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Abstract Detail



Paleobotany

Zhu, Hai [1], Manchester, Steven [2], Lott, Terry [3].

Illigera fruit from the Miocene Alum Bluff, northwestern Florida.

Being one of the rare Miocene floras yielding both macro- and micro-fossils in eastern North America, the middle Miocene Alum Bluff flora in northwestern Florida is significant for a better understanding of the floristic diversity and environment during geological time and the forming of modern flora. The Alum Bluff paleoflora has been known mainly by deciduous subtropical to temperate taxa. No tropical megafossils have been reported from this flora prior to this study despite the scarce noise of the possibility of tropical affinity. Here, we first report a newly discovered fossil winged fruit of Illigera (Hernandiaceae), a genus with modern tropical distribution, from this flora. Detailed morphological comparison supports the establishment of a new fossil species, Illigera berryi Zhu, Manchester et Lott. It augments our understanding of the floristic diversity and verifies the presence of tropical components in the Alum Bluff paleoflora. Furthermore, I. berryi extends the fossil history of Illigera in North America further to the middle Miocene, since the first discovery of the genus, I. eocenica, from Eocene of that continent. This demonstrates that the genus has survived living in eastern North America at least to the middle Miocene during the severe climatic deterioration in Miocene. Combined with the recent new fossil occurrence of I. eocenica from Eocene of Tibet, it indicates that Illigera may have originated from Northern Hemisphere and had a wider distribution than was previously interpreted. The cooling and drying climate since the Miocene may have forced the genus a southward retreat. However, more fossils are in needed for a better understanding of the tropical affinity of Alum Bluff flora as well as for a thorough interpretation of the plant diversity of Illigera during geological past.


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1 - Shangrao Normal University, College Of Life Science, 401 Zhimin Road, Xinzhou District, Shangrao, Jiangxi, 334001, China
2 - Florida Museum of Natural History, Dickinson Hall, Museum Rd & Newell Dr. Gainesville, Gainesville, FL, 32611, USA
3 - Florida Museum Of Natural History, Museum Road & Newell Drive, Dickinson Hall, Gainesville, FL, 32611, United States

Keywords:
eastern North America
Fort Preston Formation
Hernandiaceae
megafossil
winged fruit
Tropical.

Presentation Type: Oral Paper
Session: TBA
Location: /
Date: Thursday, January 1st, 1970
Time: TBA
Number:
Abstract ID:837
Candidate for Awards:Isabel Cookson Award


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