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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Taxonomy, biogeography and phylogeny of Cretaceous frog crabs (Crustacea, Decapoda, Brachyura) from the Neotropics

Luque, Javier 12 1900 (has links)
Le but du présent travail est d’apporter la preuve paléontologique mettant en évidence que le clade Raninoida était bien établi dans le Néotropique durant la période Crétacée, où il était représenté par les plus anciennes familles ou par quelques–uns des plus anciens membres des plus anciennes familles. Je décris des taxa raninoïdiens ou similaires, incluant Archaeochimaeridae n. fam. et Archaeochimaera macrophthalma n. gen. n. sp., du Cénomanien supérieur (~95 Ma.) de Colombie (Chapitre 3), Planocarcinus n. gen., Planocarcinus olssoni (Rathbun, 1937) n. comb. et Notopocorystes kerri n. sp., de l’Aptien supérieur (~115 Ma.) de Colombie (Luque et al., accepté) (Chapitre 2). Ces taxa nouveaux, plus la présence de Cenomanocarcinus vanstraeleni Stenzel, 1945, dans l’Albien supérieur de Colombie (Vega et al., 2010), et d’Araripecarcinus ferreirai Martins–Neto, 1987, dans l’Albien du Brésil (Luque et al., en cours) (Chapitre 4), représentent certains des plus anciens signalements de quatre des sept familles raninoïdiennes, au moins, connues à ce jour. La nouvelle famile Archaeochimaeridae se présente comme le groupe frère du clade Raninidae + clade Symethidae. Cependant, la combinaison unique de caractères primitifs, dérivés et homoplasiques est inégalable chez les Raninoida, et, en fait, chez les autres sections de crabes podotrèmes. Alors que les taxa raninoïdiens du Crétacé sont bien connus aux latitudes élevées, les signalements en Amérique du Sud tropicale sont rares et épars, avec pour résultat de considérables distorsions pour traiter des importantes questions biogéographiques et phylogénétiques. Sur la base de données taxonomiques, paléobiogéographiques et cladistiques, une ré–appréciation des toute premières distributions spatio–temporelle des “crabes grenouilles” est proposée, avec pour objet de contribuer à une plus large compréhension de la diversité, phylogénie et évolution des premiers brachyoures au cours des âges. / The aim of the present work is to present new paleontological evidence that depicts the clade Raninoida well established in the Neotropics during Cretaceous times, as represented by the oldest, or some of the oldest members of its earliest families. I describe raninoid and raninoidid–like taxa including Archaeochimaeridae n. fam., and Archaeochimaera macrophthalma n. gen. n. sp., from the upper Cenomanian (~95 Ma.) of Boyacá, Planocarcinus n. gen., Planocarcinus olssoni (Rathbun, 1937) n. comb., and Notopocorystes kerri n. sp., from the upper Aptian (~115 Ma.) of Santander. These newly described taxa, plus the occurrence of Cenomanocarcinus vanstraeleni Stenzel, 1945, in the upper Albian of Boyacá (Vega et al., 2010), and Araripecarcinus ferreirai Martins–Neto, 1987, in the lower Albian of Brazil (Luque et al., in progress), represent the oldest records of, at least, four out of seven raninoidid families known to date. The new family Archaeochimaeridae, stands as the sister taxon to Raninidae + Symethidae clade. However, its unique combination of primitive, advanced, and homoplasic traits is matchless within Raninoida, and in fact, with the remaining podotreme sections. While Cretaceous raninoid taxa from higher latitudes are well known, records from the tropical South America are scarce and sparse, resulting in considerable biases when attempting to address major biogeographic and phylogenetic questions. Based on taxonomic, paleobiogeographic and cladistic information, some reconsideration of the early spatio–temporal distributions of frog crabs are proposed, with the aim of contributing to a broader understanding of the diversity, phylogeny, and evolution of early brachyuran crabs throughout time.
32

Conchostráceos permianos da bacia do Paraná : taxonomia, evolução, bioestratigrafia e paleobiogeografia /

