Phipps, Carlie J. , Upchurch, Garland , Oxley, F. M. .
A preliminary survey of fungal biodiversity across the Cretaceous-Tertiary boundary, Raton and Denver basins, USA.
Studies of the Cretaceous-Tertiary (K-T) boundary have provided evidence for mass-mortality and the rapid extinction of many species and genera across kingdoms, particularly in animals and plants. For fungi, however, many authors have noted rapid extinction in North America of Dothideomycetes assignable to the genus Trichopeltinites, but otherwise have written little about the effects of the K-T boundary on fungal diversity. Preliminary analysis of fungi in leaf megafossil and phytodebris assemblages from the Raton and Denver basins indicates an abundant record of ascomycetes across the K-T boundary and the potential to unravel the effects of host plant extinction and environmental change on fungal diversity. Latest Cretaceous assemblages are characterized by a variety of genera within Microthyriaceae, but especially by the abundant occurrence of fruiting bodies assigned to the genus Trichopeltinites. These occur on multiple leaf species and differ from Tertiary specimens of Trichopeltinites in having both central ascomata and distinct thickened marginal structures. Also present in latest Cretaceous assemblages are multiple species of cleistothecia and perithecia/pycnidia, angiosperm cuticles with stomata occluded by hyphae, isolated hyphae and more complex fungal tissues, and multicellular ascomycete spores. Early Paleocene fungal assemblages, while variable in terms of preservation and diversity, are characterized by abundant Callimothallus, Phragmothyrites, Asterothyrites, and other genera of shield-shaped fruiting bodies of Microthyriaceae known from the Cretaceous of the Raton and Denver basins and other regions. Also present are fungal germlings, multiple species of cleistothecia and perithecia/pycnidia (some with appendages), and several isolated hyphal and spore types. The abundant occurrence of fungal specimens in association with leaf cuticles from the latest Cretaceous and early Paleocene provide the types of samples needed to elucidate the effects of the K-T boundary event on fungi and the correlation of fungal diversity with plant diversity and extinction.
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1 - State University of New York Institute of Technology, Department of Math/Science, P.O. Box 3050, Utica, New York, 13504-3050
2 - Texas State University, Department of Biology, 601 University Drive, San Marcos, Texas, 78666, USA
3 - Texas State University, Department of Biology, 601 University Drive, San Marcos, Texas, 78666, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Lake Erie/Hilton
Date: Tuesday, July 10th, 2007
Time: 11:30 AM