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Brian L. Youngs

Project Topic / Abstract:

“Pollen Morphology and Ultrastructure of Pramelreuthia, a 230 Million-Year Old Fossil Gymnosperm”

Pramelreuthia is an extinct gymnosperm with a fossil record placing it in the Upper Triassic (210-230 million years ago). To date, the plant has only been known from compressed pollen-producing organs from Austria; however two new species have recently been discovered in Utah. In the present investigation, in situ pollen grains from P. duvielii and P. yazzi have been isolated and critically studied using light, scanning electron, and transmission electron microscopy. Pollen grains have been analyzed both in clusters and individually. The grains are relatively small, averaging 53 ┬Ám in legnth, bisaccate, and have a single, elongate aperture. The characters examined include sizes (overall, main body, sacci), wall thicknesses and infrastucture (proximal, distal, aperture, and sacci), and internal structure of the sacci. Historically, Pramelreuthia has been taxonomically linked to both cycads and seed ferns, but there is no concensus about its true affinities. It is hoped that this research will aid in resolving the natural classification of this fossil.

Presentations:

1999

  • Truman Undergraduate Research Symposium (Kirksville, MO)
  • Sigma Xi Student Research Symposium (Kirksville, MO)