Evidence for Metabolic Diversity in Meso-Neoproterozoic Stromatolites (Vazante Group, Brazil)

Deciphering the evolution of ecological interactions among the metabolic types during the early diversification of life on Earth is crucial for our understanding of the ancient biosphere. The stromatolites from the genus Conophyton cylindricus represent a datum for the Proterozoic (Meso to Neoproterozoic) on Earth. Their typical conical shape has been considered a result of a competition between microorganisms for space, light and nutrients. Well-preserved records of this genus from the Paleontological Site of Cabeludo , Vazante Group, São Francisco Craton (Southern Brazil) present in situ fossilized biofilms, containing preserved carbonaceous matter. Petrographic and geochemical analyses revealed an alternation between mineral laminae (light grey laminae) and fossilized biofilms (dark grey laminae). The dark grey laminae comprise three different biofilms recording a stratified microstructure of microbial communities. These three biofilms composing the dark grey laminae tend to be organized in a specific pattern that repeats through the stromatolite vertical section. Iron and manganese are distributed differently along the dark and light grey laminae; X-ray absorption and luminescence data showed possible different areas with authigenic iron and iron provided from diagenetic infiltration. Cryptocrystalline apatite in the lowermost biofilms in each dark grey laminae may suggest past metabolic activity of sulfide-oxidizing bacteria. These findings suggest that the microorganisms reached a complex metabolic diversification in order to maintain an equilibrium situation between the three different biofilms along the vertical section of the structures, thus benefiting the whole microbial community. This means that the stromatolites from the Conophyton genus may have formed as a result of a greater complexity of interactions between microorganisms, and not only from competition between photosynthesizers

