Thesis (M.A.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (May 20, 2007) Vita. Includes bibliographical references.

Made available in DSpace on 2016-01-13T13:27:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-04-17. Added 1 bitstream(s) on 2016-01-13T13:32:23Z : No. of bitstreams: 1 000855485.pdf: 7534024 bytes, checksum: 3199f68c4c86807d828a2b5a85013760 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Amphisbaenia é um importante grupo de amniotas reptilianos, providos de corpo cilíndrico e alongado, usualmente desprovidos de membros, com a exceção da Família Bipedidae, que apresentam os anteriores desenvolvidos. Esta anatomia facilita a vida fossorial. São alocados aos Squamata, por possuírem hemipênis, dente para romper e sair do ovo, cloaca transversal e tegumento coberto de escamas. Por assemelharem-se a lacertílios e ofídios, seu posicionamento filogenético tem sido amplamente discutido e sua ancestralidade é ainda controversa. São limitados às regiões subtropicais e tropicais, constituindo importante informação para abordagens paleoecológicas e paleobiogeográficas. Confeccionam profundos túneis compactando o solo, o que implica em grandes modificações morfológicas, tais como crânio robusto, formado por placas ósseas rígidas, e ligações interdigitais na região frontal, podendo ser sobrepostas, o que lhes confere maior resistência contra impactos na escavação. Sua anatomia é bastante convergente com aquela dos fósseis de lacertiformes mesozóicos, demonstrando um provável ancestral em comum com estes diápsidos. Um espécimen de Cryptolacerta, oriundo da Alemanha, compartilha características com Amphisbaenia. Entretanto sua filogenia ainda é incerta. De todo modo, junto com Sineoamphisbaena, pode indicar características convergentes entre lagartos laurasianos, possivelmente com aqueles que originaram Amphisbaenia. Os fósseis de anfisbênios são geograficamente restritos, predominantemente encontrados nos Estados Unidos, em quantidade relativamente escassa. A maior parte está relacionada à Família Rhineuridae, que poderia ser considerada primitiva. No entanto Bipedidae, um grupo recente, também é considerado como primitivo, devido à presença de cintura escapular e membros anteriores. Entretanto não há registros fósseis seguros, pois até então não foram encontrados restos fossilizados.. / Amphisbaenia is an important group of reptilian amniotes, provided with cylindrical and elongated body, usually limbless, with the exception of the Family Bipedidae, which presents limbs. This anatomy facilitates fossorial life. They are allocated to Squamata, by having hemipenis, tooth to break the egg, cross cloacal vent and integument covered with scales. Resembling lacertilians and snakes, their phylogenetic position has been widely discussed and their ancestry is still controversial. They are limited to subtropical and tropical regions, providing important paleoecological and paleobiogeographical informations to the group. They cave deep tunnels, compacting soil, which implies major morphological changes, such as robust skull bones, with rigid plates, and strong osteological connections in the frontal region, with superimposed bones, giving them greater resistance to impacts during excavation. Their anatomy is quite convergent with Mesozoic lacertiform fossils, showing a probable common ancestor with these diapsids. A specimen of VIII Cryptolacerta, from Germany, shares features with Amphisbaenia. However its phylogeny is still uncertain. But Sineoamphisbaena may indicate convergent features between Laurasian lizards, possibly with those originated Amphisbaenia. The fossil records are geographically restricted, predominantly from USA, in relatively small quantity. Most are related to the Family Rhineuridae, which could be considered primitive. However the Family Bipedidae, a recent group, is classified also as primitive, due to the presence of shoulder girdle and forelimbs. But Bipedidae does not present fossils, because until now there are not fossilized remains assigned to them. Morphological convergence occurs in Rhineuridae, detailed in phylogenetic analyses, placing it as a apomorphic group. Anyway it is clear that the origin of Amphisbaenia remains obscure. There are not well preserved fossil materials before beginning of Eocene

