IADIZA   20886
INSTITUTO ARGENTINO DE INVESTIGACIONES DE LAS ZONAS ARIDAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Geographical distribution and diversification in South American Octodontid Rodents (Rodentia, Caviomorph).
Autor/es:
OJEDA, A. A., NOVILLO, A. RICARDO A OJEDA AND SERGIO A ROIG-JUÑENT.
Lugar:
Mendoza, Argentina
Reunión:
Congreso; 10 th International Mammalogical Congress.; 2010
Institución organizadora:
GIB - IADIZA
Resumen:
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The Octodontidae family is a characteristic group of rodents inhabiting South
American aridlands and scrublands. The octodontids date back to late Miocene
(7.79 Mya) with a major diversification during the Plio-Pleistocene. This is an
ecomorphologically diverse group, composed of 13 species, from aboveground
generalists to subterranean specialists, with their geographical ranges extending
along both sides of the Central-Southern Andes. In this presentation we propose
a biogeography hypothesis for their major clades and explore the evolutionary
history of their ecological characters (e.g. modes of life). We used a
phylogeny of 11 Octodontids; distributional ranges were estimated from Nature
Server Database and recent literature. Geographical regions were based on WWF
Terrestrial Ecoregions. We used DIVA program to identify putative ancestral
areas for each node. This, together with the divergence time estimated for this
group, served to compare with known events of plate tectonic movements, Andean
uplift, and major climate changes from Plio-Pleistocene to Holocene. Parsimony
ancestral reconstruction for ecological character was performed using Mesquite
program. Our results show that the ancestral area (i.e. ecoregions) for the Octodontidae
group includes the Northern Monte, Mediterranean shrubland, central Puna and the
Andean steppe. Two vicariant events occurred during its evolution. One corresponds
to the Andean uplift which separated the Argentinean and Chilean octodontids. The
second was associated with important volcanic activity in the Andean Puna, which
separated O. gliroides from Chilean group. Divergence of Chilean octodontids was
characterized by more recent dispersion and extinction. Terrestrial habits are
suggested as the ancestral mode of life whereas fossoriality and semifossorial habits
could be associated to new habitat types which emerged after the Andean
uplift. We highlight the role of the Andes and associated environmental changes
in the biogeography and ecology of this lineage ( Partially supported by grants
from CONICET (PIP 5944) and AGENCIA (PICT 11768).