Axsmith, Brian , Skog, Judith E. .
A Triassic Mystery Solved - Fertile Pekinopteris auriculata.
Originally described as a new plant from the Upper Triassic Pekin Formation of North Carolina, Pekinopteris auriculata was based solely on frond fragments. It was suggested to be a fern due to the thin lamina and occasional circinnate fronds, but no fertile material was known. Later research by Delevoryas and Hope uncovered many more specimens, including intact fronds attached to branched, creeping rhizomes. This growth habit strongly supported fern affinities, but fertile material was still missing. This was difficult to explain, as all other fern taxa from the Pekin Formation are now known from abundant fertile specimens despite being less common than Pekinopteris. Recent re-examination of Pekinopteris specimens has revealed the presence of mostly isolated, elongate pinnae occurring among typical fronds. These pinnae have toothed margins and are covered on their abaxial surfaces by large sporangia with apical annuli typical of the Schizaeales. Two specimens of these fertile pinnae have Pekinopteris pinnules laterally attached at their bases. This newly recognized material clearly indicates that Pekinopteris was a schizaealean fern with an elongate, dimorphic fertile pinna. Apparently, the fertile pinna was easily detached from the rest of the frond during fossilization. Its combination of character states may indicate that Pekinopteris has an intermediate position between the extinct Cynepteridaceae and modern schizaealean families.
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1 - University of South Alabama, Biological Sciences, Life Sciences Building 124, Mobile, AL, 36688, United States
2 - George Mason University, Department of Environmental Science and Policy 5F2, Fairfax, Virginia, 22030, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Superior A/Cliff Lodge - Level C
Date: Wednesday, July 29th, 2009
Time: 8:15 AM