ANTARCTICA: ENHANCING THE LINKS ACROSS TIME AND SPACE OF THE PERMIAN GLOSSOPTERIDS

Abstract

The Permian was a period of transition in Antarctica as the glaciers of the Carboniferous and Early Permian retreated (Isbell, 2010), and the landscape became dominated by the plants of the Glossopteridales. The geographic range of the glossopterids extended across all of subequatorial Gondwana (McLoughlin, 2011). The group is identified with tongue-shaped leaves (genus Glossopteris ) and is most often reconstructed as arborescent with Agathoxylon -type uniseriate coniferous wood. A distinctive rooting structure with conspicuous air spaces, Vertebraria , is found in association with the wood and leaf genera. These three genera are fairly conservative in their morphology across all of Gondwana. Glossopteris has hundreds of defined species, but the criteria used to delimit species relies heavily on secondary vein architecture and studies on extant plants have shown that there is a wide range of vein architecture found within a single plant (e.g., Boyce, 2009), suggesting that perhaps vein architectural features do not provide valid information on the diversity found within Glossopteris . The diversity of the group is known from reproductive structures, and most often from ovulate structures (e.g., Ryberg, 2009; Prevec, 2011; McLoughlin, 2012; Ryberg et al., 2012a). More than 20 genera of ovulate organs are associated with the glossopterids from across Gondwana. In Antarctica at least five genera are known and they span three distinctive morphologies. The most common morphology, which is found on …