Dissertations / Theses: 'Brachiopoda'

1

Craig, Robert S. "Western Australian Late Cretaceous and Cenozoic brachiopoda." Thesis, Curtin University, 1999. http://hdl.handle.net/20.500.11937/2320.

Full text

Abstract:

The research reported in this thesis focuses on Late Cretaceous and Cenozoic fossil brachiopods of Western Australia. Although the work is primarily taxonomic, it also includes biodiversity, distribution and some aspects of ecology of the brachiopods described.The most recent information on the anatomy, physiology and ecology of brachiopods is summarised at the beginning of the thesis.Identification of brachiopods is determined primarily on internal morphological features as brachiopods tend to be homomorphic, many species looking externally the same. The morphological features used in the identification of the brachiopods described within the thesis are defined.The fossil material studied has come from four sedimentary basins in Western Australia. The Carnarvon Basin contains Late Cretaceous and Cenozoic fossil material. The Perth Basin also has Late Cretaceous and late Cenozoic brachiopods The Bremer and Eucla Basin have Cenozoic deposits. The stratigraphy of the deposits containing the brachiopods is described.Until this study commenced, eight species had been described from Western Australia. This thesis describes fifty eight species including thirty new species, one new family and two new genera.In preparing descriptions of the new species it become evident that many of the species from the Southern Hemisphere were quite different to those found in the Northern Hemisphere. Their closest affiliation was with genera and species described from the Antarctic Peninsula. Four genera and one species from the Late Cretaceous deposits of Western Australia are common to the Late Cretaceous deposits of the Antarctic Peninsula. In the examination of the Tertiary material from the Carnarvon Basin, it also became clear that there was a strong correlation with Tertiary material from the Antarctic Peninsula. At least four genera are common to both deposits. Six brachiopod genera from the Middle Miocene deposits of the South Shetland Islands Antarctica are common to New Zealand. Nine genera, identified from the La Meseta Formation, Seymour Island, Antarctic Peninsula, are also common to New Zealand. These genera are also found in Australia. This evidence has led to the proposal that in the Late Cretaceous there was a common shelf environment from the Antarctic Peninsula to the north-west coast of Western Australia. In this area, which formed the high latitude southern circum-Indo-Atlantic faunal province, brachiopods evolved different genera and species than those in the northern hemisphere. Many then dispersed into northern areas of the Indian, Atlantic and finally Pacific Oceans.When the material from the Middle to Late Eocene of the Bremer and Eucla Basin was examined, five genera were found to be common to the Early Tertiary of the Carnarvon Basin. When comparing the species from the south-western basins and those from the south- east it was evident that similar species occur in the Middle to Late Eocene of the Bremer, Eucla, St Vincent and Murray Basins. There are some fifteen species in common. Many of these species then occur in the Late Oligocene south-eastern basins near Victoria and Tasmania as the gap between the Australia mainland and Tasmania began to open. One species that occurs in the Late Eocene of Western Australia is also described from the Late Oligocene of New Zealand.In considering the distribution of the Cenozoic brachiopods, genera first appear in the north-west of Western Australia and they then appear in chronological order in the south-western basins and south-eastern basins of South Australia, then the south-eastern basins of Victoria and Tasmania and then New Zealand. By the Late Eocene, there was a shallow marine connection between the Bight and the Tasman Sea. By the Late Oligocene this had widened and Australia was finally totally separated from Antarctica.The Proto-Leeuwin Current was responsible for the distribution of the brachiopods from the north-west of Western Australia to the southern coast. Possible mechanisms for the distribution of genera to New Zealand include rafting and an extended larval stage.It has been suggested that brachiopods in Australia are distributed according to the substrate on which they settle rather than any other factor. Using the information on the distribution of brachiopods in Western Australia throughout the Cenozoic this hypothesis is examined. It is suggested that avoidance of light in the photic zone and food availability with competition with bivalves are more important factors than substrate conditions.

APA, Harvard, Vancouver, ISO, and other styles

2

Craig, Robert S. "Western Australian Late Cretaceous and Cenozoic brachiopoda." Curtin University of Technology, School of Applied Geology, 1999. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=12043.

Full text

Abstract:

The research reported in this thesis focuses on Late Cretaceous and Cenozoic fossil brachiopods of Western Australia. Although the work is primarily taxonomic, it also includes biodiversity, distribution and some aspects of ecology of the brachiopods described.The most recent information on the anatomy, physiology and ecology of brachiopods is summarised at the beginning of the thesis.Identification of brachiopods is determined primarily on internal morphological features as brachiopods tend to be homomorphic, many species looking externally the same. The morphological features used in the identification of the brachiopods described within the thesis are defined.The fossil material studied has come from four sedimentary basins in Western Australia. The Carnarvon Basin contains Late Cretaceous and Cenozoic fossil material. The Perth Basin also has Late Cretaceous and late Cenozoic brachiopods The Bremer and Eucla Basin have Cenozoic deposits. The stratigraphy of the deposits containing the brachiopods is described.Until this study commenced, eight species had been described from Western Australia. This thesis describes fifty eight species including thirty new species, one new family and two new genera.In preparing descriptions of the new species it become evident that many of the species from the Southern Hemisphere were quite different to those found in the Northern Hemisphere. Their closest affiliation was with genera and species described from the Antarctic Peninsula. Four genera and one species from the Late Cretaceous deposits of Western Australia are common to the Late Cretaceous deposits of the Antarctic Peninsula. In the examination of the Tertiary material from the Carnarvon Basin, it also became clear that there was a strong correlation with Tertiary material from the Antarctic Peninsula. At least four genera are common to both deposits. Six brachiopod ++
genera from the Middle Miocene deposits of the South Shetland Islands Antarctica are common to New Zealand. Nine genera, identified from the La Meseta Formation, Seymour Island, Antarctic Peninsula, are also common to New Zealand. These genera are also found in Australia. This evidence has led to the proposal that in the Late Cretaceous there was a common shelf environment from the Antarctic Peninsula to the north-west coast of Western Australia. In this area, which formed the high latitude southern circum-Indo-Atlantic faunal province, brachiopods evolved different genera and species than those in the northern hemisphere. Many then dispersed into northern areas of the Indian, Atlantic and finally Pacific Oceans.When the material from the Middle to Late Eocene of the Bremer and Eucla Basin was examined, five genera were found to be common to the Early Tertiary of the Carnarvon Basin. When comparing the species from the south-western basins and those from the south- east it was evident that similar species occur in the Middle to Late Eocene of the Bremer, Eucla, St Vincent and Murray Basins. There are some fifteen species in common. Many of these species then occur in the Late Oligocene south-eastern basins near Victoria and Tasmania as the gap between the Australia mainland and Tasmania began to open. One species that occurs in the Late Eocene of Western Australia is also described from the Late Oligocene of New Zealand.In considering the distribution of the Cenozoic brachiopods, genera first appear in the north-west of Western Australia and they then appear in chronological order in the south-western basins and south-eastern basins of South Australia, then the south-eastern basins of Victoria and Tasmania and then New Zealand. By the Late Eocene, there was a shallow marine connection between the Bight and the Tasman Sea. By the Late Oligocene this had widened and ++
Australia was finally totally separated from Antarctica.The Proto-Leeuwin Current was responsible for the distribution of the brachiopods from the north-west of Western Australia to the southern coast. Possible mechanisms for the distribution of genera to New Zealand include rafting and an extended larval stage.It has been suggested that brachiopods in Australia are distributed according to the substrate on which they settle rather than any other factor. Using the information on the distribution of brachiopods in Western Australia throughout the Cenozoic this hypothesis is examined. It is suggested that avoidance of light in the photic zone and food availability with competition with bivalves are more important factors than substrate conditions.

