Isotopes are one of the best tools to reconstruct the paleoecology of extinct taxa, allowing us to evaluate their diet (through carbon; C 3 and C 4 plants), their niche breadth (B A ) and the environment in which they lived. In the present work we go deeper in the use of isotopes, and explore a mathematical mixing model with the stable isotopic composition of one (carbon) and two elements (carbon and oxygen) to evaluate (i) the relative contributions of three types of food resources (leaves, fruits and C 4 grass) for meso-and megaherbivores (body mass > 100 kg) that lived during the late Pleistocene in Sergipe, Brasil, and (ii) which of these herbivores (together with some faunivorous taxa) could be potential preys for Smilodon populator and Caiman latirostris. Finally, we reconstructed the paleoenvironment in which the vertebrate community of Sergipe lived and concluded that the environment of Sergipe was a closer and drier landscape than African savannah nowadays, at least between 27 ka to 11 ka.
A preparação de fósseis é uma tarefa minuciosa, visto que qualquer procedimento incorreto pode causar danos irremediáveis às peças. Alguns autores brasileiros desenvolveram técnicas de preparação que permitem separar os restos esqueletais da rocha que os envolvem. Grande parte dos trabalhos no preparo de fósseis de paleovertebrados, por exemplo, concentram sua tônica no preparo de ictiólitos, assim é preciso desenvolver metodologias próprias para os outros grupos de paleovertebrados. O material deste estudo foi descoberto submerso na caverna Poço Azul do Milú, Bahia. Dentre o material, foi encontrado um esqueleto de preguiça-gigante, Eremotherium laurillardi (Lund, 1842). Tal pesquisa consiste na descrição de uma metodologia de preparação do material supracitado. A fase inicial deu-se com limpeza e estabilização do fóssil, que passou por dois banhos de acetato de polivinila, diluído em água. Após a secagem do material, iniciou-se a restauração das peças desarticuladas. Para isso foi utilizado acetato de polivinila, adesivo de cianoacrilato, gesso e estilete. Devido a seu peso e por ser um material mais fácil de partir-se, o gesso foi substituído pelo poliuretano para a confecção das camas de acomodação. Com as peças preparadas e acomodadas foi possível manuseá-las com maior segurança. Visto que o processo de fossilização do mesmo se deu em ambiente aquático ainda em atividade, o material fóssil apresenta-se melhor preservado em seus detalhes morfológicos. O que foge ao padrão dos achados de Eremotherium laurillardi, todos encontrados em ambientes já secos, sofrendo assim interferência maior do meio cárstico.
26Isotopes are one of the best tools to reconstruct the Paleoecology of extinct taxa, 27 yielding insights about their diet (through carbon; C 3 and C 4 plants), niche breadth (B A ) 28 and the environment in which they lived. In the present work we go deeper in the use of 29 isotopes and explore a mathematical mixing model with the stable isotopes of two 30 elements (carbon and oxygen) to (1) suggest the relative contribution of four types of 31 food resources (leaves, fruits, roots and C 4 grass) for meso-and megaherbivores (weight 32 > 100 kg) that lived in the Late Pleistocene of Poço Redondo, Sergipe, Brasil, and (2) 33 evaluate which of these herbivores could be the potential prey for the carnivores 34 Smilodon populator and Caiman latirostris. To explore the intra/interspecific 35 competition of these fauna, we generate weight estimation, standardized niche breadth 36 (B A ) for the meso-megamammals from Sergipe and compare with data from the meso-37 megaherbivores from Africa, concluding that Eremotherium laurillardi and Toxodon 38 platensis were the best resource competitors in the Late Pleistocene of Sergipe, and 39 reinforcing their importance as key species in this extinct community. Finally, we 40 reconstructed the paleoenvironment in which the vertebrate community of Sergipe 41 lived, estimating Mean Annual Temperature (ºC), Mean Annual Precipitation, Biomass 42 and Energy Expendidure, noting that environments in the Late Pleistocene of Sergipe 43were similar to those of Africa nowadays, but hotter and with more energy expenditure 44 for these meso-megamammals. 45 46 47 48 65 Most researchers use carbon and nitrogen isotopic data, extracting these data from 66 collagen. However, in tropical regions these proteins are difficult to be preserved, 67 leaving only the possibility to use carbon and oxygen isotopic data extracted from 68 hydroxyapatite. This mineral usually survives much better than the organic fractions of 69 collagen (Cherkinsky, 2009), being in tropical regions the best option to recover diet 70 information from extinct species. 71 The isotopic composition of hydroxyapatite can be preserved with minimal or no 72 significant diagenetic alteration. Hydroxyapatite carbonate and phosphate in bone and 73 dentin are more susceptible to diagenetic overprinting than enamel (Bocherens et al., 74 1996), for example. 75 Substitutions are mainly in the phosphate position and are most likely in the 76 hydroxyl position. The absorbed carbonates are more labile, but substitute ones are 77 structural carbonates, and, thus, contribute to saving the original isotopic composition 78 (Cherkinsky, 2009). 79 Thus, the main aims of this paper were to use mathematical mixing models using 80 carbon and oxygen isotopic (extracted from hydroxyapatite) data from fossil 81 vertebrates: (i) to infer four types of resources for herbivores (leaf, fruit, root and C 4 82 grass); (ii) to suggest, among the herbivorous mammals from Sergipe, Brazil, which 83 contributed to the isotopic diet of predators such as Smilodon...
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