An Early Devonian flora, including Cooksonia, from the Parana Basin (Brazil)

We report here the presence of an extensive flora from an early Lochkovian (Lower Devonian: similar to 406 million years) locality in the Parana Basin (Brazil). The exceptional macrofossil assemblage includes several hundred specimens of a new Cooksonia species, and representatives of 10 other taxa, 5 of which at least are new. This plant assemblage illustrates the amplitude of the Siluro-Devonian land plant primary radiation. During the Lochkovian, the Parana Basin was positioned in southern Gondwana, within the southern polar circle. The occurrence of this rich plant assemblage substantiates the hypotheses of a Warm Mode and of an ice-free southern pole during the earliest Devonian. Some taxa exhibit characters interpreted as potentially related to cold hardiness: embedding of the sporangium within the axis, abundance of emergences, dense branching, and protection of the apical meristem. (C) 2001 Elsevier Science B.V. All rights reserved.