Geological Society of America

150 Paleontology VI - Biogeography

Tuesday, 2 November 2010
8:00 AM - 12:00 PM
Room 605

PALEOGENE MACROFLORAS FROM NORTHERN SOUTH AMERICA: KEYS FOR UNDERSTANDING THE FLORISTIC COMPOSITION OF MODERN NEOTROPICAL RAINFORESTS

Paper number: 150-3
Program: Technical Sessions
Time: 8:30 AM – 8:45 AM

Authors

Fabiany Herrera Presenting Author
University of Florida, Gainesville, FL
Carlos Jaramillo
Smithsonian Tropical Research Institute, Balboa, Ancon, Panama, N/A
Monica R. Carvalho
Cornell University, Ithaca, NY
Steven Manchester
University of Florida, Gainesville, FL
S.L. Wing
Smithsonian Institution, Washington, DC
Gabriela Doria
Panama, N/A

Abstract

Three paleofloras from the Paleogene of Colombia have been collected during the last years: Cerrejón and Bogotá (middle-late Paleocene), and Upper Bogotá (early Eocene). Leaf physiognomy, reconstructed paleoclimate, intensive insect herbivory, and the floristic composition of the floras suggest widespread rainforests during the Paleocene in Colombia. These ancient rainforests exhibit the typical elements of the canopy, understory, and shrub/liana layers found in extant tropical rainforests.

The most common and abundant families/orders identified so far include: Anacardiaceae, Annonaceae, Araceae, Arecaceae, Euphorbiaceae, Fabaceae, Icacinaceae, Lauraceae, Malpighiaceae, Malvaceae, Meliaceae, Menispermaceae, Salicaceae, Sapotaceae, Zingeberales, Violaceae, six species of ferns, a cycad, and a conifer, among others. The fruit and seed morphological diversity includes a wide range of sizes and dispersal mechanisms, such as winged taxa, legume pods, and endocarps associated with fleshy fruits.

These new paleofloras from northern South America provide a new insight into the early Cenozoic evolution of Neotropical floras, and suggest that these rainforests were composed of a mixture of various biogeographical elements. These include angiosperm families and/or genera endemic to modern Neotropics and taxa currently restricted to the Paleotropics. In contrast, the ferns had more affinity with paleofloras from the Paleocene of North America.