Original paper

The generic taxonomy of Pennsylvanian age marattialean fern frond adpressions

Cleal, Christopher J.

Abstract

Traditionally, most adpressions of Pennsylvanian marattialean fronds from Euramerica belong to a family for which the correct name is Psaroniaceae. Most were assigned to just one fossil-genus (Pecopteris) but in recent years there has been increasing awareness that these fronds are far more heterogeneous and should be split into different fossil-genera based on a combination of venation, pinnule morphology, soral morphology and spores. Seven such genera can be recognised: Asterotheca, Lobatopteris sensu stricto, Lobatopteris auct., Cyathocarpus, Acitheca, Diplazites and Remia, plus an eighth genus (Polymorphopteris) for certain species with a distinctive venation but for which reproductive structures are unknown. Pecopteris in this context should be restricted to the tedeleacean species formerly included in Senftenbergia and not used for marattialean fronds. Some of these genera can be recognised in the Pennsylvanian and Cisuralian floras of China, but other genera are also present here. The taxonomic position of the psaroniacean fronds from Gondwana remains uncertain. Although some of these adpression genera (e.g. Acitheca) can be equated with fossil-genera based on anatomically preserved fossils, in general it is best if the two sets of genera based on the different preservation states are kept separate.

Keywords

PalaeobotanyPennsylvanianMarattialesFrondsTaxonomy