Abstract Detail

Paleobotany

Ryberg, Patricia E. [1], Serbet, Rudolph [2], Atkinson, Brian [3], Isbell, John [4], Ives, Elizabeth [5], Taylor, Edith L. [6].

A latest Permian high-latitude Glossopteris flora.

Localities in Antarctica have provided abundant data on both the Late Permian (260–252 Ma) Glossopteris flora as well as the Middle Triassic (247–237 Ma) Dicroidium flora from compression/impression as well as permineralized fossils. Yet, no record of a floral transition from the Late Permian glossopterids to the Middle Triassic corystosperm floras has been documented in central Antarctica. Published stratigraphic reports on Collinson Ridge in the Shackleton Glacier region have proposed a Lower Triassic correlation based on lithology as demonstrated by deposits indicative of a braided river system that was mainly dominated by coarse grained sandstones. Conversely, a paleobotanical study from material collected from a single exposed lens (McManus et al., 2002) indicated that while Collinson Ridge has lithology characteristic of the Lower Triassic Fremouw Formation, the rocks contain a Late Permian flora based on the presence of Glossopteris and the absence of the vertebrate Lystrosaurus. On a recent field expedition to the Collinson Ridge locality (2017-2018), an extensive collection of permineralized peat from several exposed lenses and debris slopes was gathered. The peat is dominated by various glossopterids including: leaf mats, long and short shoots, Vertebraria, and at least three morphologically distinctive ovules, as well as unclassified microsporangiate structures containing numerous pollen sacs have been identified. The abundance of the glossopterids and dearth of other plant groups is a typical characteristic of a low diversity landscape common during the Late Permian of Antarctica. However, initial observations from this new collection of material hint that the plant remains at Collinson Ridge display anatomical features distinctive from other comparable permineralized floras and illustrate that the diversity of glossopterids across Antarctica may be greater than currently known. Additionally, the lithology depicts a depositional environment in which the river system had evolved to infill the classic high water table of Permian meandering rivers and formed the Triassic braided rivers. This would suggest that Collinson Ridge is one of the few Gondwanan localities where latest Permian fossils may provide details on the diversity, biology, and ecology of the plants that inhabited Antarctic floras shortly before the Permian–Triassic extinction.

1 - Park University, 8700 NW River Park Dr, Parkville, MO, 64152, USA
2 - University Of Kansas, Division Of Paleobotany, Biodiversity Institute, 1200 Sunnyside Avenue, Lawrence, KS, 66045, United States
3 - University of Kansas, Department of Ecology and Evolutionary Biology, 2041 Haworth Hall 1200 Sunnyside Avenue , 1200 Sunnyside Avenue , Lawrence, KS, 66045, US
4 - University of Wisconsin Milwaukee, Geosciences, Milwaukee, WI, 53206, USA
5 - University of Wisconsin- Milwaukee, Geosciences, Milwaukee, WI, 53206, USA
6 - University of Kansas, Ecology and Evolutionary Biology and Biodiversity Institute, 1200 Sunnyside Drive, Haworth Hall, Lawrence, Kansas, 66045, United States

Keywords:
Glossopteris
Antarctica
Late Permian.

Presentation Type: Oral Paper
Session: 23, Paleozoic and Early Mesozoic Paleobotany
Location: 109/Mayo Civic Center
Date: Tuesday, July 24th, 2018
Time: 8:45 AM
Number: 23002
Abstract ID:663
Candidate for Awards:None