Systematics Section / ASPT
Burge, Dylan , Manchester, Steven R. .
Fossil history and biogeography of Paliurus (Rhamnaceae).
The genus Paliurus, recognized by its distinctive winged fruit, is well represented in the fossil record of the Northern Hemisphere. Fruits assignable to Paliurus are known from the Tertiary of North America, Europe, and Asia, while extant species are limited to Eurasia. We examined infrageneric variation in fruit morphology among the extant species as a basis for interpreting fossil fruits. We present a synopsis of fossil fruit records for the genus, suggest taxonomic changes, provide new records, describe the oldest known members of the genus from the early Eocene of North America, and discuss biogeographic and phylogenetic implications. Fossil Paliurus fruits are diverse in size, shape, and sculpture. However, there are few consistent criteria for demarcating species within the continuum represented by fruit morphology. Based on morphometric analysis, we suggest synonymy of most European, Asian, and North American fossil Paliurus fruits under the name Paliurus favonii Unger, within which several potential segregates exist. The P. favonii morphotype is known from the Eocene and Miocene of North America, the Oligocene and Miocene of Europe, and the Eocene through Pleistocene of Asia. New records of P. favonii are reported here from the Miocene and late Eocene of North America, and a new species with a broader wing from the middle Eocene of Oregon, and also possibly of Wyoming, is introduced. The high diversity of fossil forms during the Eocene through Miocene of Europe, Asia, and North America indicates early diversification and range expansion for the genus, followed by range contraction, and extinction in North America by¬†the close of the Miocene. Published molecular phylogenetic trees are calibrated using the minimum age for Paliurus based on the fossil record, yielding a range of absolute time estimates for the diversification of the family Rhamnaceae.
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1 - Duke University, Department of Biology, 139 Biological Sciences Building, PO Box 90338, Durham, North Carolina, 27708, USA
2 - Florida Museum of Natural History, Dickinson Hall, P.O. Box 117800, Gainesville, Florida, 32611, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Stevens 3/Hilton
Date: Wednesday, July 11th, 2007
Time: 9:15 AM