Two new species of Sonapteris gen. nov. (Botryopteridaceae) based on compressions from the Upper Carboniferous (Bolsovian-Westphalian D) of the Pilsen Basin, Bohemian Massif

Sonapteris gen. nov. is established for two new species S. barthelii sp. nov. and S. pilsensis sp. nov. from the Bolsovian and Westphalian D of the Pilsen Basin, Czech Republic. Sonapteris barthelii sp. nov. and S. pilsensis sp. nov. were studied palynologically and morphologically. Both species are based on fertile specimens, which show branching systems bearing fertile organs, annulate sporangia and spores of a botryopterid type. Sonapteris gen. nov. is assigned to the family Botryopteridaceae. Whereas S. barthelii shows great similarities to the lower Carboniferous species B. antiqua, S. pilsensis does not show superficial similarities to any botryopterid species in general view. The anatomy of both new species remains unknown, and so it is impossible to place them in the genus Botryopteris Renault. In situ spores isolated from S. barthelii belong to the dispersed genus Leiotriletes-Granulatisporites-type. Different stages of maturity were observed in the spores isolated from S. pilsensis. The first type consists of laevigate spores closely comparable to several species of the dispersed genus Calamospora (relatively immature forms); the second, intermediate type consists of scabrate, microgranulate to microverrucate spores that can be correlated with the dispersed genera Verrucosisporites, Apiculatisporis or Planisporites; and the third (fully matured) type consists of clavate, baculate to spinate spores that belong to the dispersed genus Raistrickia. Such ontogenetic stages of botryopterid spores are described for the first time and they resemble similar maturity stages of spores of Senftenbergia plumosa. Sonapteris barthelii may represent a liana-like or epiphytic kind of fern, that grew on Psaronius trunks with Pecopteris tuffitica-type fronds. However, the general habit of S. barthelii remains unknown.