APA, Harvard, Vancouver, ISO, and other styles

3

Swisher, Robert E. "Paleobiogeographical and evolutionary analysis of Late Ordovician, C₅ sequence brachiopod species, with special reference to Rhynchonellid taxa." Ohio : Ohio University, 2009. http://www.ohiolink.edu/etd/view.cgi?ohiou1245445583.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Long, Sarah Louise. "Aspects of cementation in recent and fossil Brachiopoda." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246325.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Welch, Delpfine Ellen. "Geographical variation and evolution in the Middle Devonian brachiopod, Mucrospirifer." Diss., This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-07282008-134118/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Pérez-Huerta, Alberto. "Brachiopods and paleoecological studies in the Pennsylvanian of the Great Basin (U.S.A.) /." view abstract or download file of text, 2004. http://wwwlib.umi.com/cr/uoregon/fullcit?p3136420.

Full text

Abstract:

Thesis (Ph. D.)--University of Oregon, 2004.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 394-419). Also available for download via the World Wide Web; free to University of Oregon users.

APA, Harvard, Vancouver, ISO, and other styles

7

Walls, Bradley J. "Quantitative Paleobiogeography of Maysvillian (Late Ordovician) Brachiopod Species of the Cincinnati Arch: a Test of Niche Modeling Methods for Paleobiogeographic Reconstruction." Ohio : Ohio University, 2009. http://www.ohiolink.edu/etd/view.cgi?ohiou1243010764.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Mello, Luiz Henrique Cruz de. "Análise cladística dos Bouchardiinae Allan, 1940 (Brachiopoda, Terebratellidae): implicações sistemáticas e paleozoogeográficas." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/44/44136/tde-13112015-164901/.

Full text

Abstract:

