Temme, Thomas , Sandau, Stephen .
First Occurrence of the Fern Thelytperis in the Uinta Basin, Utah, USA: Possible New Species.
Fossil material of the fern genus Thelypteris was discovered during a paleontological monitor of an oil field construction site in Duchesne County, Utah. A total of 43 specimens containing compressions and impressions of partial and fragmented pinnae were collected from the Green River Formation of the Uinta Basin, preserved in gray, sub-lithic siltstone. The stratigraphy of the area is suggestive of a lagoon or backwater depositional environment. Identifiable foliage consists of well preserved fragments, four to nine centimeters long, which appear to be bi-pinnate and pinnatifid with ovate pinnule tapering to an acute to rounded tip. Of the 43 specimens collected, 61% have pinnules that are united for approximately half of their length, with 12-14 simple, slightly curving veins; 22% have pinnules that are united for approximately half of their length, with 6-8 simple, slightly curving veins; 5% have pinnules that are united for approximately one-third of their length, with 10-12 simple, slightly curving veins; and 16% could not be differentiated. All of the foliage appears to be sterile. The specimens collected compare well with T. iddingsi and T. weedii from the Eocene Yellowstone-Absaroka volcanic province of Wyoming. However, differences in morphology (apex, depth of dissection and the vein counts of the pinnules) and geographical distance may suggest new species of Thelypteris.
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1 - Intermountain Paleo-Consulting, 461 w 200 s, Vernal, Utah, 84078, United States
Green River Formation
Presentation Type: Poster:Posters for BSA Sections
Location: Event Tent/Cliff Lodge
Date: Tuesday, July 28th, 2009
Time: 5:30 PM