Orientador: Reinaldo José Bertini / Banca: Maria Eliana Carvalho Navega Gonçalves / Banca: Silvia Regina Gobbo Rodrigues / Resumo: Amphisbaenia é um importante grupo de amniotas reptilianos, providos de corpo cilíndrico e alongado, usualmente desprovidos de membros, com a exceção da Família Bipedidae, que apresentam os anteriores desenvolvidos. Esta anatomia facilita a vida fossorial. São alocados aos Squamata, por possuírem hemipênis, dente para romper e sair do ovo, cloaca transversal e tegumento coberto de escamas. Por assemelharem-se a lacertílios e ofídios, seu posicionamento filogenético tem sido amplamente discutido e sua ancestralidade é ainda controversa. São limitados às regiões subtropicais e tropicais, constituindo importante informação para abordagens paleoecológicas e paleobiogeográficas. Confeccionam profundos túneis compactando o solo, o que implica em grandes modificações morfológicas, tais como crânio robusto, formado por placas ósseas rígidas, e ligações interdigitais na região frontal, podendo ser sobrepostas, o que lhes confere maior resistência contra impactos na escavação. Sua anatomia é bastante convergente com aquela dos fósseis de lacertiformes mesozóicos, demonstrando um provável ancestral em comum com estes diápsidos. Um espécimen de Cryptolacerta, oriundo da Alemanha, compartilha características com Amphisbaenia. Entretanto sua filogenia ainda é incerta. De todo modo, junto com Sineoamphisbaena, pode indicar características convergentes entre "lagartos" laurasianos, possivelmente com aqueles que originaram Amphisbaenia. Os fósseis de anfisbênios são geograficamente restritos, predominantemente encontrados nos Estados Unidos, em quantidade relativamente escassa. A maior parte está relacionada à Família Rhineuridae, que poderia ser considerada primitiva. No entanto Bipedidae, um grupo recente, também é considerado como primitivo, devido à presença de cintura escapular e membros anteriores. Entretanto não há registros fósseis seguros, pois até então não foram encontrados restos fossilizados.. / Abstract: Amphisbaenia is an important group of reptilian amniotes, provided with cylindrical and elongated body, usually limbless, with the exception of the Family Bipedidae, which presents limbs. This anatomy facilitates fossorial life. They are allocated to Squamata, by having hemipenis, tooth to break the egg, cross cloacal vent and integument covered with scales. Resembling lacertilians and snakes, their phylogenetic position has been widely discussed and their ancestry is still controversial. They are limited to subtropical and tropical regions, providing important paleoecological and paleobiogeographical informations to the group. They cave deep tunnels, compacting soil, which implies major morphological changes, such as robust skull bones, with rigid plates, and strong osteological connections in the frontal region, with superimposed bones, giving them greater resistance to impacts during excavation. Their anatomy is quite convergent with Mesozoic lacertiform fossils, showing a probable common ancestor with these diapsids. A specimen of VIII Cryptolacerta, from Germany, shares features with Amphisbaenia. However its phylogeny is still uncertain. But Sineoamphisbaena may indicate convergent features between Laurasian "lizards", possibly with those originated Amphisbaenia. The fossil records are geographically restricted, predominantly from USA, in relatively small quantity. Most are related to the Family Rhineuridae, which could be considered primitive. However the Family Bipedidae, a recent group, is classified also as primitive, due to the presence of shoulder girdle and forelimbs. But Bipedidae does not present fossils, because until now there are not fossilized remains assigned to them. Morphological convergence occurs in Rhineuridae, detailed in phylogenetic analyses, placing it as a apomorphic group. Anyway it is clear that the origin of Amphisbaenia remains obscure. There are not well preserved fossil materials before beginning of Eocene / Mestre

Cricetidae, which includes a wide range of mice and rats, is the second-most diverse and abundant family of mammals. Though presently distributed across the Americas and Eurasia and also known from many fossil sites in western North America, few records have been studied from the east prior to the Pleistocene. This study has identified seven species of cricetids from the Gray Fossil Site (GFS), an early Pliocene site located in the northeast corner of Tennessee well-known for preserving fossils of many large mammals. While a few studies had previously noted the occurrence of cricetids at GFS, this study provides a detailed description of the cricetid assemblage and helps expand our understanding of small mammals from this site. Specimens were examined under stereomicroscope and DinoLite digital microscope camera, allowing qualitative assessment of occlusal morphology and quantitative comparison to modern cricetids and published fossil records from across North America. The most common taxa at the site included the deer mouse Peromyscus, which is currently the most abundant and widely distributed mammal in North America, deer mouse-like Postcopemys, and the woodrat Neotoma, which is larger rat with high-crowned molars that still lives in the region today. Other less common ones, like Sigmodon, Repomys, and Neotomodon, are also present. While most of the GFS specimens can be categorized into known genera, distinctive morphological features suggest the presence of new species. This assemblage of cricetids differs from those found at contemporaneous sites, emphasizing the spatial and temporal uniqueness of GFS. The Pliocene cricetid taxa at GFS exhibit diverse body sizes and dietary preferences, providing insights into the paleoecology of the region. As a biodiversity hotspot in the Appalachian region today, GFS was likely an important habitat for cricetid evolution during the Pliocene.

Macrofossils from a Mesozoic fossil flora from Ellesmere Island, North West Territories are described and their affinities discussed, Several rarely occurring genera and species ore discussed in detail. The deposit in which they occur is dated using the known ranges of identified macro fossils and miospores, rand the results compared with those of other workers. The described flora is compared with floras of similar age in other parts of the world. / Thesis / Master of Science (MS)

published_or_final_version / Earth Sciences / Doctoral / Doctor of Philosophy

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