Foi realizada a investigação cladística dos Bouchardiinae (Brachiopoda, Terebratellidae), braquiópodes comuns no registro fóssil cenozóico da Argentina, Uruguai, Antártica, Nova Zelândia e Austrália, bem como, atualmente, na plataforma brasileira. A história geológica do grupo remete ao limite Cretáceo/Terciário. O estudo teve como objetivo central demonstrar que a análise das feições morfológicas internas e externas de conchas fósseis e atuais de braquiópodes possibilita a realização de estudos cladísticos. Para atingir esse objetivo foram avaliadas as relações de parentesco e a sistemática dos Bouchardiinae (Família Terebratellidae), bem como o escopo de seus gêneros. A análise envolveu os gêneros Bouchardia, Bouchardiella, Neobouchardia e Malleia, tendo como grupo externo Adnatida, Aliquantula, Anakinetica, Australiarcula, Elderra, Magadina, Magadinella, Parakinetica, Pilkena, Pirothyris e Rhizothyris. A análise contou com 22 táxons (grupo interno e externo) e 43 caracteres. O cladograma (CI= 0,714; RI= 0889; RC= 0,635) escolhido como proposta de trabalho apresentou topologia bem resolvida, com dois clados bem distintos. Um deles, reúne todos os Bouchardiinae, tendo Malleia portlandica como táxon basal, o outro agrupa os Anakineticinae, incluindo Australiarcula artesiana. Entre os Bouchardiinae, a única indefinição ficou por conta das espécies Bouchardia rosea e Bouchardia transplatina, o que reforça a suspeita de serem sinônimos. Entre os táxons do grupo externo destaca-se a posição basal de Australiarcula artesiana. Os resultados obtidos permitiram considerar que: a) a análise morfológica interna e externa de conchas de braquiópodes fósseis e viventes fornece dados morfológicos adequados à análise cladística; b) existem 2 clados distintos no cladograma escolhido como hipótese de trabalho, um representativo dos Bouchardiinae e outro dos Anakineticinae, incluindo Australiarcula artesiana, o que esclarece, de momento, a dúvida quanto a posição desse gênero; c) a condição dos táxons enquanto gêneros válidos e distintos foi reavaliada e foi proposta a sinonímia entre Bouchardiella e Neobouchardia, em favor da primeira; d) Bouchardia rosea e Bouchardia transplatina não apresentaram diferenças morfológicas significativas e, somando-se a isso, sua posição na topologia obtida sugere sinonímia entre os táxons, em favor de Bouchardia rósea (Mawe), 1823; e) o monofiletismo dos Bouchardiinae foi corroborado; f) foram confirmadas as 3 sinapomorfias já sugeridas pela literatura, isto é, espessamento posterior, processo cardinal em forma de \'V\' e braquídio incompleto; g) a topologia obtida suporta a sugestão de que Bouchardia rosea e Anakinetica cumingi apresentam morfologia semelhante por compartilharem modos de vida similares e não por parentesco próximo; h) a proposta de classificação mais adequada para os Bouchardiinae parece combinar opiniões de RICHARDSON (1994) e BRUNTON(1996), tornando válida a Subfamília Bouchardiinae, composta por Bouchardia, Bouchardiella e Malleia; i) a despeito da falta do registro estratigráfico de parte da história evolutiva dos Bouchardiinae, foi identificada a evolução em paralelo de dois grupos, um deles, de duração mais curta e restrito à Austrália e Nova Zelândia, formado por Bouchardiella cretacea, Bouchardiella (Neobouchardia) minima e Malleia portlandica, e outro, formado por Bouchardiella patagonica, Bouchardiella jorgensis e as espécies de Bouchardia, persistindo até o Recente, tendo se desenvolvido entre a Península Antártica e a costa leste da América do Sul; j) além do padrão geral de migração das espécies de Bouchardia para o norte, foram identificados alguns passos intermediários nesse modelo, principalmente quanto à migração de Bouchardia da Terra do Fogo (Argentina) para a Península Antártica; assim, o modelo de \"contínua migração das espécies para o norte, sem retenção de suas localidades prévias\" estaria parcialmente descartado, não invalidando, contudo, o padrão geral de migração para o norte.
A cladistic investigation of Bouchardiinae (Brachiopoda, Terebratellidae) was carried out. These brachiopods are common in the Cenozoic fossil record of Argentina, Uruguay, Antarctica, New Zealand, Australia, as well as in the Brazilian shelf. The geological history of the group can be tracked back until de Cretaceous/Tertiary boundary. The main goal of present study was to verify the hypothesis that morphological analysis on internal/external features of extinct/extant brachiopod shells allow us to proceed a cladistics analysis for the group. In order to achieve this goal, the relationships and systematic of the Bouchardiinae (Family Terebratellidae) were evaluated, as well as the scope of their genera. The cladistics analysis involved the in-group taxa Bouchardia, Bouchardiella, Beobouchardia, Malleia, having Adnatida, Aliquantula, Anakinetica, Australiarcula, elderra, Magadina, Magadinella, Parakinetica, Pilkena, Pirothyris, Rhizothyris, as the out-group. A total of 22 taxa and 43 characters were evaluated. The cladogram used as work hypothesis (CI= 0,714; RI= 0,889; RC= 0,635) presented a well resolved topology with 2 distinct clades; one with all Bouchardiinae, being Malleia portlandica the basal taxon; the other presented all Anakineticinae, including Australiarcula artesiana. The only unresolved relationship was between Bouchardia rosea and Bouchardia transplatina, suggesting that both taxa are synonymous. Among the out-group taxa the basal position of Australiarcula artesiana is worthy to mention. The results allow us to consider that: a) the morphological analysis of internal/external features of extinct/extant brachiopod shells supply important morphological data for cladistics analysis; b) there are 2 distinct clades that are representative of the Bouchardiinae and Anakineticinae, the later including Australiarcula artersiana, bringing some new evidences on their systematic position; c) the status of the genera, while valid and distinct taxa was re-evaluated, and resulted on the proposition of the synonymy between Bouchardiella and Neobouchardia, favoring the former; d) Bouchardia rosea and Bouchardia transplatina did not share significant morphological differences to keep them as distinct taxa. Thus the synonymy in favor of Bouchardia rosea (Mawe), 1823 is proposed; e) the monophyletic status of Bouchardiinae was corroborated; f) 3 synapomorphies ever suggested by the literature were confirmed, as follow: posterior thickening of the shell, \"V\" shapped cardinal process, and incomplete brachidia; g) based on the topology the condition of Bouchardia rosea and Anakinetica cumingi as distinct taxa is reinforced. Thus, their morphological similarities are much more due to similar ecological pressures (or mode of life) than to their close relationships; h) the classification of bouchardiid brachiopods seems to combine the suggestions of RICHARDSON (1994) and BRUNTON (1996), validating the Subfamily Bouchardiinae, with Bouchardia, Bouchardiella, and Malleia; i) despite of the lack of stratigraphic record of part of bouchardiid history, the parallel evolution of 2 groups was identified; one presenting a short interval, restricted to Australia e New Zealand, and corresponding to Bouchardiella cretacea, Bouchardiella (Neobouchardia) minima e Malleia portlandica, and the other group corresponding to Bouchardiella patagonica, Bouchardiella jorgensis, and species of Bouchardia, with an almost continuous record since the Cretaceous. This group evolved around the Antarctic Peninsula and east coast of southern South America; j) in spite the general north migration pattern presented by species of Bouchardia, some intermediate steps could be recognized, specially the migration of Bouchardia towards the Tierra del Fuego coast (Argentina) and Antarctic Peninsula. Consequently, the previous pattern of continuous northward migration of bouchardiid species without the retention of previous locations is only partially supported by the current data.

APA, Harvard, Vancouver, ISO, and other styles

9

Saxén, Sara. "Linguliform Brachiopods from the Middle Cambrian ‘Thick’ Stephen Formation at Odaray Mountain, Canadian Rocky Mountains." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-256188.

Full text

Abstract:

The linguliform brachiopod fauna from the Stephen Formation have long been thought to be very species poor and only consist of a few genera, but new discoveries from lime-stone beds in the “thick” Stephen Formation shows that this is not the case. The species described herein, Kyrshabaktella cf. tatjanae and Ceratreta hansi sp. nov., are two new additions to described species and genera of the area.The specimens come from a 0.6 meters thick limestone bed, approximately 17 meter above the base of the formation in the Canadian Rocky Mountains, British Columbia, Yoho National Park a few kilometers SSE from Odaray Mountain. The specimens where retained from the rock by dissolution in diluted formic acid for a few days and later coated with a palladium-gold alloy and photographed under a Scanning Electron Microscope (SEM).In addition to the widen knowledge that these specimens of K. cf. tatjanae and C. hansi brings to the paleoecology of the area the two species also expands the knowledge of their families and genera. The coarse filae ornamentation on the exterior shell of K. cf. tatjanae requires the revision of the diagnosis of the family Kyrshabaktellidae and the discovery of the new species C. hansi expands the stratigraphic range of the genus Ceratreta to the middle Cambrian.
Detta arbete behandlar arterna Kyrshabaktella cf. tatjanae och Ceratreta hansi sp. nov. från den ’tjocka’ Stephenformationen. Tidigare har området ansetts vara väldigt art- och släktfattigt på linguliforma brachiopoder. Nya fynd av Caron m.fl. (2010, 2014) visar på att så inte är fallet, och de fynd som behandlas här styrker den bilden. Fynden kommer från ett kalkstenslager beläget ca 17 meter upp i sekvensen på den ’tjocka’ Stephenformationen. Lagret har visat sig vara väldigt rikt på fossil. Med hjälp av dessa exemplar av K. cf. tatjanae har diagnosen av familjen Kyrshabaktellidae kunnat ändras, från att inte ha haft några utsmyckningar alls på de vuxna skalen till att kunna ha bland annat grovt koncentriska ornament (s.k. filae). Detta arbete och dessa nya fynd ska sprida ytterligare ljus över området. Förhoppningen är att denna ska hjälpa till att ge ny kunskap om områdets paleoekologi samt arterna och släktenas geografiska utbredning.Fossilen har separerats från kalkstenen genom att låta stufferna dra i utspädd myrsyra några dagar, tills kalken är upplöst. Fossilen har belagts med en palladium-guld legering och fotograferats med hjälp av ett svepelektronmikroskop (SEM).Syftet med arbetet är att göra en taxonomisk beskrivning av nya exemplar av brachiopodfossil från Stephenformationen.

