2006). The current study thus is a baseline that helps establish the composition and structure of coastal wetlands prior to the major changes in vegetation that took place at the Middle-Late Pennsylvanian boundary.…”

Cuticles of Paripteris Gothan, 1941 (Pteridospermopsida) from the Westphalian of Poland

“…In recent literature, the binomial classification of Paripteris is still commonly used, e.g., Migier in Brzyski et Cleal (2008). Therefore, I also use this classification here.…”

“…Not all palaeobotanists accepted this classification, e.g. Cleal & Shute (1995), Migier in Brzyski et al (2001) and Cleal (2008) and others. Laveine et al's (1993) classification fits better to Asian than to European representatives of Paripteris.…”

No Major Stratigraphic Gap Exists Near the Middle-Upper Pennsylvanian (Desmoinesian-Missourian) Boundary in North America

“…Wagner (2003) later proposed that the gap was also present in the Illinois and Midcontinent basins, based on the abrupt transition between Desmoinesian and Missourian floras, which was reported and analyzed in numerous publications (Phillips et al, 1974(Phillips et al, , 1985Pfefferkorn and Thomson, 1982;Kosanke and Cecil, 1996;DiMichele and Phillips, 1996;Peppers, 1996;Blake et al, 2002;Pfefferkorn et al, 2008;. Thus, the far-reaching hypothesis put forward was that a major stratigraphic gap occurred at the Desmoinesian-Missourian boundary over most of eastern and central North America, as is the case across much of northwest Europe (Cleal, 2007).…”