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No description available.

Texte remanié de: Th.--Sci.--Université de Brest, 1987. / Bibliogr. p. 271-278. Index. Résumé en langues diverses.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 154-160). Also available via the Internet.

Apesar do grande número de estudosenvolvendo taxonomia esistemática de braquiópodes, poucos foramos estudos que utilizassema metodologia de análise cladística. Desta forma,no estudo aqui apresentado, foi feita uma análise cladística dos taxabasais da Ordem Spiriferida, comatenção especialà superfamília Delthyridoidea. Esta superfamília, Siluro-Devoniano, temcomointegrante o taxon Australospirifer, representante típico do Domínio Malvinocáfrico, e presente no Devoniano brasileiro. A análise cladística tambémtem por objetivo testar a hipótese filogenética apresentada por Lespèrance e Bizarro (1999) para a superfamília Delthyridoidea. Braquiópodes, bivalves, tentaculítideos e trilobitas, típicos representantes do Província Malvinocáfrica, foram descritos para o flanco norte da Formação Ponta Grossa (Eo-mesodevoniano), Estado de Goiás, Brasil, uma área compoucos estudos paleontológicos. Foi descrita uma nova espécie para o gênero Ptychopteria, e umnovo gênero e nova espécie de espiriferídeo, comafinidades filogenéticas ao gênero Australospirifer. A análise cladística foi realizada com enraizamento a posteriori no taxon Eospirifer.O cladograma semiestrito resultante, escolhido como proposta detrabalho, apresentou CI=0,40, RI=0,70, RC=0,30. Apesar da baixa resolução, este estudo aqui discutido apresenta uma acuidade maior emrelação ao anteriormente realizado por Lespèrance e Bizarro (1999), principalmente por conter um maior número de caracteres e taxa.Como resultado, pôde ser observado que alguns grupos tradicionalmente considerados basais emSpiriferida, como Delthyridoidea e Cyrtioidea não são considerados monofiléticos. Por outro lado Reticularioidea e Martinioidea (excluindo Tenellodermis) são confirmados comogrupos monofiléticos. Além disso, o gênero Australospiriferé considerado um metataxon, sendo basal emrelação a um grupo inteiro, que corresponde tanto a taxatípicos do Hemisfério Norte quanto ao taxonnovo aqui descrito. / Despite the large number of taxonomic studies on fossil brachiopods, few include cladistic analysis. This study is one of the first to apply thismethod to basal taxa amongs Spiriferida, with special attention to the superfamily Delthyridoidea. This superfamily, restricted to the Silurian and Devonian, includes the taxon Australospirifer, which is common in Devonian deposits of Brazil and representative of the Malvinocafric Realm. This analysis also tests the phylogenetichypothesis proposed by Lespèrance and Bizarro (1999) for the superfamily Delthyridoidea. Brachiopods, bivalves, tentaculitids and trilobites, typical elements of the Malvinocafric Realm,are describedfrom the Ponta Grossa Formation (Early to Middle Devonian) in the northern portion of the Parana Basin in the State of Goiás, Brazil, a region still poorly known paleontologically, especially for brachiopods, when compared to the southern portion of the basin. A new species ofthe genus Ptychopteria,and a new genus and species ofspiriferidhaving phylogenetic affinities with the genus Australospiriferare described. The cladistic analysis was carriedout with a posteriorirooting in the taxon Eospirifer. The resulting semistrict cladogram, the preferred working hypothesis, presented CI=0,40, RI=0,70 and RC=0,30. Despite its relatively low topological resolution, this cladogrampresents greater accuracy than that proposed by Lespèrance and Bizarro (1999), mainly because of the greater number of characters, and taxa utilized. As a result,some groups, traditionally considered as basal within the Spiriferida, such as Delthyridoidea and Cyrtioidea, can not be interpreted here as monophyletic. On the other hand, Reticularioidea and Martinioidea (excluding Tenellodermis) are confirmed as monophyletics groups. In addition, the genus Australospirifer is considered a metataxon, and basal not only to the group including typical Northern Hemisphere taxa but also to the new genus and species described here.

