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Abstract Detail



Paleobotanical Section

Ryberg, Patricia [1], Gordon, Ashleigh [1].

Glossopterid reproductive diversity from the Allan Hills, Antarctica.

Investigations of the Allan Hills locality in the Weller Coal Measures of Victoria Land, Antarctica (76° 42.5’ S; 159° 41.6’ E) have been conducted for several decades and the only glossopterid megasporophyll genus known was the multiovulate Plumsteadia. However, during a recent excursion to this locality during the 2011–2012 Antarctic field season, numerous genera of both ovulate and pollen sporophylls were discovered, most of which are hitherto unknown to either the Allan Hills locality or all of Antarctica. One exposure was dominated by the either the genus Rigbya or the genus Nogoa, both of which are megasporophylls characterized by terminal lamina or cupule-like structures. The difference between these two genera is the number of ovules attached to each terminal structure. A new multiovulate megasporophyll species has also been found in the Allan Hills. These new specimens resemble the genus Ottokaria, a genus that was widespread across Gondwana, but had no confirmed presence in Antarctica until now.
Additionally pollen genera are found in abundance from the same outcrop. The most common impression genus, Eretmonia has a significant presence in the flora with the distinctive scale leaf with two clusters of microsporangia at the region where the petiole expands into the blade. The microsporophyll genus Squamella is also present in these deposits. This is the first record of the genus in Antarctica. Its most distinctive trait from Eretmonia is the absence of a petiole in the scale leaf. The abundance of scale leaves with a distinctive petiole and those without a petiole indicates that a taphonomic changes did not occur in which petioles of Eretmonia were lost to produce the Squamella morphology.
The inclusion of these genera to the Allan Hills locality suggests that there may have been greater diversity of the glossopterids in Antarctica in the early Late Permian than the Late Permian. Another possibility is that the difference between sedimentary basins is due to more localized migrations of glossopterid genera from surrounding Gondwanan continents.


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1 - Park University, 8700 NW River Park Dr, Parkville, MO, 64152

Keywords:
Permian
Antarctica
Glossopterids.

Presentation Type: Oral Paper:Papers for Sections
Session: 24
Location: Salon 5/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 4:15 PM
Number: 24003
Abstract ID:840
Candidate for Awards:None


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