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Dordrechtites Arcanus Sp. Nov., An Anatomically Preserved Gymnospermous Reproductive Structure From the Middle Triassic of Antarctica
Bergene, Julie Anne ; Taylor, Edith L. ; Taylor, Thomas N.
Bergene, Julie Anne
Taylor, Edith L.
Taylor, Thomas N.
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Abstract
The genus Dordrechtites is an isolated ovulate structure previously described only from South Africa and
Australia as impressions. The discovery of compressed and permineralized specimens of this taxon at the base
of Mount Falla (uppermost Fremouw Formation) in the central Transantarctic Mountains extends the
geographical and geological distribution of the genus and increases the known floral diversity of the Triassic of
Antarctica. The first permineralized species, Dordrechtites arcanus, is described using standard acetate peel
techniques and includes internal anatomy of an elongate arm that extends over the top of a central cupule
containing two elongate, bilaterally symmetrical, orthotropous ovules. An arc-shaped collateral vascular
bundle extends from the arm into the top of the cupule, branches, and then extends around the ovule to about
halfway down to the micropylar end. The cupule is parenchymatous and includes transfusion tissue with cells
that have pitted walls. The sclerotesta of the ovule is up to 200 mm thick, consisting of an outer layer with
longitudinally oriented, thick-walled cells and an inner layer one cell thick of rectangular, thick-walled cells.
The micropyle is flared at the attenuated tip of the pyramidal cupule. The four previously described species of
Dordrechtites have uncertain affinities, and although the morphology and anatomy of this taxon is now
known, the affinities within the gymnosperms are still uncertain.
Description
This is the publisher's version of an article which is being shared with permission. The original version may be accessed at: http://dx.doi.org/10.1086/668792
Date
2013
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University of Chicago Press
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Keywords
Triassic, Gymnosperm, Cupule, Ovules, Central transantarctic mountains
Citation
Bergene, J.A., Taylor, E.L., and Taylor, T.N. 2013. Dordrechtites
Arcanus Sp. Nov., An Anatomically Preserved Gymnospermous
Reproductive Structure From the Middle Triassic of Antarctica.
International Journal of Plant Science 174(2): 250-265.