Ryberg, Patricia E. , Taylor, Edith L. .
Glossopterid reproductive structures from the central Transantarctic Mountains, Antarctica.
While there is a solid record of glossopterid reproductive structures in South Africa, India, and Australia, a large gap is present in our knowledge of Antarctic specimens. Descriptions of four new species of reproductive structures from impression material from the central Transantarctic Mountains will increase the knowledge of the diversity of glossopterid reproductive structures both in Antarctica and the Southern Hemisphere. A Plumsteadia-like structure has an extremely acute apex and a broad, blunt base. No specimens have been found attached to vegetative leaves. Ovules are radially aligned from the center of the base of the sporophyll to the apex, and the margin of the sporophyll contains a row of elongated ovules. Specimens without ovules reveal pits where ovules were attached, with a raised portion in the center of the pit believed to be the vascular supply to the ovule. A Rigbya-like structure contains at least four receptacles, each containing a single ovule. Each receptacle is terminal on a small stalk, and all stalks arise from the same point on the pedicel. Pedicels were long but have not yet been found attached to another structure. An Eretmonia-like specimen represents a microsporangiate structure consisting of a scale-like leaf with two branching stalks at the basal portion of the sporophyll. Further divisions of the stalks occur distally with terminal clusters of pollen sacs. The pollen sacs found in Eretmonia are similar to those found in the specimens with Arberia-like organization. Arberia is the genus assigned to isolated clusters of pollen sacs in the matrix associated with no organ. Individual sacs are striate with a narrow blunt proximal end and a bulbous distal end. With these new reproductive structures, the true diversity of the glossopterids in Antarctica is beginning to come to light.
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1 - University of Kansas, Department of Ecology & Evolutionary Biology, Natural History Museum and Biodiversity Research Center, 1200 Sunnyside Avenue, Lawrence, Kansas, 66045-7534, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 28th, 2008
Time: 9:00 AM