The first evidence of the fern Botryopteris from the Permian of the Southern Hemisphere reflecting growth form diversity

Abstract

New specimens of Botryopteris Renault deriving from the Permian of the Maranhão Basin (NE Brazil) are both the first evidence of this palaeozoic fern group from the Southern Hemisphere and the youngest known to date. These remains cannot be assigned to any known species of the Botryopteridaceae. Therefore, the new species Botryopteris nollii sp. nov. is established. One of the most conspicuous characters of this new fern is the ability to grow in different forms. Firstly, it has been found rooted within the marginal trunk base of the tree ferns Grammatopteris freitasii Rößler and Galtier and Psaronius brasiliensis Brongniart. Secondly, cauline organs, foliar members and adventitious roots of this fern formed a compound system of a so-called false trunk. This results from the formation of closely spaced spirally arranged foliar members of different order on upright stems and of the repetitive development of shoots from foliar-borne buds inside the trunk. The newly collected material is preserved as silicified permineralisation, and therefore allows to recognise characters of vegetative morphology but also details of the anatomy and internal organisation. Botryopteris nollii sp. nov. is characterised by nearly circular protostelic stems and stipes/rachises that show a dorsiventral ω-shaped vasculature. The new fern underlines the striking growth form diversity seen in the whole family Botryopteridaceae.