CONICET | Buscador de Institutos y Recursos Humanos

Within the central-northern region of Uruguay, the Devonian sequence has been recognized both, in subsurface and outcrops and it constitutes the southern sector of the rift related intracratonic Durazno Group. This unit record the transgressive-regressive cycle within a siliciclastic shallow-marine platform and it is characterized by malvinokaffric affinity invertebrates that suggest a Lower Devonian age. Outcrops of Devonian rocks can be found in several localities of the Durazno Department, Uruguay and they comprises from base to top the Cerrezuelo, Cordobés and La Paloma formations. Hostinella was reported from the Cerrezuelo Formation. Acritarchs, pollen and spores were reported from the Cordobés formation, and the fossil plants here presented. Fossil plants were found in the type locality (Cordobés river) and in the Blanquillo quarry, composed of white-greyish kaolinitic shales. They comprise fragmentary compressions of a lateral bi to tripinnate, helically arranged branching system. Main axes are rigid, striated and sometimes bifurcated. Second order axes are rigid and record the last order appendages. These lateral appendages are thin and show a central vascular trace. In the proximal region, the lateral appendages are rigid and loosely arranged, while in the distal region are flexuous and dense. Taking into account the morphological attributes observed this material is comparable with lateral appendages similar to Aneurophyton Kräusel & Weyland, ancestral to Gymnosperms. These forms are characteristic from the Devonian of Euroamerica, and here we present the first reference of this taxon to the southwest of Gondwana.