APA, Harvard, Vancouver, ISO, and other styles

10

Alexander, Mannelqvist. "Paleontology and Sedimentology of the Alum Shale Formation at Björnberget, Västerbotten County, Sweden." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-296696.

Full text

Abstract:

A new locality of the Alum Shale Formation at Björnberget, Västerbotten County, of the lower allochthon of the Caledonian front is described herein. Two new species of acrotretid brachiopods were found. Tingitanella vilhelminia n. sp. adds another species to the monospecific genus. T. vilhelminia also extend the genus distribution to Sweden. Anabolotreta furcatus n. sp. is the first member of the genus found in Sweden and extend the stratigraphic range to Stage 5 of Cambrian Series 3. It also exhibits an unusual bifurcating shell structure described for the first time herein. One trilobite was found at the locality, Acadoparadoxides torelli, indicating that the exposures at Björnberget belong to the upper Acadoparadoxides (Baltoparadoxides) oelandicus superzone. The fauna found is impoverished in comparison to the fauna that has been described from Jämtland and reflects the depositional environment on the deep outer shelf with low sediment input. The known exposure at Granberget, close to Björnberget, is described with respect to the paleontology and sedimentology of the section. The fauna at Granberget could be extended with two new species of agnostids, Hypagnostus lingula and Hypagnostus mammillatus, to a total of six taxa of trilobites. The depositional environment was periodically affected by storms, depositing limestone layers composed of skeletal material. The Alum shale does not exhibit these sedimentary structures and have probably lost the majority of the them during diagenesis.
En hitintills obeskriven lokal av Alunskifferformationen vid Björnberget, Västerbottens län, beskrivs här med fokus på paleontologi och sedimentologi. Två nya arter av brachiopoder (Acrotretida) upptäcktes. Tingitanella vilhelminia n. sp. utökar släktet med ytterligare en art och utökar även den geografiska distributionen av släktet till Sverige. Anabolotreta furcatus n. sp. är den första medlemmen av släktet som beskrivits från Sverige och utökar den stratigrafiska spännvidden till lägre mellersta Kambrium. A. furcatus har även en skalstruktur med förgrenande pelare som beskrivs för första gången. En trilobit upptäcktes vid lokalen, Acadoparadoxides torelli, vilket tyder på att exponeringarna vid Björnberget tillhör övre delen av superzonen Acadoparadoxides (Baltoparadoxides) oelandicus. Faunan är artfattig i jämförelse med vad som tidigare har beskrivits från Jämtland och reflekterar en depositionsmiljö på den yttre kontinentalsockeln med ett lågt inflöde av klastiska sediment. Den sedan tidigare kända lokalen vid Granberget, nära lokalen vid Björnberget, beskrivs häri med avseende på paleontologi och sedimentologi. Faunan vid Granberget kan utökas med två nya arter av agnostider, Hypagnostus lingula och Hypagnostus mammillatus, till att totalt innehålla sex arter av trilobiter. Depositionsmiljön påverkades periodvis av stormar som avsatte kalkstenslager bestående av skelettdelar. Alunskiffern har förlorat majoriteten av dessa strukturer under diagenes som annars återfinns i kalkstenskonkretionerna.

APA, Harvard, Vancouver, ISO, and other styles

11

Cerri, Cássio Angelo Dalcin. "Revisão sistemática dos Brachiopoda (Calciata), da Formação Ponta Grossa, Devoniano, Bacia do Paraná, Brasil." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/44/44141/tde-30032015-151753/.

Full text

Abstract:

Uma análise sistemática dos braquiópodes (Brachiopoda, Calciata) da Formação Ponta Grossa, Devoniano, Sub-bacia Apucarana, Estado do Paraná, Bacia do Paraná, Brasil, é apresentada. Os Brachiopoda (Calciata) da Formação Ponta Grossa, Bacia do Paraná, Estado do Paraná, Brasil, foram inicialmente estudados por John Mason Clarke em 1913 e, desde então, nunca foram o alvo de uma revisão sistemática apropriada. Estudos tafonômicos prévios sobre outros grupos da mesma localidade sugerem que muitas espécies descritas para ela podem corresponder a espécies tafonômicas. Os objetivos do presente trabalho foram: a- revisar a sistemática dos braquiópodes Calciata da Formação Ponta Grossa, Devoniano, a partir do estudo morfológico do material fóssil disponível; b- verificar a diversidade da fauna de braquiópodes Calciata dessa Formação, comparando a trabalhos da Formação Ponta Grossa do Estado do Mato Grosso; c- verificar se alguns caracteres morfológicos utilizados na diagnose de gêneros e espécies de braquiópodes Calciata da Formação Ponta Grossa, do Estado do Paraná, são susceptíveis a modificações tafonômicas, particularmente devido à compactação post-mortem e a esfoliação, conforme ocorre com outros grupos fósseis, tais como conulários e trilobitas. Os resultados mostraram que, das espécies previamente descritas, Australostrophia mesembria, Pleurochonetes falklandicus, Cryptonella baini e Australocoelia palmata são válidas e permanecem sem modificação; a espécie Coelospira (?) colona pôde ser somente identificada a nível genérico devido à falta de dados disponíveis nas amostras analisadas. Os gêneros Australospirifer, Schuchertella e Derbyina apresentaram problemas na identificação. Autralospirifer é considerado um gênero válido e possui cinco espécies descritas para a Formação Ponta Grossa, porém os caracteres diagnósticos que as diferem são passíveis de modificação tafonômica, fato evidenciado em exemplares analisados, além de apresentarem um grau de variação alto, o que impede a identificação dessas espécies. Duas espécies de Schuchertella são descritas para a Formação Ponta Grossa, gênero que sofreu uma revisão taxonômica, excluindo essas espécies da classificação genérica. Tais espécies poderiam pertencer ao gênero Floweria, porém a falta de dados nas amostras impede a validação desta hipótese. Derbyina é um gênero controverso, muito similar ao gênero Paranaia, os quais recentes revisões afirmam serem distintos. Devido à falta de dados no material examinado, especificamente o braquídio, não foi possível confirmar a distinção entre esses gêneros nem uma identificação específica. O presente trabalho fortaleceu a ideia de que a designação de novas espécies deve ser realizada perante a presença de diversos espécimes, para que o maior espectro possível de variações tafonômicas e morfológicas decorrentes do processo de fossilização seja identificado, com holótipos bem preservados, o que diminui a margem de erros. Portanto, é importante aliar a tafonomia com o estudo sistemático, a fim de identificar caracteres sujeitos à maior variação tafonômica.
A systematic analysis of the Brachiopoda (Calciata) from Ponta Grossa Formation, Devonian, Apucarana Sub-basin, Paraná Basin, Paraná State, Brazil, is presented. The Brachiopoda (Calciata) from Ponta Grossa Formation, Paraná Basin, Paraná State, Brazil, were initially studied by John Mason Clarke in 1913 and, since then, were not the object of proper systematic revision. Previous taphonomic studies about other groups from the same location suggest that many species described may correspond to taphonomic species. The objectives of this article were: a- to revise the systematic of the Brachiopoda (Calciata) of the Ponta Grossa Formation, Devonian, through morphological study of the available fossil material; b- to verify the diversity of Calciata brachiopods of this Formation, comparing it to works from the Ponta Grossa Formation in the State of Mato Grosso; c- to verify if any of the morphological characters used in the diagnosis of genera and species of Calciata brachiopods from Ponta Grossa Formation, Paraná State, are susceptible to taphonomic modification, particularly post-mortem compaction and exfoliation, as occurs in other fossil groups, like conulariids and trilobites. The results have shown that, of the species previously described, Australostrophia mesembria, Pleurochonetes falklandicus, Cryptonella baini and Australocoelia palmata are valid and remain unchanged; the species Coelospira (?) colona could only be identified up to a generic level due to lack of data on the samples analyzed. The genera Australospirifer, Schuchertella and Derbyina presented problems during their identification. Autralospirifer is considered a valid genus and possesses five described species for the Ponta Grossa x Formation, although the diagnostic characters that differentiate them are susceptible to taphonomic modification, fact evidenced in analyzed samples, with them also presenting high variability degree, which impedes the identification of those species. Two species of Schuchertella are described to the Ponta Grossa Formation, a genus that has undergone taxonomic revision, excluding those species from the generic classification. Those species may belong in the Floweria genus, but the lack of data on the samples makes impossible the validation of this hypothesis. Derbyina is a controversial genus, very similar to the genus Paranaia, which recent revisions claim to be different from each other. Due to the lack of data in the examined material, specifically the brachidium, it was not possible to confirm the distinction between these genera, as well as specific identification. The present work has strengthened the idea that the designation of new species must be made in face of a considerable number of samples, so that the largest spectrum of taphonomic and morphological variations resulting from the fossilization process is identified, which diminishes the error margin. Therefore, it is important to combine taphonomy with the systematic study, in order to identify characters which are subject to greater taphonomic variation.

