Late Pleistocene echimyid rodents (Rodentia, Hystricognathi) from northern Brazil.

Thais M.F Ferreira,Leonardo S Avilla,Leonardo Kerber,Rodrigo P Dutra,Adriana Itati Olivares

doi:10.1590/0001-3765201620150288

Abstract

Echimyidae (spiny rats, tree rats and the coypu) is the most diverse family of extant South American hystricognath rodents (caviomorphs). Today, they live in tropical forests (Amazonian, coastal and Andean forests), occasionally in more open xeric habitats in the Cerrado and Caatinga of northern South America, and open areas across the southern portion of the continent (Myocastor). The Quaternary fossil record of this family remains poorly studied. Here, we describe the fossil echimyids found in karst deposits from southern Tocantins, northern Brazil. The analyzed specimens are assigned to Thrichomys sp., Makalata cf. didelphoides and Proechimys sp. This is the first time that a fossil of Makalata is reported. The Pleistocene record of echimyids from this area is represented by fragmentary remains, which hinders their determination at specific levels. The data reported here contributes to the understanding of the ancient diversity of rodents of this region, evidenced until now in other groups, such as the artiodactyls, cingulates, carnivores, marsupials, and squamate reptiles.

Highlights

The living members of Hystricognathi (Rodentia: Hystricomorpha) include three lineages: the African phiomorphs, represented by four extant families, the Old World teeth
We present here the first data on the late Pleistocene diversity of echimyids from the Gruta dos Moura limestone cave in Aurora de Tocantins, low latitudes of South America
The studied material was collected from a carbonate deposit, which was found in a block at the wall of the main room of the Gruta dos Moura limestone cave in Aurora de Tocantins (12o42’47” S and 46o24’28” W), State of Tocantins, northern Brazil (Figure 1)

Summary

Introduction

The living members of Hystricognathi (Rodentia: Hystricomorpha) include three lineages: the African phiomorphs, represented by four extant families (the three classical families plus Heterocephalidae; Patterson and Upham 2014), the Old World teeth (sensu Mones 1968). Echimyids have an extended fossil record, but some controversies remain about the age of the family. Molecular studies date their origin back to the early Miocene (Upham and Patterson 2012, Fabre et al 2012, Voloch et al 2013) while the fossil record could be even older (e.g. late Eocene, Frailey and Campbell 2004; late Oligocene, Verzi et al 2014). It is worth noting that Paleogene echimyids require cladistic analyses to assess their relationships with modern forms (Carvalho and Salles 2004, Verzi et al 2014, 2016)

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