Ferreira-Oliveira, Luis Gustavo. January 2007 (has links)
Orientador: Rosemarie Rohn Davies / Banca: Ana Luisa Brossi Garcia / Banca: Fresia Soledad Ricardi Torres Branco / Banca: Oscar Rösler / Banca: Thomas Rich Fairchild / Resumo: O trabalho apresenta uma revisão dos conchostráceos da Formação Rio do Rasto (Bacia do Paraná, Permiano) e discussões substanciadas, em parte, pelos resultados dos experimentos realizados com representantes viventes cultivados em aquários. Concluiu-se que diversas características das carapaças normalmente usadas para a classificação dos conchostráceos fósseis não são diagnósticas para a distinção de táxons porque variam de acordo com fatores tafonômicos, ecológicos e ontogenéticos. Os conchostráceos vivem em águas continentais, são extremamente esteno-halinos e, ao contrário de alguns paradigmas da literatura, não vivem obrigatoriamente em corpos d'água efêmeros, toleram a presença de peixes predadores em seu habitat e duas espécies do mesmo gênero num único corpo d'água. Tais observações coadunam com o registro litológico e paleontológico da parte inferior da Formação Rio do Rasto, depositada em condições lacustres. A parte superior, onde há mais fácies eólicas e evidências de aumento de aridez, apresenta diversidade maior de conchostráceos, incluindo Hemicycloleaia mitchelli, uma espécie que permite realizar correlações cronoestratigráficos com a Austrália e Rússia. Sua idade provavelmente é neotatariana (=wuchiapingiana). Outros táxons, como Monoleiolophus unicostatus, também foram considerados nas correlações, estimando-se que a Formação Rio do Rasto esteja compreendida no Permiano médio-superior. / Abstract: Conchostracans of the Rio do Rasto Formation (Paraná Basin, Permian) are revised and discussions based on experiments with living conchostracans are presented. One conclusion is that many carapace characteristics frequently used for classification change according to taphonomic, ecologic and ontogenetic factors. The conchostracans live in continental fresh waters and, on the contrary of some paradigms of the literature, the organisms are not restricted to ephemeral water bodies and tolerate the presence of predatory fishes and two species of one single genus. These observations combine well with the lithological and paleontological record of the lower Rio do Rasto Formation deposited under lacustrine conditions. The upper part, formed under more arid conditions, presents bigger conchostracan diversity and includes Hemicycloleaia mitchelli. This species may be used for wide correlations with Australia and Russia, and its age probably is Late Tatarian (= Wuchiapingian). Other taxa, as Monoleiolophus unicostatus, were also used for correlations and the age of the formation may be interpreted as mid to late Permian. / Doutor
33

Taxonomy, biogeography and phylogeny of Cretaceous frog crabs (Crustacea, Decapoda, Brachyura) from the Neotropics

Luque, Javier 12 1900 (has links)
Le but du présent travail est d’apporter la preuve paléontologique mettant en évidence que le clade Raninoida était bien établi dans le Néotropique durant la période Crétacée, où il était représenté par les plus anciennes familles ou par quelques–uns des plus anciens membres des plus anciennes familles. Je décris des taxa raninoïdiens ou similaires, incluant Archaeochimaeridae n. fam. et Archaeochimaera macrophthalma n. gen. n. sp., du Cénomanien supérieur (~95 Ma.) de Colombie (Chapitre 3), Planocarcinus n. gen., Planocarcinus olssoni (Rathbun, 1937) n. comb. et Notopocorystes kerri n. sp., de l’Aptien supérieur (~115 Ma.) de Colombie (Luque et al., accepté) (Chapitre 2). Ces taxa nouveaux, plus la présence de Cenomanocarcinus vanstraeleni Stenzel, 1945, dans l’Albien supérieur de Colombie (Vega et al., 2010), et d’Araripecarcinus ferreirai Martins–Neto, 1987, dans l’Albien du Brésil (Luque et al., en cours) (Chapitre 4), représentent certains des plus anciens signalements de quatre des sept familles raninoïdiennes, au moins, connues à ce jour. La nouvelle famile Archaeochimaeridae se présente comme le groupe frère du clade Raninidae + clade Symethidae. Cependant, la combinaison unique de caractères primitifs, dérivés et homoplasiques est inégalable chez les Raninoida, et, en fait, chez les autres sections de crabes podotrèmes. Alors que les taxa raninoïdiens du Crétacé sont bien connus aux latitudes élevées, les signalements en Amérique du Sud tropicale sont rares et épars, avec pour résultat de considérables distorsions pour traiter des importantes questions biogéographiques et phylogénétiques. Sur la base de données taxonomiques, paléobiogéographiques et cladistiques, une ré–appréciation des toute premières distributions spatio–temporelle des “crabes grenouilles” est proposée, avec pour objet de contribuer à une plus large compréhension de la diversité, phylogénie et évolution des premiers brachyoures au cours des âges. / The aim of the present work is to present new paleontological evidence that depicts the clade Raninoida well established in the Neotropics during Cretaceous times, as represented by the oldest, or some of the oldest members of its earliest families. I describe raninoid and raninoidid–like taxa including Archaeochimaeridae n. fam., and Archaeochimaera macrophthalma n. gen. n. sp., from the upper Cenomanian (~95 Ma.) of Boyacá, Planocarcinus n. gen., Planocarcinus olssoni (Rathbun, 1937) n. comb., and Notopocorystes kerri n. sp., from the upper Aptian (~115 Ma.) of Santander. These newly described taxa, plus the occurrence of Cenomanocarcinus vanstraeleni Stenzel, 1945, in the upper Albian of Boyacá (Vega et al., 2010), and Araripecarcinus ferreirai Martins–Neto, 1987, in the lower Albian of Brazil (Luque et al., in progress), represent the oldest records of, at least, four out of seven raninoidid families known to date. The new family Archaeochimaeridae, stands as the sister taxon to Raninidae + Symethidae clade. However, its unique combination of primitive, advanced, and homoplasic traits is matchless within Raninoida, and in fact, with the remaining podotreme sections. While Cretaceous raninoid taxa from higher latitudes are well known, records from the tropical South America are scarce and sparse, resulting in considerable biases when attempting to address major biogeographic and phylogenetic questions. Based on taxonomic, paleobiogeographic and cladistic information, some reconsideration of the early spatio–temporal distributions of frog crabs are proposed, with the aim of contributing to a broader understanding of the diversity, phylogeny, and evolution of early brachyuran crabs throughout time.
34