APA, Harvard, Vancouver, ISO, and other styles

12

Torello, Fernanda de Freitas. "Tafonomia experimental do fóssil vivo Bouchardia rosea (Brachiopoda, Terebratellidae) e suas aplicações em paleontologia." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/44/44136/tde-11112015-151000/.

Full text

Abstract:

Em Tafonomia Experimental, o uso do tambor tafonômico simula condições operantes nos ambientes de alta energia (e.g., abrasão). Neste estudo foi empregado um tambor de aço inoxidável, com aletas internas, diâmetro de 15cm e velocidade de 60rpm. O tamanho amostral foi de 10 espécimes para cada experimento e réplicas. Os experimentos e réplicas foram avaliados estatisticamente, e investigaram a preservação diferencial e destruição após a morte de conchas calcíticas de braquiópodes viventes (Bouchardia rosea, Terebratellidae) e moluscos bivalves (Veneridae, Pectinidae, Mytilidae e Pinnidae), cujos restos são comuns no registro fóssil Fanerozóico. As conchas de Bouchardia rosea são importantes do ponto de vista tafonômico, pois apresentam características mineralógicas e estruturais semelhantes às conchas de alguns grupos de braquiópodes paleozóicos (e.g., rinchonelídeos e terebratulídeos), além de modo de vida comum aos membros desses grupos, neste intervalo de tempo. As observações efetuadas têm implicações no entendimento dos processos de destruição que operam sobre os bioclastos e que contruibuem para produzir tendenciamentos no registro fóssil (fonte primária de dados paleobiológicos e evolutivos). Foi observado que: a) a composição orgânica, mineralógica e forma das conchas de bivalves e braquiópodes não estão diretamente associadas ao comportamento de decaimento de massa, durante a abrasão, podendo fatores extrínsecos serem responsáveis pela perdadiferencial de massa; b) valvas dorsais e ventrais de Bouchardia rosea apresentam resultado de redução final de massa com valores muito próximos, apesar de possuírem comportamento de decaimento de massa distintos, levantando a suspeita de que a resistência à abrasão não é o principal fator que controla o tendenciamento observado em muitas concentrções fossilíferas, em favor de uma das valvas; c) valvas de Bouchardia rosea de tamanho pequeno (~1cm) apresentam comportamento distinto com relação ao decaimento de massa, quando comparadas às valvas médias (~1,4cm) e grandes (~1,8cm), que se comportam similarmente, possivelmente devido à diferença de densidade; d) valvas incrustadas, com bioerosão ou frescas não apresentam comportamento de decaimento de massa semelhantes, demonstrando que a presença de elementos incrustantes ou a atuação de organismos responsáveis pela bioerosão não necessariamente aumentam ou diminuem a resistência das valvas à abrasão. Os dados obtidos através dos experimentos realizados em laboratório, complementados por observações de campo poderão auxiliar na interpretação da história deposicional e na identificação de processos de mistura espacial e temporal em acumulações modernas ou concentrações fósseis dominadas por conchas de braquiópodes.
The taphonomic tumbling barrel, used in Experimental Taphonomy, simulate high energy conditions (e. g., abrasion) that operate in some environments. In this study, it was used a steel barrel, with internal shelves, 15 centimeters diameter, and 60rpm of velocity. Ten specimens were used as sample size for each experiment and replicates. All experiments were evaluated by statistical methods. The main goal of this study was the investigation of differential preservation and post-mortem destruction of calcitic brachiopod shells (Bouchardia rosea, Terebratellidae) and bivalve mollusks (Veneridae, Pectinidae, Mytilidae and Pinnidae). Bouchardia rosea shells are taphonomically important because their composition and microstructures that are similar within Paleozoic members of rhynchonellids and terebratuliids, as well as a free lying mode of life. The obtained results have implications in our understandings of decay processes that act over the bioclasts and contribute to the bias of the fossil record (the primary source of paleobiological and evolutionary data). The main obtained results are: a) the organic and mineralogical composition and the shell form would not represent the main factor associated to the mass decay behavior, being extrinsic factors probably responsible to the differential loss of mass; b) ventral and dorsal Bouchardia rosea valves present similar values for the mass decay, leading to the believe that the abrasion resistance is not the main factor controlling the bias between ventral and dorsal valves in the modern accumulation and fossil concentrations; c) small valves of Bouchardia rosa (~1 cm) have distinct behavior in decay of mass when compared to medium (~1.4cm) and large shells (~1,8cm), that have similar decay behavior, probably due to density differences; d) incrusted, bioeroded and fresh valves have different mass decay behavior. It probabily indicate that bioeroded and incrusted elements do not necessarily increase or decrease the valve abrasion resistance. By complementing the obtained laboratory results with field observations both the depositional history and the spatial and temporal resolution of a given brachiopod-rich fossil concentration will be better understood.

