Abstract Detail

Paleobotanical Section

Ryberg, Patricia [1], Taylor, Edith [2], Taylor, Thomas [3].

Mt. Achernar: A window into Antarctic glossopterid diversity.

Impressions of glossopterid reproductive organs are known in Antarctica from the Horlick Mountains to southern Victoria Land. To date, two impression ovulate genera have been described and they do not have overlapping ranges of distribution. This study provides the first evidence of a locally diverse flora at Mt. Achernar in the Central Transantarctic Mountains. Three genera of glossopterid ovulate structures, including the multiovulate Plumsteadia and Scutum as well as a new morphotaxon, were found approximately 18 meters below the level from which a permineralized forest was previously described within the upper part of the Upper Permian Buckley Formation. The new morphotaxon consists of cupules helically attached to a stem. A single vein enters the base of a cupule and then diverges five to six times with secondary veins extending to the margin of the lobed cupule. Cupules measure 4.0–6.6 mm in length and 4.8–8.0 mm wide. Up to five biwinged ovules, each measuring 3.0–3.7 mm by 2.9–3.7 mm, are attached in each cupule. Two morphogenera of ovulate structures in the glossopterid clade are currently identified as bearing cupules, which either extend from the midrib of a leaf or are attached at the end of an isolated stalk. Unlike these previously described morphogenera, however, the new taxon from Mt. Achernar bears cupules attached to an axis in a helix. In addition to this new taxon, the presence of Scutum represents the first record of the genus in Antarctica. Plumsteadia has been documented at Mt. Achernar but collections from the 2010–2011 Antarctic field season reveal specimens at a higher density than previously recorded, perhaps indicating that numerous ovulate structures were produced in some organized structure not yet observed. Previous studies on Antarctic glossopterids have provided only a hint to the glossopterid diversity of Antarctica, and the Mt. Achernar locality provides a localized snapshot of the heterogeneity of the glossopterids in Antarctica.

Broader Impacts:

1 - University Of Kansas, Department Of Ecology & Evolutionary Biology, 1200 Sunnyside Ave., Lawrence, KS, 66045, USA
2 - University Of Kansas, Department Of Ecology And Evolutionary Biology, 1200 Sunnyside Avenue, Haworth Hall, Lawrence, KS, 66045-7600, USA
3 - University Of Kansas, Department Of Ecology And Evolutionary Biology, 1200 Sunnyside Avenue, Haworth Hall, Lawrence, KS, 66045-2106, USA

Keywords:
Antarctica
Late Permian
Glossopteris
Plumsteadia
Scutum
new morphotaxon
ovulate structures.

Presentation Type: Oral Paper:Papers for Sections
Session: 21
Location: Lindell C/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 4:00 PM
Number: 21002
Abstract ID:51