INVESTIGADORES
PREVOSTI Francisco Juan
congresos y reuniones científicas
Título:
The Cenozoic terrestrial mammalian predator guild in South America: the results of the most recent land connection between the Americas
Autor/es:
FORASIEPI, ANALIA; PREVOSTI, FRANCISCO J.; ZIMICZ, N.
Lugar:
General Roca
Reunión:
Simposio; Simposio: "Istmos y rutas maritimas: las conecciones biogeograficas en el Hemisferio Sur a travez del tiempo"; 2011
Resumen:
<!--
@page { margin: 2cm }
P { margin-bottom: 0.21cm }
-->
The
Cenozoic terrestrial mammalian predator guild in South America: the
results of the most recent land connection between the Americas
A.M.
FORASIEPI1,
F. J. PREVOSTI2,
and N. ZIMICZ3
During
most of the Cenozoic, the carnivore adaptative zone in South America
was filled by crocodiles (Sebecidae), snakes (Madtsoiidae), birds
(Phorusrhacidae), and metatherian mammals (Sparassodonta). Since the
Huayquerian, eutherian mammals (Carnivora) started to occupy the
niche, becoming today the principal component. Several authors have
suggested that the ingression of the Carnivora caused the decline and
extinction of the Sparassodonta, because they putatively competed.
With the intention of testing this hypothesis, we collect data about
diversity, first and last appearances, and estimate size and diet.
Sparassodonta is known by 58 species, registered from the Tiupampan
to the Chapadmalalan. The taxa had different sizes and mostly a
hypercarnivorous diet. The
diversity is low (five
taxa or less) during most ages; the highest number is found in the
Santacrucian (eleven species).
In South America, Carnivora is known by 82
terrestrial taxa, of which 37 are extinct and 45 are living species.
They were
represented by four or less species from the Huayquerian to
Marplatan, reaching values of about 20 species only in the Ensenadan.
Carnivora was first represented by small, omnivore species, with
large omnivores first appearing in the Chapadmalalan. There was
overlap of carnivorous groups during the Huayquerian-Chapadmalalan,
but there does not appear to have been ecological one. This does not
support the competitive displacement hypothesis and is more in line
with an opportunistic ecological replacement. The decline and
extinction of the Sparassodanta appear to be part of a larger
faunistic change in which intrinsic (biological)
and external (physical) factors
are combined.