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Abstract Detail


Paleobotanical Section

Hermsen, E. J. [1], Taylor, Thomas N. [2], Taylor, Edith L. [2].

An unusual structure (ovule?) from the Middle Triassic of Antarctica.

Permineralized peat from the Middle Triassic Fremouw Formation, Central Transantarctic Mountains, Antarctica, is an important asset to understanding Triassic floras, being one of the few permineralized floras representing this time period in the world. To date, a variety of fungi, equisetophytes, ferns, and seed plants have been described from the peat. Here, we describe an unusual ovule-like structure found in a matrix type that also yields Endochaetophora (Fungi, Ascomycota?) and Notophytum (Coniferales, Podocarpaceae). This structure is represented by four specimens ca. 2.1-6.1 mm in length x 1.7-2.9 mm in width. The structure is elliptical, rounded at one end and tapering at the other. It consists of a central tissue mass ca. 1.7-3.4 mm long x 1.2-1.3 mm wide surrounded by two layers of tissue, with a third, very thick, and poorly preserved outer layer. The most distinctive feature of the central tissue mass is the presence of fingerlike peripheral groups of cells projecting inward toward the center of the structure, each group surrounded by a thickened wall distinguishing it from the surrounding undifferentiated tissue. These peripheral projections are ca. 80-250 μm in width and extend ca. 300-430 μm from the periphery of the structure to the center. Interior to these projecting groups of cells are small clusters of tracheids. The outer boundary of the central mass is delimited by a single layer of small, square cells. The two innermost tissue layers surrounding the central mass are similar, made up of parenchymatous cells and bound toward the outside with small, square cells. The innermost layer is ca. 150 μm thick, the outer varying from ca. 100-250 μm thick. The outermost layer of tissue is thick and poorly preserved, with large clusters of tracheids. The possible identity of this structure will be discussed.


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1 - University of Kansas, Ecology and Evolutionary Biology, Haworth Hall, 1200 Sunnyside Avenue, Lawrence, Kansas, 66045-7534, USA
2 - University of Kansas, Department of Ecology & Evolutionary Biology, Natural History Museum and Biodiversity Research Center, 1200 Sunnyside Avenue, Lawrence, Kansas, 66045-7534, USA

Keywords:
Fremouw Formation
Triassic
Antarctica
permineralization.

Presentation Type: Oral Paper:Papers for Sections
Session: CP27
Location: Lake Erie/Hilton
Date: Tuesday, July 10th, 2007
Time: 8:30 AM
Number: CP27002
Abstract ID:1856


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