Megafauna cenozóica do Continente Americano : considerações sobre ecomorfologia, paleoecologia, evolução e paleobiogeografia

Oliveira, Alessandro Marques de January 2018 (has links)
Orientador: Prof. Dr. Charles Morphy D. Santos / Coorientadora: Profa. Dra. Mirian Liza Alves Foranceli Pacheco / Tese (doutorado) - Universidade Federal do ABC, Programa de Pós-Graduação em Evolução e Diversidade, Santo André, 2018. / A presente tese teve por objetivo contribuir para o conhecimento a respeito da megafauna do Cenozóico do continente Americano. O foco do trabalho foi o estudo da megafauna pleistocênica da América do Sul, para correlações paleobiogeográficas e paleoecológicas, e da superordem Xenarthra, para considerações sobre ecomorfologia. Para as análises ecomorfológicas, foi considerado um contexto geocronológico e geográfico mais amplo, incluindo nas análises espécimes tanto do Neógeno quanto do Quaternário da América do Sul e do Norte. Foram descritas novas ocorrências de fósseis de mamíferos de grande porte ¿ tais como preguiças gigantes, gliptodontes, gonfotérios, tigres-dente-de-sabre e ursídeos ¿ para o estado do Mato Grosso do Sul. As considerações paleobiogeográficas consitiram em uma tentativa de correlação da paleofauna do Pleistoceno da Serra da Bodoquena com outras regiões da América do Sul. Além disso, uma nova ocorrência de filhote fossilizado de Nothrotherium maquinense é reportada para o estado de São Paulo com posterior datação radiométrica e análise de isótopos de carbono. O segundo ponto abordado nesta tese incluiu estudos ecomorfológicos em Xenarthra fósseis e atuais com base no formato do úmero. Para este fim, foi aplicado o método de morfometria geométrica bidimensional e tridimensional. Os resultados obtidos mostram que a Serra da Bodoquena apresenta maior similaridade taxonômica com a Região Intertropical Brasileira, devendo, portanto, ser incluída neste contexto paleobiogeográfico. Também verificou-se a ocorrência de um segundo táxon de Nothrotheriinae e de Ursidae em território brasileiro, além de um terceiro táxon de Scelidotheriinae. Os resultados sobre N. maquinense no estado de São Paulo indicam que a espécie estava presente na região por volta dos 13 mil anos antes do presente, e que se alimentava de plantas C3, indicando a possibilidade da presença de ambientes mais úmidos na região. Do ponto de visto ecomorfológico, foi verificado que o úmero de Xenarthra é funcionalmente informativo, sendo possível distinguir indivíduos adaptados para modos de vida arborícolas, semiarborícolas, ambulatoriais e escavadores. Adicionalmente, foi contastado a influência do tamanho sobre o formato do úmero. / The present thesis aimed to contribute to the knowledge about the Cenozoic Megafauna from the American continent. The focus was on both the Pleistocene Megafauna from South America, regarding paleobiogeographical correlations, and on the superorder Xenarthra, regarding considerations on ecomorphology. A broader geochronological and geographic context was considered to the ecomorphological analyses, including both Neogene and Quaternary specimens from South America and North America. The paleobiogeographical considerations were an attempt to correlate the Pleistocene paleofauna from Serra da Bodoquena to other South American regions. In addition, new occurrences of large mammal fossils ¿ such as giant sloths, glyptodonts, gomphotheres, felines and ursines ¿ were described for the state of the Mato Grosso do Sul. Additionally, a new occurrence of fossil cub identified as Nothrotherium maquinense was reported to the state of São Paulo. Dating and stable isotopes analyses were conduced. The second point addressed in this thesis includes ecomorphological studies on extant and extinct Xenarthrans based on the humerus shape. For this purpose, the bidimensional and tridimensional geometric morphometrics method were applied. The results showed that the Serra da Bodoquena presents greater taxonomic similarity to Brazilian Intertropical Region. Therefore, Mato Grosso do Sul should be included in this paleobiogeographical context. Additionally, the occurrence of a second Nothrotheriinae and Ursidae taxa, and a third Scelidotheriinae taxa was reported to Brazilian territory. The results on N. maquinense point out that such species was present in the region around 13 kya and it fed on C3 plants. This fact indicates the possibility of the presence of wetter environments in that region during late Pleistocene. From the ecomorphological point of view, it was verified that the Xenarthra humerus is functionally informative, being possible to distinguish individuals adapted to arboreal, semiarboreal, ambulatory and digger habitus. The influence of size on the humerus shape has been verified as well.
35

