Herrera, Fabiany , Manchester, Steven , Carvalho, Monica , Correa, Edwin , Jaramillo, Carlos .
Permineralized fruits and seeds from the Early Middle Miocene Cucaracha Formation of Panama.
New exposures of the early Middle Miocene Cucaracha Formation (~17-19.5Ma) from the Panama Canal, about 20 km northwest of Panama City, have yielded a rich deposit of well-preserved permineralized fruits, seeds and woods. This flora provides the opportunity to investigate the plants that vegetated Central America prior to establishment of the physical connection between North and South America, and complements previous paleobotanical investigations of the Mid-Miocene Climatic Optimum in this region, based exclusively on spores and pollen. Disseminules are exposed by breaking the calcium carbonate-permineralized coarse sandstone with hammers or a hand-operated screw driven rock splitter. Specimens retrieved by fracturing in this way are investigated in the broken surfaces by light and/or scanning electron microscopy, then reassembled with cyanoacrylate glue for further analyses. Both external and internal structure and anatomy are further documented by serial sectioningwith a thin diamond blade, and/or peeling with the acetate peel technique. Families and genera recognized from this carpoflora include Anacardiaceae (Spondias, Pentoperculum), Annonaceae, Arecaceae, Cannabaceae, Chrysobalanaceae (Parinari), Euphorbiaceae, Fabaceae, Humiriaceae (Sacoglottis), Icacinaceae (Phytocreneae tribe), Lauraceae, Myristicaceae, Passifloraceae, and Vitaceae (Cissus). Numerous other fruit and seed types are present, bringing the currently recognized diversity to at least thirty species, compared with 19 documented previously by Alan Graham from pollen. These representatives emphasize the woody component of the flora-mainly trees, shrubs and lianas, whereas the palynological work revealed nine kinds of ferns as well as potentially woody plants (Euphorbiaceae (Alchornea), Juglandaceae (Alfaroa/Oreomunnea), Leguminosae(Crudia), and Rhizophoraceae). The combined floristic data indicate a warm and wet climate during the middle Miocene in Panama,contrary to previous paleoclimatic estimates based on paleosols which suggested very dry and cool conditions during the deposition of the Cucaracha Formation.
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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 - Cornell University, Dept Of Geoscience, 412 Mann Library Building, Ithaca, NY, 14853, USA
4 - McGill University, McGill University, Montreal, QU, H3A 0G4 , Canada
5 - Smithsonian Tropical Research Institute, Balboa, Ancon, 0843-03092, Panama
Presentation Type: Oral Paper:Papers for Sections
Location: Union A/Hyatt
Date: Wednesday, July 11th, 2012
Time: 11:30 AM