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Perante a escassez dos estudos sobre Corumbella wemeri e a relevancia destes organismos para a cornpreensao de eventos biol6gicos e geol6gicos que ocorreram na transicao Ediacarano/Cambriano, uma reconstituicao morfol6gica , seguida de analise sistematica deste f6ssil, bem como as irnplicacoes paleoecol6gicas e tafon6micas das ocorrencias de C. wemeri, na Formacao Tamengo (Grupo Corurnba), Ediacarano, Mato Grosso do Sui, foram aqui desenvolvidas. Isto posto, os objetivos desta tese foram: a) revisar os especimes de C. wemeri, da Formacao Tamengo, Grupo Corurnba, a partir de amostras provenientes das pedreiras Saladeiro, Laginha, e do Ecoparque Cacimba da Saude, na reqiao de Corurnba, MS; b) reexaminar dos atributos e dos termos morfol6gicos, utilizados na literatura, para 0 estudo sistematico de C. wemeri; c) realizar uma analise tafon6mica basica, para a deterrninacao dos atributos morfol6gicos que pudessem alterar as interpretacoes taxon6micas; d) verificar a existencia de variacao na cornposicao taxon6mica de C. wemeri, da Formacao Tamengo; e) estabelecer caracteristicas paleoecol6gicas em C. wemeri; f) investigar evidencias morfol6gicas e paleoecol6gicas utilizadas na discussao das relacoes filoqeneticas de C. wemeri, entre os rnetazoarios (Cnidaria) e os vendobiontes (Vendobionta); e, g) comparar as ocorrencias de Corumbella da Formacao Tamengo com outras correlatas, como por exemplo, as da Formacao Wood Canyon, Great Basin, EUA, e do Grupo Itapucumi, Paraguai, para estabelecimento e discussao de caracteristicas taxon6micas e paleobiol6gicas, bem como suas irnpllcacoes tafon6micas. Os dados apresentados e discutidos neste trabalho referem-se a analises morfol6gicas realizadas em 596 amostras de mao. 0 reexame dos atributos morfol6gicos por meio de analise tafon6mica basica revelou incongruencias com as interpretacoes taxon6micas originais. Alern disso, por meio de modelagem qeornefrica foi possivel reconstituir diversos aspectos da morfologia e da estrutura deste f6ssil. Nao foi verificada a divisao bipartite do corpo descrita por Hahn e outros. Todavia, foram confirmadas a septacao interna e a simetria tetrarradial da descricao inicial. Adicionalmente, 0 exame de especirnes preservados tridimensionalmente sugeriu que os organismos eram piramidais e nao cilindricos, conforme originalmente descrito. Com base nas analises morfol6gicas, ate entao realizadas, foi possivel, seguramente, atribuir este taxon ao Reino Metazoa, filo Cnidaria, e nao ao reino Vendobionta. Inserido na Classe Scyphozoa, Familia Corumbellidae, C. werneri compartilha caracteristicas tanto com coronados quanto com conularios, sendo maior 0 nurnero de caracteristicas compartilhadas com este ultimo grupo. As cornparacoes com os exemplares da Formacao Wood Canyon, Great Basin, EUA, e do Grupo Itapucumi, Paraguai revelaram que estes se tratam da mesma especie, C. werneri. Contudo, apenas nos especirnes do Grupo Corurnba foram constatados importantes aspectos paleoecol6gicos, tais como brotamentos. Adicionalmente, foram obtidos dados a respeito da cornposicao quimica da carapace, sendo esta considerada orqanica ou fracamente mineralizada. Os resultados obtidos neste estudo vieram somar evidencias e dados fundamentais ao conhecimento e as interprertações sobre a origem e evolução dos animais no limite Ediacarano/Cambriano.Given the scarcity of studies on Corumbella werneri and the relevance of these organisms for the understanding of biological and geological events that occurred in the Ediacaran/Cambrian limit, a morphological reconstitution, followed by systematic analysis of this fossil, as well as the taphonomic and paleoecological implications of the occurrence of C . werneri in Tamengo Formation (Corurnba Group), Ediacaran, Mato Grosso do Sui, were developed here. In this thesis we aim to answer the following objectives: a) review of the specimens of C. werneri, Tamengo Formation, Corurnba Group, from samples collected at Laginha and Saladeiro quarries, and also at the Ecoparque Cacimba da Saude, Corurnba region, MS; b) review of the attributes and morphological terms used in the literature for the systematic study of C. werneri; c) basic taphonomic analysis for determination of the morphological attributes which can change taxonomic interpretations; d) investigation of existence of the variation in taxonomic composition in specimens of C. werneri, Tamengo Formation; e) establishment of paleoecological features in C. wemeri; f) observation of morphological and paleoecological evidence used in the discussion of the phylogenetic relationships between C. werneri, metazoan (Cnidaria) and vendobiontes (Vendobionta) and ; g) comparing the occurrences of Corumbella in Tamengo Formation with other related, e.g. the Wood Canyon Formation, Great Basin, USA, and Itapucumi Group, Paraguay, to discuss and to establish taxonomic characteristics, as well as theis paleobiological and taphonomical implications. The data presented and discussed in this study refer to the morphological analysis performed on 596 hand samples. The review of the morphological attributes through basic taphonomic analysis revealed inconsistencies with the original taxonomic interpretations. Furthermore, by the means of geometric modelling it was possible to reconstitute various aspects of the morphology and structure of this fossil. There was no bipartite division of the body, as described by Hahn and others. However, we confirmed the internal septation and tetrarradial symmetry of the initial description. Additionally, examination of three-dimensionally preserved specimens suggested that the organisms were pyramidal and non-cylindrical, as originally described. Based on morphological analysis, hitherto carried out, we could certainly assign this taxon to Kingdom Metazoa, Phylum Cnidaria, and not to the Kingdom Vendobionta. Housed in the Class Scyphozoa, Family Corumbellidae, C. werneri shares features both with coronates and conulariids, with higher number of characteristics shared with the latter group. Comparisons with specimens of the Wood Canyon Formation, Great Basin , USA, and the Itapucumi Group, Paraguay showed that they are from the same species, Corumbela werneri. However, only in specimens from Corurnba Group were found important paleoecological aspects, such as budding and suggestive gregarious way of life. In adition, we still obtained some data with respect to chemical composition of carapace. It was considered organic or weakly mineralized. The results of this study were added to the evidence and fundamental data to the knowledge and interpretations on the origin and evolution of animals on the Ediacaran/Cambrian edge

