Abstract Detail

Paleobotanical Section

Hermsen, Elizabeth J. [1], Gandolfo, Maria [2], Wilf, Peter [3], Cuneo, Nestor [4], Johnson, Kirk R. [5], Iglesias, Ari [6].

New angiosperm reproductive structures from the early Eocene Laguna del Hunco flora, Chubut Province, Argentina.

The Laguna del Hunco flora is a highly diverse series of fossil localities that occur in tuffaceous sediments interpreted as having been deposited in an ancient caldera lake about 51-52 million years ago (an interbedded tuff has an ⁴⁰Ar/³⁹Ar date of 51.9 + 0.2 Ma). Specimens from the Laguna del Hunco flora were first described by E.W. Berry in 1925 and by others in a handful of papers published in the twentieth century from small and poorly constrained collections. More recent collecting over the last decade (1999-2009) has resulted in improved understanding of the context and composition of the flora, including its absolute age, depositional environments, paleoecology, and taxonomic diversity, which far exceeds 200 species of plants (more than four times what was previously known) from well over 6000 specimens. The flora bears a large number of often exquisitely-preserved specimens representing both previously described and undescribed taxa distributed across an array of plant groups and organ types—including bryophytes, pteridophytes, conifers, and angiosperms— as well as insect and vertebrate fossils. Work on the systematics of the flora to date includes descriptions of fossil insects and gymnospermous and angiospermous plants, often with Gondwanic biogeographic affinities and often not previously known from the South America fossil record; especially notable among these are Papuacedrus (Cupressaceae), Gymnostoma (Casuarinaceae), and several genera of proteaceous leaves and fruits. In this presentation, we focus on the large number of undescribed angiosperm reproductive remains—flowers, fruits, seeds, inflorescences, and infructescences— found in the Laguna del Hunco flora and provide preliminary taxonomic assignments for these structures where possible.

Broader Impacts:

1 - Cornell University, Department of Plant Biology, 412 Mann Library Building, Ithaca, New York, 14853-5908, USA
2 - Cornell University, LH Bailey Hortorium, Department of Pant Biology, 410 Mann Library Biulding, Ithaca, NY, 14853-4301, USA
3 - Pennsylvania State University, Department of Geosciences, University Park, PA, 16802, USA
4 - Museo Paleontológico Egidio Feruglio-CONICET, Av. Fontana 140, Trelew, Chubut, CP9100, Argentina
5 - Denver Museum of Nature and Science, Department of Earth Sciences, Denver, CO, 80205, USA
6 - Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas, 1900, La Plata, Argentina

Keywords:
Eocene
Argentina
angiosperm
Fossil
Chubut Province
Patagonia.

Presentation Type: Oral Paper:Papers for Sections
Session: 54
Location: 556A/Convention Center
Date: Wednesday, August 4th, 2010
Time: 10:30 AM
Number: 54001
Abstract ID:527