Apesar do grande número de estudosenvolvendo taxonomia esistemática de braquiópodes, poucos foramos estudos que utilizassema metodologia de análise cladística. Desta forma,no estudo aqui apresentado, foi feita uma análise cladística dos taxabasais da Ordem Spiriferida, comatenção especialà superfamília Delthyridoidea. Esta superfamília, Siluro-Devoniano, temcomointegrante o taxon Australospirifer, representante típico do Domínio Malvinocáfrico, e presente no Devoniano brasileiro. A análise cladística tambémtem por objetivo testar a hipótese filogenética apresentada por Lespèrance e Bizarro (1999) para a superfamília Delthyridoidea. Braquiópodes, bivalves, tentaculítideos e trilobitas, típicos representantes do Província Malvinocáfrica, foram descritos para o flanco norte da Formação Ponta Grossa (Eo-mesodevoniano), Estado de Goiás, Brasil, uma área compoucos estudos paleontológicos. Foi descrita uma nova espécie para o gênero Ptychopteria, e umnovo gênero e nova espécie de espiriferídeo, comafinidades filogenéticas ao gênero Australospirifer. A análise cladística foi realizada com enraizamento a posteriori no taxon Eospirifer.O cladograma semiestrito resultante, escolhido como proposta detrabalho, apresentou CI=0,40, RI=0,70, RC=0,30. Apesar da baixa resolução, este estudo aqui discutido apresenta uma acuidade maior emrelação ao anteriormente realizado por Lespèrance e Bizarro (1999), principalmente por conter um maior número de caracteres e taxa.Como resultado, pôde ser observado que alguns grupos tradicionalmente considerados basais emSpiriferida, como Delthyridoidea e Cyrtioidea não são considerados monofiléticos. Por outro lado Reticularioidea e Martinioidea (excluindo Tenellodermis) são confirmados comogrupos monofiléticos. Além disso, o gênero Australospiriferé considerado um metataxon, sendo basal emrelação a um grupo inteiro, que corresponde tanto a taxatípicos do Hemisfério Norte quanto ao taxonnovo aqui descrito. / Despite the large number of taxonomic studies on fossil brachiopods, few include cladistic analysis. This study is one of the first to apply thismethod to basal taxa amongs Spiriferida, with special attention to the superfamily Delthyridoidea. This superfamily, restricted to the Silurian and Devonian, includes the taxon Australospirifer, which is common in Devonian deposits of Brazil and representative of the Malvinocafric Realm. This analysis also tests the phylogenetichypothesis proposed by Lespèrance and Bizarro (1999) for the superfamily Delthyridoidea. Brachiopods, bivalves, tentaculitids and trilobites, typical elements of the Malvinocafric Realm,are describedfrom the Ponta Grossa Formation (Early to Middle Devonian) in the northern portion of the Parana Basin in the State of Goiás, Brazil, a region still poorly known paleontologically, especially for brachiopods, when compared to the southern portion of the basin. A new species ofthe genus Ptychopteria,and a new genus and species ofspiriferidhaving phylogenetic affinities with the genus Australospiriferare described. The cladistic analysis was carriedout with a posteriorirooting in the taxon Eospirifer. The resulting semistrict cladogram, the preferred working hypothesis, presented CI=0,40, RI=0,70 and RC=0,30. Despite its relatively low topological resolution, this cladogrampresents greater accuracy than that proposed by Lespèrance and Bizarro (1999), mainly because of the greater number of characters, and taxa utilized. As a result,some groups, traditionally considered as basal within the Spiriferida, such as Delthyridoidea and Cyrtioidea, can not be interpreted here as monophyletic. On the other hand, Reticularioidea and Martinioidea (excluding Tenellodermis) are confirmed as monophyletics groups. In addition, the genus Australospirifer is considered a metataxon, and basal not only to the group including typical Northern Hemisphere taxa but also to the new genus and species described here.

The Middle Devonian brachiopod, Mucrospirifer, was studied over most of its geographical and stratigraphical range in order to test the theory of punctuated equilibria. Punctuated equilibria holds that most evolution is concentrated in rapid speciation events and that the subsequent lifespan of a species is then characterized by approximate morphological stasis. Although many fossil lineages have been studied since the theory of punctuated equilibria was proposed, very few have included broad geographical coverage. To study a species adequately through time, the extent of its morphological variation in space must be known. Specimens of Mucrospirifer were collected from New York, Ontario, Michigan, Pennsylvania, Maryland, and West Virginia from sandstones, siltstones, mudstones, calcareous shales, and limestones spanning 5-7 million years of geological history. Although many species of Mucrospirifer have been proposed, the most recent taxonomic work reduced the number to two and found that the overall shape of the shell and the shape of the fold and sulcus were the best criteria to distinguish species of Mucrospirifer. These same two criteria were applied in this study. Overall shape was examined by Fourier analysis of the outline of each usable adult specimen employing a video digitizing system assembled for this project. Selection of harmonics that contribute most to the shape of Mucrospirifer was aided by stepwise discriminant analysis, and only these harmonics were used in subsequent statistical analyses. Shape differences among adult specimens cannot be attributed to allometry which was not significant when linear regression of log-transformed data for harmonic 0 (size) vs harmonic 2 (shape) was applied. Using cluster analysis, polar ordination, and principal component analysis extensive continuous morphological variation of Mucrospirifer was detected over its geographical range as well as within populations, so that only a single polytypic species, Mucrospirifer mucronatus, could be identified. Although no strong correlation between morphology and lithology was found over the entire study area, using linear regression an east-west trend of increasing roundness was identified in New York state. This trend may be due to an adaptation to water turbulence that decreases from the nearshore in the east to the offshore in the west or to sediment type which becomes finer grained going from east to west. Using principal component analysis and linear regression, no significant directional change in overall shape could be detected. Therefore, morphological stasis characterizes the 5-7 million-year history of Mucrospirifer mucronatus in the study area. These findings lend substantial support to the theory of punctuated equilibria. / Ph. D.