title: High plant diversity in Eocene South America: evidence from Patagonia.
abstract: Tropical South America has the highest plant diversity of any region today, but this richness is usually characterized as a geologically recent development (Neogene or Pleistocene). From caldera-lake beds exposed at Laguna del Hunco in Patagonia, Argentina, paleolatitude approximately 47 degrees S, we report 102 leaf species. Radioisotopic and paleomagnetic analyses indicate that the flora was deposited 52 million years ago, the time of the early Eocene climatic optimum, when tropical plant taxa and warm, equable climates reached middle latitudes of both hemispheres. Adjusted for sample size, observed richness exceeds that of any other Eocene leaf flora, supporting an ancient history of high plant diversity in warm areas of South America.
authors.affiliation: Department of Geosciences, Pennsylvania State University, University Park, PA 16802, USA. pwilf@geosc.psu.edu
authors.forename: Peter
authors.initials: P
authors.lastname: Wilf
authors.forename: N Rubén
authors.initials: NR
authors.lastname: Cúneo
authors.forename: Kirk R
authors.initials: KR
authors.lastname: Johnson
authors.forename: Jason F
authors.initials: JF
authors.lastname: Hicks
authors.forename: Scott L
authors.initials: SL
authors.lastname: Wing
authors.forename: John D
authors.initials: JD
authors.lastname: Obradovich
mesh_terms: D001118:Argentina; D002980:Climate; D004463:Ecology; D017753:Ecosystem; D005580:Fossils; D019015:Geologic Sediments; D009656:North America; D063245:Plant Development; D018515:Plant Leaves / Q000033:anatomy & histology; D010944:Plants / Q000145:classification; D011891:Rain; D013020:South America; D013696:Temperature; D014329:Tropical Climate