Abstract Detail

Paleobotany

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

Illigera fruits from the Miocene of Alum Bluff, northwestern Florida.

As one of the rare Miocene floras in eastern North America yielding both macro- and micro-fossils, the Alum Bluff flora in northwestern Florida provides a good opportunity for understanding former floristic diversity and environment and the development of modern temperate flora in that area. The flora has previously been known mainly by deciduous subtropical to temperate taxa; no tropical macrofossils have been confirmed from this flora although some elements of tropical affinity were reported a century ago. Here, we report newly discovered winged fruits of the tropical genus Illigera (Hernandiaceae) from this flora. Morphological comparisons support establishment of a new fossil species, Illigera berryi Zhu, Manchester et Lott, with close similarity to the extant Asian species I. grandiflora. The new find is the first confirmed thermophilic macrofossil record from the flora and enriches its known floristic diversity there. It expands the paleogeographic distribution of Illigera in North America southeastward and extends the fossil history into the middle Miocene in that continent. This genus may have survived in that continent at least the middle Miocene since its first appearance in the Eocene of western North America. Combined with the previously recognized fossil occurrences from the Eocene of western North America and central Tibet, the fossil evidence indicates that Illigera had a wider distribution in the Cenozoic than was previously interpreted, and suggests that the genus may have originated from the Northern Hemisphere.

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: PAL1, Cookson Award Session I
Location: Virtual/Virtual
Date: Monday, July 27th, 2020
Time: 10:45 AM
Number: PAL1004
Abstract ID:837
Candidate for Awards:Isabel Cookson Award