Paleoecology of the Paucituberculata and Microbiotheria (Mammalia, Marsupialia) from the late early Miocene of Patagonia.

ABELLO, ORTIZ-JAUREGUIZAR Y CANDELA

Early Miocene Paleobiology in Patagonia: high-latitude paleocommunities of the Santa Cruz Formation

Cambridge University Pres

Año: 2012; p. 156 - 172

ABSTRACT This contribution presents a paleoecological analysis of Santacrucian non-carnivorous marsupials in the orders Paucitubeculata and Microbiotheria orders. Different ecological niches for these taxa were inferred from estimates of body mass, diet, and locomotor behavior. Body masses were established using a regression analysis from living marsupials. Possible dietary preferences were explored by an analysis of the development of molar shearing. Inferences of locomotor behaviors, of some species with well-preserved postcranial skeleton, were derived from a morphofunctional analysis. From the wide range of estimated body masses, diet and locomotion of Santacrucian non-carnivorous marsupials, several niches were inferred: small to medium-sized cursorial or curso-saltatorial insectivores and small to large scansorials or arboreal frugivores and insectivore-frugivores. Paucituberculata and Microbiotheria of Santa Cruz Formation constitute an ecologically diverse assemblage that is compatible with their having lived in forested subtropical [by definition, this place was extra-rtopical—outside the tropics]  habitats for Santacrucian paleoenvironment. Forested habitats could have supported the various marsupial niches offering diverse resources in the spatial and trophic dimensions. Our reconstruction is at variance with  previous paleoecological reconstructions that proposed more ‘open’, e.g., less forested, habitats for Santacrucian paleoenvironment. Perhaps the ecological diversity reported here may be an expression of environmental patchiness with presence of some forested habitats.