Rotas migratórias de braquiópodes (família Leptocoeliidae & família Tropidoleptidae) das bordas devonianas das bacias do Paraná e Parnaíba /

Ribeiro, Victor Rodrigues January 2019 (has links)
Orientador: Renato Pirani Ghilardi / Resumo: A distribuição dos continentes no Devoniano era diferente do que temos atualmente. As bacias sedimentares que ocupavam as áreas próximas do Equador (​e.g. Parnaíba, Amazonas, Solimões) hospedavam ecossistemas com uma grande diversidade de espécies. Por outro lado, as bacias que ocupavam regiões de alta latitude, como Paraná, hospedavam uma fauna de águas mais frias. Esta fauna, formalmente nomeada como Fauna Malvinocáfrica, é composta por uma diversidade baixa de Gastrópodes, Moluscos, Trilobitas e Braquiópodes (​Australocoelia​, Australospirifer,​ ​Australostrophia,​ ​Iridistrophia,​ ​Meristelloides​, ​Derbyina,​ ​Lingula ​e Orbiculoidea)​.NaBaciadoParaná(Centro-Sulbrasileiro)afaunadevonianaestá retratada na Formação Ponta Grossa, já na Bacia do Parnaíba (Norte-Nordeste brasileiro) a fauna ocorre pontualmente, justamente devido às condições paleoambientais e climáticas. No Devoniano Médio, as bacias do Paraná e Parnaíba, em resposta a subida do nível do mar, passaram por um período de mistura faunística, justificada pela ocorrência de ​Tropidoleptus carinatus (espécie de mares equatoriais) no meio das faunas Malvinocáfricas da Bacia do Paraná. Com a finalidade de averiguar tais eventos de dispersão, foram levados em consideração os gêneros ​Tropidoleptus e ​Australocoelia,​ sendo um oriundo de mares quentes e outro de mares frios, respectivamente. Análises morfofuncionais dos exemplares, levantamentos bibliográficos e trabalhos de campo indicaram que espécies de braquiópodes... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The distribution of continents in the Devonian was different from what we have today. The sedimentary basins that occupied the areas near Ecuador (e.g. Parnaíba, Amazonas, Solimões) hosted ecosystems with a big diversity of species. On the other hand, basins that occupied high latitude regions, such as Paraná Basin, hosted a colder water fauna. This fauna, formally named as Malvinokaffric Realm, is composed of a low diversity of Gastropods, Molluscs, Trilobites and Brachiopods (Australocoelia, Australospirifer, Australostrophia, Iridistrophia, Meristelloides, Derbyina, Lingula and Orbiculoidea). In the Paraná Basin (Center-South Brazil) the Devonian fauna is portrayed in the Ponta Grossa Formation, while in the Parnaíba Basin (North-Northeast Brazil) the fauna occurs punctually, precisely due to paleoenvironmental and climatic conditions. In the Middle Devonian, the Paraná and Parnaíba basins, in response to sea level rise, underwent a period of faunal mixing, justified by the occurrence of Tropidoleptus carinatus (species from equatorial seas) in the middle of the Malvinokaffric faunas of the Paraná Basin. In order to investigate such dispersal events, the genera Tropidoleptus and Australocoelia were taken into consideration, one from warm seas and one from cold seas, respectively. Morphofunctional analyzes of the specimens, bibliographic surveys and fieldwork indicated that species of equatorial brachiopods did not enter the Paraná Basin, but were restricted to the temperat... (Complete abstract click electronic access below) / Mestre
36

