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Abstract Detail


Paleobotanical Section

Benca, Jeff P. [1], Strömberg, Caroline A. E. [1], Carlisle, Maureen H. [2].

Intra versus interspecific variation in the Devonian lycopsid genus Leclercqia and the designation of a novel species from the Chilliwack Group of Washington state.

Protolepidodendraceaen lycopsids were among the most conspicuous and readily identifiable components of late Early-Middle Devonian terrestrial plant communities. The most widespread and best known genus, Leclercqia, had a vast biogeographic range, inhabiting both Gondwana and Euramerica. For this reason, Leclercqia has been incorporated as a biological indicator for the proximity of the continents during the late Early-Middle Devonian. Despite its contributions to the reconstruction of Devonian ecosystems and plate tectonics, only two species have been described to date (L. complexa and L. andrewsii). The Northwest Lime Quarry, a new Middle Devonian fossil locality in the Chilliwack Group of northern Washington State, constitutes the westernmost record for its distribution in North America, and has also yielded a new morphotype for the genus. To distinguish this new morphotype, we developed a series of morphometric measurements capturing microphyll size, shape, main axis, and sporangia. These measurements were analyzed to assess the morphological and potential taxonomic diversity within Leclercqia globally. Analysis of Variance (ANOVA) of measurements normalized by size (axis width) shows that the new morphotype from the Chilliwack Group is statistically significantly different from both L. complexa and L. andrewsii in five out of eleven characters, L. complexa in seven characters, and L. andrewsii in nine characters. L. complexa shows statistically significant differences from L. andrewsii in seven of the characters measured. Multivariate techniques (Principal Component Analysis, Linear Discriminant Analysis) using vegetative characters similarly separate the new morphotype from L. complexa; L. andrewsii could not be analyzed due to incomplete data. Based on these results, we suggest the addition of a new species to the genus: Leclercqia scolopendra. This study constitutes one of the first extensive morphometric analyses of Devonian lycopsids and indicates that morphometrics may be a potentially valuable method for analyzing taxonomic diversity and morphological disparity in lycopsid clades in deep time.

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1 - University of Washington, Department of Biology & Burke Museum, Box 351800, 24 Kincaid Hall, Seattle, WA, 98195, USA
2 - Burke Museum, University of Washington, Box 353010, Seattle, WA, 98195-301, USA

Keywords:
lycopsid
morphometrics
Leclercqia
Washington
Middle Devonian.

Presentation Type: Oral Paper:Papers for Sections
Session: 4
Location: 555B/Convention Center
Date: Monday, August 2nd, 2010
Time: 8:45 AM
Number: 4002
Abstract ID:490


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