Acta Palaeontologica Polonica

Megaspores of the turma zonales from the Carboniferous of Poland. Part I - coronate megaspores

Jadwiga Karczewska

Acta Palaeontologica Polonica 20 (4), 1975: 447-500

Eight Carboniferous coronate megaspores species, assigned to the genera Radiatisporites, Rotatisporites, and Zonalesporites, structure of the spore wall and mesospore ornamented by numerous cushions are described. Corona has equatorial appendages connected by a membrane and displays two centrifugal channels. Structure of the spore wall, corona and that of laesurae were studied in SEM and in transmitted light. The structure of the corona is of basic taxonomic value for determining genera and species. The main evolutionary trends are changes of the corona; the main types appear in the Upper Visean and develop at a different evolution rate along four lines: 1. Rotatisporites solidus - Radiatisporites radiatus; 2. Rotatisporites tulensis - R. rotatus - R. dentatus; 3. Zonalesporites mucronatus - Z. superbus; 4. Z. brasserti. A peculiar state of preservation of Z. brasserti f. circum-textus is described and explained.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (for details please see, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.