Nagalingum, Nathalie , Cantrill, David J. .
Ferns in the freezer: Early Cretaceous (Albian) ferns from Alexander Island, Antarctica.
The Early Cretaceous (Albian) flora of Alexander Island, Antarctica, comprises a diverse assemblage of liverworts, horsetails, lycophytes, ferns, bennettitaleans, ginkgoaleans, cycads, conifers, pentoxylaleans, and angiosperms. Ferns are by far the most species-rich group with 24 species recognized, and mostly preserved as sterile leaf impressions (fertile material is only available for four species). The fern assemblage includes many previously undescribed taxa and forms assignable to extant families (Osmundaceae, Gleicheniaceae, Matoniaceae, Dipteridaceae and Marsileaceae). In contrast to Cretaceous floras from Australia, South America, and elsewhere in Antarctica, the Alexander Island fern flora is especially diverse. Biogeographic comparison reveals that despite its closer proximity to South America, the Alexander Island fern flora exhibits greatest similarity to those of Australia. In order to survive in Antarctica during the Cretaceous, the Alexander Island ferns tolerated extreme cold and continuous darkness in the winter, but warm equable summers. Possible impacts of these climatic conditions on fern ecology and diversity are addressed.
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1 - Duke University & Harvard University, Biological Sciences Durham NC 27708, Arnold Arboretum 22 Divinity Avenue Cambridge MA
2 - Royal Botanic Gardens, Melbourne, National Herbarium of Victoria, Private Bag 2000, South Yarra, Victoria, 3141, Australia
Presentation Type: Oral Paper:Papers for Sections
Location: Lake Erie/Hilton
Date: Tuesday, July 10th, 2007
Time: 9:15 AM