First attached cones from Sphenophyllum speciosum (Royle) McClelland 1850 from the Permian La Golondrina Formation (Santa Cruz, Argentina)

CARIGLINO, BÁRBARA; PREVEC, ROSE

Simposio; XVII Simposio Argentino de Paleobotánica y Palinología; 2018

With a fossil record spanning from the Devonian to the Triassic, the Order Sphenophyllales (Class Sphenopsida) was a common understory component in forests of both the Northern and Southern hemispheres. In Permian Gondwanan floras, these sphenopsids were frequently found alongside glossopterids, cordaitaleans, lycophytes and ferns. Sphenophyllum, its most representaVve genus, is known mainly by vegetative organs (i.e., leaves and stems), all quite morphologically similar among the different species. In contrast, the reproductive structures of these plants show an interesting amount of physiognomic variation. Here, we present the first examples of foliar shoots of Sphenophyllum speciosum (Royle) McClelland with reproductive structures attached. The cones, preserved as adpression fossils, are described in detail and compared to other impression/compression sphenophyllalean strobili. Apart from being the first Sphenophyllum speciosum found with attached cones, these findings are of main interest because they will assist in determining whether these Gondwanan forms, that show consistent anisophylly and which have been in some cases referred to Trizygia speciosa Royle emend. Pant and Mehra, are sufficiently divergent fromthose of the northern hemisphere forms to be placed within a separate genus.