Nanofósseis calcários do Campaniano e Maastrichtiano no Atlântico Sul: bioestratigrafia, paleoceanografia e paleobiogeografia

Guerra, Rodrigo do Monte 19 January 2016 (has links)
Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-09-21T15:45:10Z No. of bitstreams: 1 Rodrigo do Monte Guerra_.pdf: 12842392 bytes, checksum: b6db9de51a65dd59c144edac22f16cab (MD5) / Made available in DSpace on 2016-09-21T15:45:10Z (GMT). No. of bitstreams: 1 Rodrigo do Monte Guerra_.pdf: 12842392 bytes, checksum: b6db9de51a65dd59c144edac22f16cab (MD5) Previous issue date: 2016-01-19 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Milton Valente / O final do período Cretáceo é caracterizado por uma gradual transição climática de escala global, fator que modificou a composição das assembleias de nanofósseis calcários e por conta disso vem causando problemas nas interpretações bioestratigráficas entre diferentes faixas latitudinais. Apesar de possuir alguns estudos realizados principalmente entre as décadas de 1980 e 1990, existe uma carência na avaliação do Atlântico Sul como um todo. Desta forma, este estudo objetiva descrever as assembleias de nanofósseis calcários comuns em cada faixa latitudinal e testar o sincronismo dos principais bioeventos. Foram analisadas 649 amostras provenientes de doze seções testemunhadas pelos projetos Deep Sea Drilling Project (DSDP) e Ocean Drilling Program (ODP) nas proximidades da margem brasileira e africana, além de um afloramento na Península Antártica. O estudo taxonômico possibilitou a identificação de 197 espécies de nanofósseis calcários do Campaniano e Maastrichtiano. Através do uso conjunto da bioestratigrafia e magnetoestratigrafia, foram reconhecidos diacronismos em eventos de primeira e última ocorrência de espécies do Campaniano superior e Maastrichtiano superior. Este diacronismo está relacionado a migrações de espécies entre baixas e médias latitudes, decorrentes de mudanças na circulação oceânica e temperatura das águas superficiais. Com base na variação latitudinal das assembleias de nanofósseis calcários, um detalhado estudo bioestratigráfico possibilitou a divisão de três zoneamentos para o Atlântico Sul (baixas, médias e altas latitudes). Além disso, foram definidos os padrões de distribuição de diversas espécies, mostrando uma clara divisão paleobiogeográfica entre espécies que ocorrem somente em latitudes altas e outras limitadas a latitudes médias a baixas. Este padrão possivelmente foi controlado por variações na temperatura das massas de água superficiais. Outras espécies possuem sua distribuição variada em todas as faixas latitudinais, tendo sua distribuição relacionada provavelmente à disponibilidade de nutrientes. / The Late Cretaceous period is characterized by global climatic transition that influenced calcareous nannofossil assemblages posing a challenge for biostratigraphic interpretation between different latitudinal degrees. There are a few studies on South Atlantic calcareous nannofossils from 1980 and 1990 decades, but none of them evaluate the South Atlantic as a whole. Therefore, this study aims to describe the calcareous nannofossils assemblages in each latitudinal zone and test the bioevents synchroneity. It were selected 649 samples from twelve cored sections coming from DSDP (Deep Sea Drilling Project) e ODP (Ocean Drilling Program) close to the Brazilian and African margins, in addition to an outcrop in the Antarctic Peninsula. The taxonomic study allowed the identification of 197 calcareous nannofossils species from the Campanian and Maastrichtian. Using the correlation between the biostratigraphical data and magnetostratigraphy, it was possible to identify diachronism in some bioevents of first and last occurrences during the late Campanian and late Maastrichtian. This diachronism is related to species migration between low and mid-latitudes, due to changes in the ocean circulation and surface water temperature. Based on the latitudinal variation in the calcareous nannofossils assemblages, a detailed biostratigraphic study enabled the South Atlantic division in three zonations (low, medium and high-latitudes). We also defined the distribution pattern of some species, indicating a clear paleobiogeographical division between high latitude species and some species limited to low and mid-latitudes. This pattern was possibly controlled by surface water temperature variation. Other species have a wide distribution across the latitudes probably related to nutrient availability.
37

