A new species of Tetraxylopteris (Aneurophytales) from the Devonian of Venezuela

Recent investigations of the Middle and Upper Devonian Campo Chico Formation, north-west Venezuela, led to the discovery of a new aneurophytalean progymnosperm, Tetraxylopteris reposana sp. nov. The fossils allow the most detailed morphological outline of a species of Tetraxylopteris Beck to date, and indicate there was more variation within the genus than yet recognized. Tetraxylopteris reposana was probably a bushy plant which formed dense interlocking thickets. Its morphology highlights the similarity between Tetraxylopteris and Proteokalon Scheekler & Banks, and the potential synonymy of these taxa is discussed. Furthermore, there is a morphological continuum between the fertile organs of Tetraxylopteris and Rellimia Leclereq & Bonamo. As the first definitive documentation of Tetraxylopteris in Gondwana, this study indicates aneurophytalean progymnosperms were more widespread than formerly understood. The diversity of the Campo Chico Formation floras and similarity of their composition to northern palaeocontinent assemblages (e.g. the Catskills Clastic Wedge) support the concept of a largely uniform worldwide vegetation. (c) 2005 The Linnean Society of London.