APA, Harvard, Vancouver, ISO, and other styles

13

Chen, Zhong Qiang, and mikewood@deakin edu au. "Late palaeozoic sequence stratigraphy and brachiopod faunas of the Tarim Basin, Northwest China." Deakin University. School of Ecology and Environment, 2001. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20050915.141146.

Full text

Abstract:

This thesis deals with the stratigraphy and brachiopod systematic palaeontology of the latest Devonian (Famennian) to Early Permian (Kungurian) sedimentary sequences of the Tarim Basin, NW China. Brachiopod faunas of latest Devonian and Carboniferous age have been published or currently in press in the course of the Ph.D candidature and are herein appendixed, while the Early Permian brachiopod faunas are systematically described in this thesis. The described Early Permian brachiopod faunas include 127 species, of which 29 are new and 12 indeterminate, and six new genera (subgenera) are proposed; Tarimella, Bmntonella, Marginifera (Arenaria), Marginifera (Nesiotia), Baliqliqia and Ustritskia. A new integrated brachiopod biostratigraphical zonation scheme is proposed, for the first time, for the latest Devonian-Early Permian sequences of the entire Tarim Basin on the basis of this study as well as previously published information (including the Candidate's own published papers). The scheme consists of twenty three brachiopod acm biozones, most of which replace previously proposed assemblage or assemblage zones. The age and distribution of these brachiopod zones within the Tarim Basin and their relationships with other important fossil groups are discussed. In terms of regional correlations and biostratigraphical affinities, the Late Devonian to Early Carboniferous brachiopod faunas of the Tarim Basin are closest to those from South China, while the Late Carboniferous faunas demonstrate strong similarities to coeval faunas from the Urals, central Asia, North China and South China. During the Asselian-Sakmarian, strong faunal links between the Tarim Basin and those of the Urals persisted, while at the same time links with central Asia, North China and South China weakened. On the other hand, during the Artinskian-Kungurian times, affinities of the Tarim faunas with the Urals/Russian Platform rapidly reduced, when those with peri-Gondwana (South Thailand, northern Tibet) and South China increased. Thirty lithofacies (or microfacies) types of four facies associations are recognised for the Late Devonian to early Permian sediments. Based on detailed lithostratigraphy, biostratigraphy and facies analysis, 23 third-order sequences belonging to four supcrsequences are identified for the Late Devonian to Early Permian successions, from which sea-level fluctuation curves are reconstructed. The sequence stratigraphical analysis reveals that four major regional regressions, each marking a distinct supersequence boundary, can be recognised; they correspond to the end-Serpukhovian, end-Moscovian, late Artinskian and end-Kungurian times, respectively. The development of these sequences is considered to have been formed and regulated by the interplay of both eustasy and tectonism. Using the system tract of a sequence as the mapping time unit, a succession of 47 palaeogeographical maps have been reconstructed through the Late Devonian to Early Permian. These maps reveal that the Tarim Basin was first immersed by southwest-directed (Recent geographical orientation) transgression in the late Famennian after the Caledonian Orogeny. Since then, the basin had maintained its geometry as a large, southwest-mouthed embayment until the late Moscovian when most areas were the uplifted above sea-level. The basin was flooded again in late Asselian-Artinskian times when a new transgression came from a large epicontinental sea lying to its northwest. Thereafter, marine deposition was restricted to local areas (southwestern and northwestern margins until the late Kungurian, while deposition of continental deposits prevailed and continued through the Middle and late Permian into the Triassic.

APA, Harvard, Vancouver, ISO, and other styles

14

Wang, Haizhou. "Origin and Lifestyles of early Brachiopods and other Lophotrochozoans : Insights from the Chengjiang and Guanshan Fossil-Lagerstätten." Doctoral thesis, Uppsala universitet, Paleobiologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-234843.

Full text

Abstract:

One of the great unsolved evolutionary questions concerns the origin and phylogeny of the major animal phyla that appeared in the fossil record more than 540 million years ago, during the Cambrian explosion. Although new molecular information has been very useful, we still have little understanding about the origin of most of the phyla of bilaterians living today. The richly diverse fossil remains from this critical early Cambrian interval are particularly well exposed in China, where exceptionally-preserved fossil lophotrochozoans including brachiopods are particularly abundant. In particular the exceptionally-preserved Cambrian lophophorates from the Chengjiang and Guanshan Lagerstätten have offered new sources of critical palaeobiological data that have been shown to be important for understanding the early ecology and evolution of lophotrochozoans. This thesis comprises a detailed study of new, abundant, exceptionally-preserved material of five lophotrochozoan species from the Chengjiang and Guanshan Lagerstätten. Kuangshanotreta malungensis from Chengjiang is the earliest known example of an attached acrotretoid brachiopod representing the oldest evidence about the palaeoecology of the diverse yet, enigmatic acrotretoid linguliform stock that comprises an important component of the Cambrian evolutionary fauna. Eoglossa chengjiangensis from Chengjiang is the earliest known representative of the Glossellinae. Diandongia pista occurs abundantly both in the Chengjiang fauna and the younger Guanshan fauna, and it’s exceptionally well-preserved and strongly mineralized shells shows that it belongs within the Botsfordiidae. In contrast, the last two species from Chengjiang examined for this thesis - Yuganotheca elegans and Cotyledion tylodes belong within the stem of the Brachiopoda and the Lophotrochozoan entoprocts.

APA, Harvard, Vancouver, ISO, and other styles

15

Dudei, Nicole L. "The impact of the Richmondian Invasion on paleobiogeographic distribution of taxa in the Late Ordovician C₄ sequence (Richmondian Stage, Cincinnati, Ohio) including a comparison of range reconstruction methods." Ohio : Ohio University, 2009. http://www.ohiolink.edu/etd/view.cgi?ohiou1245437297.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Ostrow, D. Gigi, and n/a. "Larval dispersal and population genetic structure of brachiopods in the New Zealand fiords." University of Otago. Department of Marine Science, 2007. http://adt.otago.ac.nz./public/adt-NZDU20070308.144342.

