MSA - Systematics/Evolution
Widhelm, Todd , Egan, Robert S. , Livshultz, Tatyana , Lumbsch, H. Thorsten .
Testing Species Delimitations in the Parmotrema peforatum group (Parmeliaceae, Ascomycota) in Eastern North America.
The current taxonomy of the Parmotrema perforatum group of lichens recognizes six closely related species divided into three species pairs, a pair comprising one apotheciate and one sorediate species. Each pair is characterized by a distinct combination of secondary metabolites. Previous studies based on morphology and chemistry hypothesized that the three apotheciate chemotypes are reproductively isolated sibling species, and that each sorediate species evolved independently from the chemically identical apotheciate species. This species delimitation was reexamined using DNA sequence data of two nuclear loci, glyceraldehyde-3-phosphate dehydrogenase (GPD) and ITS, from individual thalli from populations in Texas and Louisiana with selected sequences from MS456 and MS277. We used population aggregation analysis and a cohesion species approach to test species boundaries in the Parmotrema perforatum group. There was no correlation of reproductive mode (apothecia or soredia) and allele lineages found in the gene trees, suggesting that sorediate thalli are part of the same sexually reproducing populations as apotheciate thalli. While some norstictic acid individuals were polymorphic for stictic acid, presence of chemosyndromes is correlated with distinct allele lineages and suggests that two species can be distinguished based on different chemosyndromes (presence of either norstictic acid or alectoronic acid).
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1 - University of Nebraska Omaha, Department of Biology, 114 Allwine Hall, Omaha, Nebraska, 68182-0040, USA
2 - Academy of Natural Sciences of Philadelphia, Botany Department, 1900 Benjamin Franklin Parkway, Philadelphia, PA, 19103-1101, USA
3 - Field Museum of Natural Hististory, Department of Botany, 1400 South Lake Shore Drive, Roosevelt Rd At Lake Shore, Chicago, Illinois, 60605-2496, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood A/Snowbird Center
Date: Tuesday, July 28th, 2009
Time: 10:15 AM