A STRUCTURAL REINTERPRETATION OF THE ENIGMATIC CARBONIFEROUS MIOSPORE PTERORETIS FELIX & BURBRIDGE 1961 EMEND. NOV

Abstract The structure of the enigmatic Carboniferous miospore genus Pteroretis Felix & Burbridge 1961 is reinterpreted based on well-preserved assemblages from Pennsylvanian (Duckmantian–Bolsovian) strata in the Machrihanish Coalfield, Kintyre, western Scotland. The genus is emended herein, and evidence is presented of a proximal operculum to justify assignment of the genus to the Infraturma Epitygmati. The complex arrangement of wings, originally described as being perpendicular to the equatorial margin from pole to pole, are demonstrated to be concentric structures in the equatorial and subequatorial regions. Wings developed on the distal surface commonly form a cuppa structure similar to that developed in Fragilipollenites Konyali 1965 emend. McLean 1997. A comparison is made with Vestispora (Wilson & Hoffmeister 1956) Wilson & Venkatachala 1963, the only other operculate Carboniferous miospore genus. Comparisons are also made with other genera such as Columinisporites Peppers 1964 and Fragilipollenites, which are costate and cuppa-bearing respectively. Previous records of Pteroretis from Europe and North America are reviewed, and indicate a Late Mississippian (Late Viséan–Chesterian) to Mid Pennsylvanian (Bolsovian) age. Paleobotanical evidence suggests a sphenophyllalean origin, with Pteroretis miospores being recovered from the fructifications of several species of Bowmanites Binney 1871.

[1]  M. Oliwkiewicz-Miklasińska.  New distinctive miospore species from the Namurian of the Upper Silesia Coal Basin, Poland , 2001, Journal of Micropalaeontology.

[2]  D. McLean.  The miospore genus Fragilipollenites Konyali emend, from the Silesian of Great Britain , 1997, Journal of Micropalaeontology.

[3]  S. Davies,et al.  Spectral gamma-ray and palynological characterization of Kinderscoutian marine bands in the Namurian of the Pennine Basin , 1996 .

[4]  D. McLean.  Provenance of reworked palynomorphs from the Greenmoor Rock (Langsettian, Late Carboniferous) near Sheffield, England , 1995 .

[5]  N. Turner,et al.  Palynological evidence for the early Namurian age of the “Millstone Grit” and Upper Limestone Group around Longhoughton Steel, Northumberland , 1992 .

[6]  R. Neville.  Three new miospore genera from the Lower Carboniferous (Viséan) rocks of east Fife, Scotland , 1989, Journal of Micropalaeontology.

[7]  W. Taylor.  Ultrastructure of sphenophyllalean spores , 1986 .

[8]  F. Ettensohn,et al.  Palynology and biostratigraphy of Pennington shales and coals (Chesterian) at selected sites in northeastern Kentucky , 1979 .

[9]  C. Foster.  Permian plant microfossils of the Blair Athol coal measures, Baralaba coal measures, and basal Rewan formation of Queensland , 1978 .

[10]  D. Mishell,et al.  PALYNOLOGICAL DIVISION OF THE NAMURIAN OF NORTHERN ENGLAND AND SCOTLAND , 1977 .

[11]  C. H. Holland,et al.  A correlation of Silurian rocks in the British Isles , 1971, Journal of the Geological Society.

[12]  T. Taylor.  The morphology of Bowmanites dawsoni spores , 1970 .

[13]  C. Felix,et al.  Additional knowledge of Pteroretis , 1969 .

[14]  A. H. Smith,et al.  Miospores in the coal seams of the Carboniferous of Great Britain , 1967 .

[15]  C. Felix,et al.  Pteroretis, a new Mississippian spore genus , 1961 .

[16]  W. Hoffmeister,et al.  Mississippian plant spores from the Hardinsburg Formation of Illinois and Kentucky , 1955 .

[17]  A. T. Cross,et al.  Monograph of the Paleozoic Cone Genus Bowmanites (Sphenophyllales) , 1943 .

[18]  B. Knox.  The Spores of Pteridophyta, with Observations on Microspores in Coals of Carboniferous Age , 1938 .

[19]  S. Leclercq.  Introduction à l’étude anatomique des végétaux houillers de Belgique : les coal balls de la couche Bouxharmont des charbonnages de Wérister , 1925 .

[20]  D. Thoday.  I.—ON A SUGGESTION OF HETEROSPORY IN SPHENOPHYLLUM DAWSONI. , 1906 .

[21]  W. Williamson,et al.  Further Observations on the Organization of the Fossil Plants of the Coal-Measures. Part I. Calamites, Calamostachys, and Sphenophyllum , 1894 .