Didelphidae marsupials (Mammalia, Didelphimorphia) from the late Pleistocene deposit of the Gruta dos Moura Cave, northern Brazil.

Patricia Villa Nova,Leonardo S Avilla,Édison V Oliveira

doi:10.1590/0001-3765201520140229

Abstract

The present study acknowledges the diversity of fossil marsupials from the Gruta dos Moura cave, as well as environmental and climatic aspects during the Quaternary. The results show that this is the largest diversity of Pleistocene marsupials recorded in a single cave: Didelphis albiventris, D. aurita, Gracilinanus agilis, G. microtarsus, Marmosa murina, Monodelphis brevicaudata, M. domestica and Sairadelphys tocantinensis. Furthermore, the described specimens are also part of the only fossil assemblage unequivocally referable to the late Pleistocene. Paleontological studies suggest an intimate association with dry and open environments with high abundance of water sources. Since most of the identified taxa are characteristic of open forests and gallery forests, this could represent the actual environment around the Gruta dos Moura cave. Recent studies identified sympatric occurrences between species from open and dry environments and species from humid forests that were identified among our material and are characteristic of humid regions. Therefore, these species could inhabit gallery forests and capons, or even ecotones, inside a dry and open environment. Moreover, the extinction of Sairadelphys could also indicate that the climatic and environmental conditions changed or that the past environment was more heterogeneous than the current environment of the region.

Highlights

Extant South American marsupials are included in two lineages: Ameridelphia and Australidelphia
The stratigraphically controlled survey of the described material ensures that all the specimens from Gruta dos Moura cave partially represents the diversity of didelphids that synchronously inhabited the area nearby the cave. We assume that this is a partial diversity because there are few paleontological studies which could certify that the assemblage of a given cave represents the mammal diversity of a region, since the fossilization is a rare process which depends on several factors, especially the taphonomic factors
The disintegration of the block revealed that there was a taphonomic selection by size, where only fragments of small vertebrates, especially mammals, including rodents (Tobelem et al 2013), bats (Avilla et al 2013) and marsupials (Villa Nova and Avilla 2013), were preserved

Summary

Introduction

Extant South American marsupials are included in two lineages: Ameridelphia and Australidelphia. While Ameridelphia is highly diverse in this continent, Australidelphia is represented only by the microbiotherid Dromiciops gliroides The first records of didelphid marsupials are from the late Cretaceous of North America, and from the Paleocene of South America (Pascual 1980). During the Miocene the Didelphidae became extinct in North America but reoccupied that continent during the Great American Biotic Interchange (Reig et al 1987, Marshall et al 1990)

Methods

Results

Conclusion