CRETACEOUS CONFLUENCE IN THE COON CREEK FORMATION (MAASTRICHTIAN) OF MISSISSIPPI AND TENNESSEE, USA: TAPHONOMY AND SYSTEMATIC PALEONTOLOGY OF A DECAPOD KONSENTRAT-LAGERSTATTE

Kornecki, Krystyna Maria 31 October 2014 (has links)
No description available.
38

GIS Based Biogeography of Cincinnatian (Upper Ordovician) Brachiopods with Special Reference to Hebertella

Klingensmith, Brandon C. 03 October 2011 (has links)
No description available.
39

Paléoenvironnements et reconstitutions paléoclimatiques du Pléistocène moyen de Thaïlande et leur impact sur la biodiversité et la distribution des espèces : la contribution de la faune de vertébrés du gisement de Khok Sung (Province du Khorat) / Paleoenvironmental and paleoclimatic reconstructions of the Thai Middle Pleistocene and their impacts on the biodiversity and the species composition and distribution : the contribution of Khok Sung (Khorat province, Thailand) vertebrate community

Suraprasit, Kantapon 16 November 2015 (has links)
La sablière de Khok Sung, dans la province de Nakhon Ratchasima, qui a livré plus d'un millier de fossiles de mammifères et de reptiles (cranes, dents isolées et restes post-craniens), abrite la faune de vertébrés du Pléistocène la plus riche de Thaïlande. La faune mammalienne qui est décrite ici en détail, se compose d'au moins 18 espèces identifiées (12 genres), y compris un primate et des proboscidiens, rhinocéros, suidés, bovidés, cervidés et carnivores. Elle compte principalement des taxons encore représentés de nos jours, ainsi que quelques taxons globalement ou localement éteints. A partir des données paléomagnétiques et des comparaisons fauniques, l'âge de la faune de Khok Sung est estimé au Pléistocène Moyen tardif, vers 188000 ou 213000 ans. Par rapport aux autres faunes diversifiées du Pléistocène d'Asie du Sud Est, l'assemblage de Khok Sung est caractérisé par une association des taxons Stegodon-Ailuropoda, comparable en cela au site de Thum Wiman Nakin, ce qui supporte l'hypothèse selon laquelle le Nord Est de la Thaïlande était un corridor biogéographique appartenant à la route migratoire Sino-Malaise, entre la Chine du Sud et l'île de Java. L'analyse des isotopes stables du carbone à partir de l'émail des ongulés fossiles révèle la présence d'une partition de niches entre les méga-herbivores et au sein des cervidés. Les valeurs du d13C de l'émail suggèrent également que les ruminants ont consommé une grande quantité de plantes en C4, ce qui indique que les prairies à graminées étaient particulièrement répandues en Thaïlande à cette époque où les écosystèmes n'étaient pas encore soumis à l'influence anthropique. La mesure des isotopes stables de l'oxygène, obtenue par échantillonnage sérié de l'émail des dents de grands mammifères, et l'analyse du cénogramme de la localité de Khok Sung reflètent une importante variation saisonnière des précipitations et de la température, associée à des conditions climatiques relativement humides. / The Khok Sung sand pit, Nakhon Ratchasima province, has yielded the richest Pleistocene vertebrate fauna of Thailand, where more than a thousand fossil mammals and reptiles (skulls, isolated teeth, and postcranial remains) were recovered. The mammalian fauna, which is described in details hereby, consists of at least 18 identified species (12 genera), including a primate, proboscideans, rhinoceroses, suids, bovids, cervids, and carnivores, which are characterized by mostly extant elements associated to some completely and locally extinct taxa. The age of the Khok Sung fauna is tentatively attributed to the late Middle Pleistocene as either 188 or 213 ka, based on the paleomagnetic data and on the faunal comparisons. The Khok Sung mammal assemblage yields the Stegodon-Ailuropoda faunal association, most similar in composition to that of Thum Wiman Nakin, supporting the hypothesis that northeastern Thailand was a biogeographic gateway of the Sino-Malayan migration route from South China to Java. An analysis of stable carbon isotopes extracted from the tooth enamel of fossil ungulates reveals evidence of niche partitioning among megaherbivores and within cervids. The enamel carbonate d13C values also suggest a considerable amount of C4 plants in the dietary use of ruminants, indicating that grasslands had significantly expanded in Thailand at that time during which anthropic impacts on the ecosystems were absent. The stable oxygen isotope results, obtained from the serial sampling of large mammal enamel, combined with the cenogram analysis reflect significant seasonal variation in precipitations and temperature for Khok Sung, associated to a relatively humid climate.
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Evolution morphométrique et biogéographie des léporidés dans les environnements méditerranéens au Pléistocène : implications socio-économiques pour les sociétés humaines / Morphometric evolution and biogeography of leporids in Mediterranean environments during the Pleistocene : socio-economic implications for human societies

