INVESTIGADORES
CARLINI Alfredo Armando
artículos
Título:
Decoupling the spread of grasslands from the evolution of grazer-type herbivores in South America
Autor/es:
STRÖMBERG C.; DUNN R.; MADDEN R.H.; KOHN M.; CARLINI A.A.
Revista:
NATURE COMMUNICATIONS
Editorial:
Macmillan Publishers Limited
Referencias:
Año: 2013 vol. 2013 p. 1 - 8
ISSN:
2041-1723
Resumen:
The evolution of high-crowned cheek teeth (hypsodonty) in herbivorous mammals during the
late Cenozoic is classically regarded as an adaptive response to the near-global spread of
grass-dominated habitats. Precocious hypsodonty in middle Eocene (B38 million years (Myr)
ago) faunas from Patagonia, South America, is therefore thought to signal Earth?s first
grasslands, 20 million years earlier than elsewhere. Here, using a high-resolution, 43?18
million-year record of plant silica (phytoliths) from Patagonia, we show that although
open-habitat grasses existed in southern South America since the middle Eocene (B40Myr
ago), they were minor floral components in overall forested habitats between 40 and
18Myr ago. Thus, distinctly different, continent-specific environmental conditions
(arid grasslands versus ash-laden forests) triggered convergent cheek?tooth evolution in
Cenozoic herbivores. Hypsodonty evolution is an important example where the present is an
insufficient key to the past, and contextual information from fossils is vital for understanding
processes of adaptation.