Petrified Marattiales pinnae from the Lower Permian of North-Western Gondwana (Parnaiba Basin, Brazil)

Abstract

This study concerns silicified fertile pecopterid pinnae from the Permian of the Parnaiba Basin, State of Tocantins, northern Brazil, attributed to a new fern taxon of Marattiales, Buritiranopteris costata gen. nov. et sp. nov. This fern bears groups of three or four sporangia radially arranged in closely spaced synangia, as in some species of Scolecopteris and Acitheca, but they are completely enclosed in thick and long down-curved foliar lobes. This morphology may represent a xeromorphic adaptation against long seasonal drought and direct solar irradiation. These pinnae obviously belonged to one of the abundant marattialean tree ferns, most probably Tietea, which were apparently successful as riparian vegetation of ephemeral rivers. (C) 2013 Elsevier B.V. All rights reserved.