Pelletier, Maxime 07 September 2018 (has links)
En Europe de l’Ouest, de nombreuses espèces de léporidés sont endémiques, ce qui en fait de bons témoins de l’évolution des écosystèmes terrestres dans lesquelles ont évolué les sociétés humaines préhistoriques. Paradoxalement, leur variabilité morphologique est mal connue et la phylogénie établie aujourd’hui, discutable. Ce travail propose de renseigner la diversité morphométrique des lapins et des lièvres sur près de deux millions d’années d’évolution, à travers l’application d’études ostéométriques et en morphométrie géométrique. L’analyse de restes osseux et dentaires – de populations actuelles et de 73 séries fossiles provenant de régions périméditerranéennes couvrant le Pléistocène – permet de caractériser les adaptations des léporidés face aux changements environnementaux et leurs tendances évolutives. Cette étude propose une nouvelle phylogénie pour le lapin et présente les différentes phases de dispersion des taxons à l’échelle de l’Europe occidentale. Ainsi, plusieurs événements de type expansion des populations, recolonisation des territoires depuis des zones refuges et extinctions locales, sont mis en évidence en réponse aux changements climatiques globaux. Ces résultats permettent de discuter la présence de ces petits gibiers dans l’environnement et alimente le débat sur les relations entre ces espèces et les communautés humaines. Leur augmentation significative dans la diète des groupes humains à la fin du Paléolithique supérieur, ne semble pas seulement s’expliquer par des changements cognitifs, culturels ou économiques, mais coïncide davantage avec les variations biogéographiques de ces espèces. / Fossil remains of small mammals of the Leporidae family are abundant in numerous paleontological and archaeological deposits from the Quaternary. Many species are endemic to Western Europe, which makes them reliable markers of change in the ecosystems in which prehistoric human societies evolved. Paradoxically, morphological variability of leporids is still poorly understood and current phylogeny remains a subject of debate. This work focuses on the morphometric diversity of rabbits (Oryctolagus) and hares (Lepus) over nearly two million years of evolution. We applied osteometry and geometric morphometric analyzes to bone and dental remains of current populations and 73 fossil samples from perimediterranean regions (Spain, France, Italy, Portugal) during different moments of the Pleistocene. These data provide insights concerning Leporidae adaptations to environmental change as well as more general evolutionary trends. Here we propose a new phylogeny for the genus Oryctolagus and present different dispersion phases for Western Europe. Several population expansion events coupled with the recolonization of refuge areas and local extinctions are highlighted in response to global climate change. These results allow us to discuss the presence of these small game species in the environment and contribute to the debate concerning relations between leporids and human communities. Humans have regularly consumed leporids since at least the Middle Paleolithic. Their significant increase in the diet at the end of the Upper Paleolithic, however, cannot be explained solely by cognitive, cultural or economic changes but rather coincides with biogeographic variations of these species.

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