Full text

Abstract:

New Zealand�s fourteen deep-water fiords have complex physical and hydrographic features as well as strong environmental gradients, all of which may influence the population structure of organisms that inhabit the fiords. I examined the population structure of the brachiopod Terebratella sanguinea over ecological and evolutionary time scales in relation to physical and hydrographic features of the fiords. To further explore the role of larval dispersal in this system, comparisons between population genetic structure of T. sanguinea and a brachiopod with a contrasting larval dispersal strategy (Liothyrella neozelanica) were made. Aspects of the life history of the articulate brachiopod Terebratella sanguinea were measured. I measured density and size throughout Doubtful Sound and growth at outer (5 km from outer coast) and inner fiord sites (13.5 km from outer coast). Additionally, reproductive periodicity was measured at a single site within Doubtful Sound. Terebratella sanguinea occurred at significantly lower densities and was significantly smaller at the outer fiord site (p < 0.05), however growth rates between an inner and outer fiord site did not differ significantly. Terebratella sanguinea was found to have separate sexes and synchronous maturation of oocytes with spawning occurring in the austral winter. These results indicated that, on an ecological time scale, the environmental gradient of the fiords influences aspects of T. sanguinea population structure. In order to determine the influence of the fiord environment on genetic population structure, patterns among T. sanguinea from across Fiordland were assessed using two genetic markers, and these data were compared to hydrodynamic variables. Ten sites (322 individuals) were included in a preliminary allozyme analysis, and 20 sites (358 individuals) were used for the amplified fragment length polymorphism (AFLP) analysis. Patchy genetic differentiation was revealed with both markers, and a break between Long Sound and the other Fiordland sites was detected with AFLP markers. My results suggest hydrodynamic features of this region may isolate organisms that can disperse only during a planktonic larval phase, however this isolation is visible in genetic patterns only at the most extreme values of the hydrodynamic variables. To better understand how the fiord environment influences population structure of organisms that disperse via planktonic larvae, I compared population genetic structure of two sympatric brachiopod species that differ in planktonic larval duration. Genetic analysis using the AFLP technique revealed population structuring corresponding to the contrasting modes of larval dispersal. AMOVA analysis indicated Liothyrella neozelanica, a brachiopod that broods its larvae, had more limited exchange among sites within a fiord than did T. sanguinea, a brachiopod that does not brood its larvae. In general, the fiord hydrographic conditions may be creating opportunities for local genetic differentiation (for example Long Sound) in organisms capable of longer distance dispersal, but organisms with lower potential for dispersal are more strongly influenced by ontogeny than by hydrography. Understanding the population structure of some of the marine fauna of Fiordland is an important cornerstone for the developing management plan for the area. Conservation of the underwater resources of this World Heritage Area can be successful if the structure of the system and the mechanisms driving this structure are taken into account.

APA, Harvard, Vancouver, ISO, and other styles

17

Layng, Alexander Patrick. "Two-dimensional landmark analysis of Spinocyrtid brachiopods of Euramerica during the Givetian." Thesis, University of Iowa, 2017. https://ir.uiowa.edu/etd/5799.

Full text

Abstract:

Recent inquiry into the nomenclature of several species within Spinocyrtia has led to questions concerning name applicability and validity, particularly whether Delthyris granulosa and Spinocyrtia (Spirifer) granulosa are synonymous. This study utilized two-dimensional outline landmark analysis, a form of geometric morphometric analysis, to evaluate interspecific variation among these species. I took over a thousand photographs of over a hundred specimens of brachiopods belonging to the family Spinocyrtiidae. Ninety-six specimens originated from the Givetian outcrop belt of New York state, three were from northwestern Ohio, there was single Canadian specimen, and there was a single German specimen. The results from these analyses indicate that the mophospaces of Spinocyrtia (Spirifer) congesta, S. (Spirifer) granulosa, and S?. (Spirifer) marcyi are statistically (p < 0.05) distinct from one another.

APA, Harvard, Vancouver, ISO, and other styles

18

Jaecks, Glenn Seward. "Investigating heterochrony in the fossil record : a geochemical, morphometric, and phylogenetic study of Thecideida (Brachiopoda), Triassic-recent /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2002. http://uclibs.org/PID/11984.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Klug, Christopher Allen. "Lower Permian through Lower Trassic [sic] paleontology, stratigraphy, and chemostratigraphy of the Bilk Creek Mountains of Humboldt County, Nevada." Bowling Green, Ohio : Bowling Green State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=bgsu1184878826.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Robert, Chloé. "Estimating the Early Evolution of Brachiopods Using an Integrated Approach Combining Genomics and Fossils." Thesis, Uppsala universitet, Paleobiologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-356883.

Full text

Abstract:

The Brachiopoda, a major group of the Lophotrochozoa, experienced a rapid early evolutionary diversification during the well-known Cambrian explosion and subsequently dominated the Palaeozoic benthos with its diversity and abundance. Even though the phylogeny of the Lophotrochozoa is still hotly debated, it is now known that the Brachiopoda are a monophyletic grouping. However, the early evolutionary rates for the Brachiopoda have never been studied in the framework of a study combining molecular data and fossil time calibration points. In order to investigate the expected higher evolutionary rates of the Phylum at its origin, we conducted phylogenetic studies combining different methodologies and datasets. This work has at its foundation Maximum Likelihood and Bayesian analyses of 18S and 28S rRNA datasets followed by analyses of phylogenomic sequences. All material was obtained from previously available sequences and from sequencing of genetic material from specimens from a concerted worldwide collection effort. While the analyses of the phylogenomic dataset produced a robust phylogeny of the Brachiopoda with good support, both the results of the novel rRNA and phylogenomic dating analyses provided limited insights into the early rates of evolution of the Brachiopoda from a newly assembled dataset, demonstrating some limitations in calibration dating using the software package BEAST2. Future studies implementing fossil calibration, possibly incorporating morphological data, should be attempted to elucidate the early rates of evolution of Brachiopoda and the effect of the Push of the Past in this clade.
Det är ofta antaget att evolution (förändringar i arvsmassan hos en grupp organismer) sker i en konstant hastighet men i slutändan ändå osäkert om så är fallet. Stora grupper av organismer har ofta associerats med en högre evolutionär hastighet, speciellt nära deras uppkomst, vilket ökar sannolikheten för överlevnad. Armfotingar (Brachiopoda) är marina ryggradslösa djur med skal som tidigare var allmänt spridd, idag är istället musslor (Bivalvia) betydligt mer spridda. Armfotingar har funnits och utvecklats under flera miljoner år med ursprung under tidigt kambrium. Genom år av forskning och många fossil har vi fått mer information om utseendet hos utdöda organismer vilket har bidragit till att antalet fossila arter som vi känner till har ökat tusenfalt. Under den senaste tiden har det också skett innovationer inom molekylära tekniker som gjort det möjligt att applicera dessa kunskaper även på utdöda arter. Dessa molekylära tekniker har nyligen hjälpt till att bestämma några av släktskapsförhållandena inom armfotingar som tidigare ansetts vara väldigt svåra att lösa. Det finns fortfarande vissa släktskapsförhållanden inom armfotingar som inte är kända och man vet ännu inte hur fort de utvecklades. Genom att undersöka just evolutionens hastighet kan man börja förstå gruppens tidiga framgång under Kambrium och Ordovicium samt minskningen som följde. Syftet med den här studien var att beräkna evolutionshastigheten hos armfotingar med särskild fokus på den tidiga diversifieringen av gruppen. För att undersöka detta använde vi oss av molekylära data för att analysera släktskapsförhållandena inom armfotingar. Dessutom använde vi fossil för att datera stora händelser i armfotingarnas evolutionära historia. Med hjälp av statistiska analyser kunde vi beräkna evolutionshastighet och släktskapsförhållandena inom gruppen. Vi kom fram till att armfotingar härstammar från en gemensam förfader. Dateringen kring när detta skedde blev inte fastställd då det beräknades ske miljoner år före det äldsta djurfossilet. Det kommer behövas mer forskning för att ta reda på om armfotingar hade en högre evolutionär hastighet i tidigt skede.

