Observações sobre a repartição espacial dos restos fósseis de preguiça-gigante (gênero Eremotherium) na Lagoa Uri de Cima, Pernambuco, Brasil

Abstract

-REMARKS ON THE SPATIAL ARRANGEMENT OF GIANT SLOTH FOSSIL REMAINS (GENUS EREMOTHERIUM)AT LAGOA URI DE CIMA, PERNAMBUCO, BRAZIL. The results of the study on spatial arrangement, the analysis of marks and the preservation conditions of the giant ground sloth (Eremotherium) remains found in the Lagoa Uri de Cima (Salgueiro, Pernambuco, Brazil), a temporary shallow lake, are presented here. The skeletal elements of the same individual, an adult, found in a restricted area (about 8 m in diameter) and its taphonomic patterns suggest that the animal arrived in the shallow lake as a carcass, and its bones were subsequently spread apart and broken mainly by trampling by other large animals. This taphonomic model also applies to some other Eremotherium individuals found into the "lagoa", but not to all. That means that the sequence of processes affecting the formation of this kind of fossil deposit is generally relatively complex.Key words: taphonomy, weathering, Megatheriidae, Brazil, Northeast region.RESUMO -São aqui apresentados os resultados de um estudo sobre a disposição espacial, análises das marcas e condições de preservação dos restos de preguiça-gigante (Eremotherium) descobertos na Lagoa Uri de Cima (Salgueiro, PE, Brasil). Os elementos esqueléticos de um mesmo indivíduo, um adulto, encontrados em uma área restrita (de cerca 8 m de diâmetro) e seu padrão tafonômico indica que o animal chegou à lagoa no estado de carcaça e seus ossos foram espalhados e danificados subsequentemente, sobretudo pelo pisoteamento de outros animais de grande porte quem transitaram no lugar. Esse modelo tafonômico pode também aplicar-se a alguns outros indivíduos de Eremotherium dessa lagoa, mas não a todos. Isso significa que a série de processos envolvidos na formação de um depósito fossilífero de lagoa é, em geral, relativamente complexa.Palavras-chave: tafonomia, intemperismo, Megatheriidae, Brasil, região Nordeste.

Lagoa do Quari (São Raimundo Nonato, Piauí): Palaeoenvironment and wetland archaeology in Northeastern Brazil

“…In addition, the alteration due to the atmospheric agents ('weathering', according to Behrensmeyer, 1978) was negligible. Some types of natural traces, like cracks and fractures, are present on the surface of bones, especially impact marks (Figure ; for details on traces of this type, see Valli, 2001, Valli & Mützenberg, 2016a). They can be the result of impacts with other bones or, most probably, with the quartz and gneiss cobbles of the deposit.…”

“…From the seventies onward, some pioneering palaeontologists, such as Rolim (1971, 1974) and C. de Paula Couto (1980), developed an interest in these sites. The lagoas, cacimbas or tanques (i.e., the local names of erosional pools developed on metamorphic rocks) have been reported as rich fossiliferous deposits of Pleistocene mammal megafauna (Araújo‐Júnior et al, 2017; Waldherr et al, 2017, 2019), and recently, they have also become the subject of many taphonomic studies (e.g., Araújo‐Júnior et al, 2015, 2017; Araújo‐Júnior, 2016; Asakura et al, 2014; Dantas et al, 2012, 2013, 2014; Dantas & Tasso, 2007; Faria et al, 2020; M. F. C. F. Santos et al, 2002; Valli & Mützenberg, 2016a, 2016b). These deposits have a widely homogeneous stratigraphy, consisting (from bottom to top) of a coarse‐grained bed with fossil megafauna, followed by an intermediate sand layer, sealed by fine‐grained deposits.…”