early south American grasses (paleocene - eocene) occupied forested ecosystems

STILES, ELENA; STROMBERG, CAROLINE,; CANARES, BRIELLE; ERRA, GEORGINA,; GELFO, JAVIER N., ; GOIN, FRANCISCO,

Encuentro; Botany 2023 One world; 2023

Grasses (Poaceae) exhibit exceptional taxonomic and ecological diversity, with grassland-dominated habitats around the world covering about 40% of Earth’s land surface. Modern grasslands occur in a range of temperate to tropical ecosystems, spanning low to high altitudes, and temperatures, and wet to arid climates. However, because of the scant fossil record of grasses before the global Oligocene-Miocene spread of grasslands, the ecology of early grasses and their environmental affinities remain poorly understood. We analyze phytolith assemblages extracted from sediment samples collected in Paleocene-Eocene Rio Chico Group sites along the San Jorge Basin of Argentine Patagonia to reconstruct the vegetation type early grasses occurred in. The coastal lowland deposits of the Las Violetas and Las Flores formations of the Rio Chico Group, dated from 57.9±1.1 Ma to