INVESTIGADORES
SOIBELZON Leopoldo Hector
congresos y reuniones científicas
Título:
PALEOECOLOGY AND EVOLUTION OF THE CARNIVOROUS MAMMALIAN FAUNAS OF SOUTH AMERICA FROM THE LATE MIOCENE TO THE PLEISTOCENE: INSIGHTS FROM STABLE ISOTOPIC SIGNATURES (13C, 15N, 18O) IN FOSSIL BONES AND TEETH
Autor/es:
COTTE, M; PREVOSTI, F.; SOIBELZON, L.H.; BOCHERENS, H
Reunión:
Congreso; 23rd Latin American Colloquium LAK 2014; 2014
Resumen:
South
America was isolated during most of the Tertiary and developed a very
particular mammalian fauna. In contrast to other continents, the carnivore
adaptive zone was filled by crocodiles, large snakes and birds, and metatherian
mammals (Sparassodonta). Sparassodonta was diverse during the Tertiary with a
broad range of sizes (≈ 2-50 kg). This diversity decreased towards the late
Miocene and the group became extinct at the middle Pliocene (≈ 3 Ma). The cause
of this decline and extinction may have been immigration of placental
Carnivores to South America (≈ 6-7 Ma ago), which putatively competed with the
sparassodonts (Ecological Competitive Displacement Hypothesis, ECD). This
hypothesis was recently criticized and the Ecological Replacement (ER)
hypothesis was proposed, which postulates that newcomers (placental carnivores)
filled ecological niches left empty after the extinction of previous occupants
(marsupial carnivores) due to other causes, such as environmental changes. This
subject is currently being studied using morphometrics, which, however, may be
biased by a phylogenetic signal. Here we propose using stable isotopes (13C,
15N, 18O) to complement the study of the evolution of the
carnivore guild during the late Cenozoic in Argentina. This purely phenotypic
approach will yield direct information on actual ecological changes. Under the
ER scenario, environmental changes should lead to changes in the isotopic
relationships among fossil taxa, while in the ECD scenario, similar isotopic
relationships should be observable between extinct marsupial predators and the
placental predators that replace them.