Abstract Detail

Paleobotanical Section

Herrera, Fabiany [1], Manchester, Steven  [2], Jaramillo, Carlos [3].

Revealing the Floristic and Biogeographic Composition of Paleocene to Miocene Neotropical Forests.

Most prior studies of the Neotropical fossil record have focused on pollen and leaf remains. While these studies provide valuable insight into patterns of diversity and climate change, the resolution of taxonomic affinities has been at a coarse level. Fossil fruits and seeds provide additional characteristics of systematic significance. Confident identification of the floristic composition is key to understanding varying biogeographic patterns and the response of vegetation to tectonic changes. We are investigating selected, well-preserved carpofloras ranging from ~60 to ~19 Ma. from the Paleocene, Eocene, Oligocene and Miocene of Central America and northern South America (specifically Colombia, Peru, and Panama) to address the following major questions: 1) What plant families or genera from northern South America show biogeographic connection with other land masses during the late Paleocene? 2) Were wind-dispersed fruits and seed common elements in Paleocene Neotropical rainforests? 3) What families or genera first colonized the emergent land in the Panamanian volcanic arch during the late Eocene? 4) Do the fossil plants from the Oligocene of Peru show any biogeographic connection with the remaining South American region? 5) Did the Miocene Panamanian seaway act as a strong biogeographic barrier between South American and Central American forests? Results show that the Paleocene floras in Colombia reached a moderate, diverse array of winged fruit and seed types and modes of dispersal after the Cretaceous extinction. Although northern South America was isolated geographically, several fossils in Menispermaceae and Ulmaceae show connection with North American paleofloras and extant Old World taxa. Some of the new colonizing plant families identified from late Eocene of Panama include Arecaceae, and the earliest Vitaceae and Humiriaceae in the Neotropics. At the generic level we have identified Dracontomelon and Leea, both of which are restricted today to Old World tropical rainforests. From Peru, some of the new Oligocene Belen taxa include endocarps of Duckesia (Humiriaceae), a genus endemic today to eastern Amazonia. Finally, from the early Miocene of Panama we have identified among others Sacoglottis, Parinari, Cissus, and Heliconia, suggesting that long distance dispersal between Central and South America was very common before the closing of the Panamanian Seaway.

1 - Florida Museum Of Natural History-University Of Florida, Biology-Paleobotany, Dickinson Hall, Museum Rd & Newell Dr, Uiversity Of Florida Campus, Gainesville, FL, 32611, USA
2 - University of Florida, Florida Museum of Natural History, PO Box 117800, Gainesville, FL, 32611, USA
3 - Smithsonian Tropical Research Institute, CTPA, Ancon, Panama City, Panama

Keywords:
fossils
Fruits
Seeds
Paleobiogeography
Neotropical
Paleocene
Eocene
Oligocene
Miocene.

Presentation Type: Oral Paper:Papers for Sections
Session: 8
Location: Whitewater/Grove
Date: Monday, July 28th, 2014
Time: 1:45 PM
Number: 8016
Abstract ID:286
Candidate for Awards:Isabel Cookson Award,Maynard F. Moseley Award