Gensel, Patricia G. , Pigg, Kathleen B. .
An arborescent lycopsid from the Lower Carboniferous Price Formation of southwestern Virginia, USA, previously assigned to Lepidodendropsis.
A large assemblage of lycopsid compression/impression and mold-cast remains are known from a single horizon in the Lower Carboniferous Price Formation of southwestern Virginia, USA. Although these fossils were previously assigned to multiple species of Lepidodendrondropsis Lutz, they differ from this well known morphogenus by having well defined leaf scars and ligules. We demonstrate that the overlapping variability among specimens is a result of their representing different growth stages or positions in the plant, different preservational modes, and/or part-counterpart differences and conclude that the remains are part of the same plant. The Virginia plant was a tree probably attached to the plant base Protostigmaria Jennings. The trunk extended 3-4 m before branching dichotomously to produce a crown of several times divided branches, with the distal-most ones still bearing long tapering leaves. Leaf base patterns change along the length of a single stem, each morphology conforming to a different previously established species of Lepidodendropsis, with the differences reflecting what surface was preserved. Reproductive remains indicate that this heterosporous plant bore sporangia in fertile zones. This plant has a suite of morphological features not found in any currently known taxon and represents a new genus of Late Devonian-Carboniferous arborescent lycopsids. Other lycopsid remains attributed to Lepidodendropsis should be re-examined to better understand their structure and affinities. Improved knowledge about these plants may aid in elucidating diversity and phylogenetic relationships among Late Devonian-Late Carboniferous arborescent lycopsids.
This essentially is a study of a series of fossils that allow for the reconstruction of a whole plant for a time period where little is known about the aborescent members of this particular group; coupled with our interpretations that it grew in a swamp environment like the later occurring lepidodendrids makes it of interest, both ecologically and phylogenetically.
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1 - University of North Carolina, Department of Biology, Cb#3280, Chapel Hill, North Carolina, 27599-3280, USA
2 - Arizona State University, School of Life Sciences, P.O. Box 874501, Tempe, Arizona, 85287-4501, USA
whole plant reconstruction.
Presentation Type: Oral Paper:Papers for Sections
Location: 555B/Convention Center
Date: Monday, August 2nd, 2010
Time: 2:15 PM