Zooarchaeology of the archaeological sites Maracaju 1, MS e Santa Elina, MT

Vestígios arqueofaunísticos resgatados em sítios arqueológicos de Mato Grosso e Mato Grosso do Sul revelaram a existência pretérita de grupos humanos caçadores-coletores generalistas, nestes Estados. Inseridos neste contexto, estão os sítios arqueológicos Maracaju 1, MS e Santa Elina, MT, caracterizados por serem abrigos sob rocha, que apresentam painéis com inscrições rupestres, e por uma quantidade de remanescentes arqueofaunísticos, associados a outros vestígios da cultura material. Diante do exposto, o presente trabalho teve por objetivos (1) compreender, sob a perspectiva da arqueofauna, os padrões de subsistência das populações humanas pretéritas que ocuparam Maracaju 1, MS e Santa Elina, MT, dois abrigos em bioma de Cerrado; (2) delinear as atividades (específicas ou não) realizadas pelos grupos humanos que ocuparam estes abrigos; e, diante disso, (3) inferir a função destes abrigos para as populações pretéritas locais. Para tanto, estes registros zooarqueológicos foram estudados por meio de métodos e técnicas multidisciplinares (e.g. Taxonomia e Tafonomia experimental). Diante dos resultados deste trabalho, foi possível inferir que a caça e as atividades de subsistência, nas ocupações atribuídas aos caçadores-coletores, em Maracaju 1, ocorreram de modo sucessivo e, provavelmente, sazonal. Esta característica de ocupação fortaleceu a hipótese do elevado grau de mobilidade e das ocupações mais horizontalizadas na paisagem, característica desses grupos humanos. Do mesmo modo, a explicação mais parcimoniosa para o contexto zooarqueológico de Santa Elina, é a de que as ocupações humanas tiveram um caráter, provavelmente sazonal e ocorreram durante as alocações de recursos ligadas a outros eventos culturais, evidenciados pelos registros rupestres e pelos vestígios arqueológicos resgatados neste sítio.Archaeofaunistic remains rescued in archaeological sites from Mato Grosso and Mato Grosso do Sul have shown the existence of generalists past hunter-gatherers groups in these states. Embedded in this context, there are the archaeological sites Maracaju 1, MS and Santa Elina, MT, characterized by being rock shelters, with rock art, and a quantity of archaeofaunistic remains, along with other traces of material culture. Facing the above, this work aimed to (1) understand, from the perspective of archaeofauna, the subsistence patterns of the people who occupied Maracaju 1, and Santa Elina, two shelters in the Cerrado biome, (2) outlining the activities (specific or not) done by human groups who occupied these shelters, and face it, (3) deduce the function of these shelters for local people. To reach that, these zooarchaeological records were studied using multidisciplinary methods and techniques (e.g. Taxonomy and Experimental taphonomy). Facing these results, it was possible to infer that hunting and subsistence activities, in occupations attributed to hunters-gatherers in Maracaju 1, occurred in successive and probably seasonal context. This occupation characteristic has strengthened the hypothesis of the high degree of mobility and more horizontalised occupations in the landscape, characteristic of these human groups. Similarly, the most parsimonious explanation for the zooarchaeological context of Santa Elina, is that the human occupation, probably had a seasonal character and occurred during the resources allocation related to other cultural events, evidenced by the rock art and the archaeological remains rescued in this site

Paleometry: a brand new area in brazilian science

Paleometry is a promising research field that brings together different areas, such as physics and chemistry, applied to paleobiological issues. In spite of being recognized abroad, it is a new research field in Brazil. The most important characteristic is the application of mostly non-destructive techniques to the study of fossils. This work compiles some paleometrical applications to different geological contexts, such as the synthesis of hard skeleton in Corumbella werneri, geochemical aspects about fresh water bivalves from the Bauru Group and the exceptional preservation of arthropods from the Crato Member. Diffuse Reflectance Infrared (DRIFT) and Energy Dispersive X-ray Spectroscopy (EDX) were complementary to elucidate the types of skeletogenesys in Corumbella. In the case of the bivalves, DRIFT revealed to be important to elucidate aspects about death and fossilization. Among arthropods, morphological analysis with Scanning Electron Microscopy (SEM) associated with EDX was more profitable to understand fossilization process and paleoenvironmental implications.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Paleometry: a brand new area in brazilian science

Paleometry is a promising research field that brings together different areas, such as physics and chemistry, applied to paleobiological issues. In spite of being recognized abroad, it is a new research field in Brazil. The most important characteristic is the application of mostly non-destructive techniques to the study of fossils. This work compiles some paleometrical applications to different geological contexts, such as the synthesis of hard skeleton in Corumbella werneri, geochemical aspects about fresh water bivalves from the Bauru Group and the exceptional preservation of arthropods from the Crato Member. Diffuse Reflectance Infrared (DRIFT) and Energy Dispersive X-ray Spectroscopy (EDX) were complementary to elucidate the types of skeletogenesys in Corumbella. In the case of the bivalves, DRIFT revealed to be important to elucidate aspects about death and fossilization. Among arthropods, morphological analysis with Scanning Electron Microscopy (SEM) associated with EDX was more profitable to understand fossilization process and paleoenvironmental implications