Manchester, Steven R. , Chen, Judy Iju .
The Grape Escape: Rapid geographic spread of Vitaceae in Europe and North America documented by Eocene fossil seeds.
Vitaceae are relatively common and abundant in Eocene floras of North America and Europe. We have reviewed this fossil record with attention to Early and Middle Eocene sites having especially well-preserved fossils. Most of the seeds conform morphologically to the extant genera Ampelopsis, Ampelocissus, Parthenocissus, and Vitis, but some extinct character states, relating to seed coat thickness and number of seeds per fruit, occur in a few instances. Multiple species, and often more than one genus, occur together at individual sample sites in the Early Eocene of Virginia (2 spp.), and London Clay (12 spp.), and in the Middle Eocene of Oregon (9 spp.), and Messel, Germany (9 spp.). Compressed fruits with intact seeds of Vitis or Ampelopsis from the Middle Eocene Bridger Formation in southwestern Wyoming show 12 or more seeds per berry (contrasting with modern fruits of the family rarely exceeding 4 per berry. Palaeovitis Chandler from the London Clay flora, and Ampelocissus wildei from Messel both differ strikingly from all extant seeds surveyed, in much greater thickness of the sclerified seed coat, yet in other aspects of their morphology, they conform closely to extant Vitis and Ampelocissus, respectively. The other fossils examined show seed coat thickness in the same range as extant representatives. The observed taxonomic diversity and abundance of Vitaceae in the Early to Middle Eocene of North America and Europe contrasts with the apparent absence of this family in the Cretaceous fossil record and very rare representation in the Paleocene. It is likely that climatic warming near the Paleocene-Eocene boundary brought about conditions favorable for the rapid expansion of this family via the North Atlantic Land Bridge.
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1 - Florida Museum of Natural History, Dickinson Hall, P.O. Box 117800, Gainesville, Florida, 32611, USA
2 - Department of Biology, University of Florida, Gainesville, Florida, 32611, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood D/Snowbird Center
Date: Wednesday, July 29th, 2009
Time: 8:00 AM