APA, Harvard, Vancouver, ISO, and other styles

21

Griškonytė, Ieva. "Minijos regioninio aukšto geocheminiai uolienų ir brachiopodų tyrimai." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2009. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2007~D_20090908_194022-85278.

Full text

Abstract:

MINIJOS REGIONINIO AUKŠTO GEOCHEMINIAI UOLIENŲ IR BRACHIOPODŲ TYRIMAI SANTRAUKA Vadinamos “karbonatinės sistemos” uždarumas/atvirumas turi didelę reikšmę nustatant sedimentacinio baseino aplinkos sąlygas. . Tik tuo atveju, kai sistemos yra uždaros ( arba uždaros pagrindinių elementų atžvilgiu) atitinkamos diagenezės nustatymui (ištirpinimas, cementacija), gali būti padarytas poveikis poringumui ir skvarbumui. Kai uolienų sistemos yra uždaros, ištirpinimas vyksta dėl pirminės nestabilios ar metastabilios mineraloginės grūdelių sudėties (aragonito, kalcito su padidintu Mg kiekiu) arba dėl grūdelių dydžio ir struktūros (veikiant į paviršiaus plotą palyginti su tūriu), to pasekoje prinešama medžiaga cementacijai (cementacija tokiu būdu paprasčiausiai yra sistemos viduje karbonatinės medžiagos persiskirstymo rezultatas). Brachiopodų geledelės yra sudarytos iš kalcito su nedideliu magnio kiekiu, dėl to, manoma, jie atspindi pirminę paleovandenyno vandens cheminę sudėtį. Tyrimų medžiaga yra Minijos regioninio aukšto uolienų ir iš tų pačių gylio intervalų paimti brachiopodų Isorthis ovalis geldelių mėginiai. Tyrimams viso buvo paimta 18 uolienų ir brachiopodų mėginių iš 11 skirtingų gręžinių, išilgai Lietuvos Vakarinės – Centrinės ir Pietvakarinės krypties. Tiek uolienose, tiek brachiopoduose buvo tiriami Ca, Mg, Fe, Mn ir Sr kiekiai, gauti rezultatai buvo lyginami tarpusavyje su tikslu įvertinti Minijos regioninio aukšto uolienų diagenezės sąlygas. Tirtų cheminių elementų kiekiai ir... [toliau žr. visą tekstą]
GEOCHEMISTRY OF ROCKS AND BRACHIOPODS OF MINIJA REGIONAL STAGE SUMMARY The so-called closeness/openness of carbonate system is still a big problem in predicting reservoir properties. Only when the systems are closed (or closed with respect to major elements) adequate prediction of diagenesis (e.g. dissolution, cementation) and the effect on porosity and permeability can be made. When systems would be closed, dissolution because of unstable or metastable primary mineralogical composition of grains (aragonite, high-Mg calcite) or because of grain size and texture (reactive surface area versus volume) would deliver the material for cementation (in fact cementation is thus merely the result of redistribution of carbonate within the system). Brachiopods precipitate low – Mg calcite shells and have a high potencial for retaining their primary chemical composition of palaeoseawater. The sample material in this study was cleaned brachiopod shells (Isorthis ovalis) and the associated whole rock carbonates. For the analysis we took 18 samples of rocks and brachiopods, from 11 different boreholes, which are located from West – Central to South part of Lithuania. Both, brachiopods and associated rocks samples were analysed for Ca, Mg, Fe, Mn and Sr and the results were compared in order to assess in how far carbonate material was added to the Silurian system during burial. The study of Ca, Mg, Fe, Mn and Sr chemical element contents suggests that in Central and South part of Lithuania... [to full text]

APA, Harvard, Vancouver, ISO, and other styles

22

Egerquist, Eva. "Ordovician (Billingen and Volkhov stages) Brachiopod Faunas of the East Baltic." Doctoral thesis, Uppsala University, Palaeontology group, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4303.

Full text

Abstract:

Lower-Middle Ordovician (Arenig) successions in the East Baltic have been investigated for more than one hundred and fifty years. Nevertheless detailed sampling still yields new species and better knowledge of the environment in which these organisms lived. The successions are well suited for bed by bed sampling because of the lack of tectonic disturbance and because the sequences are well documented.

This study analyses collections of Billingen-Volkhov age mainly from the St. Petersburg region, but also from Estonia. A great deal of the material was obtained from the marly to clayey, soft sediment that intercalates the compact packstones and wackestones in the succession. Twenty-nine of these clay horizons were used for diversity estimates on the fauna through the succession. The most thoroughly investigated groups for this investigation were rhynchonelliformean brachiopods, conodonts and ostracodes. The results indicate that variances in diversity and abundance levels for these groups were not correlated, either to each other or to the small-scale sea level fluctuations that have been suggested for the region. However, diversity dynamics of brachiopods and ostracodes confirm the large-scale upward shallowing of the basin into the Upper Volkhov. Comparison with fossils from the limestones did not reveal any differences in faunal composition between the two preservation modes.

The detailed sampling, coupled with sampling of the recently described mud mounds that occur in several outcrops, yielded large numbers of specimens. This enabled revision of earlier poorly known rhynchonelliformean genera such as Ujukella Andreev, as well as better known genera such as Porambonites Pander. In total the examined faunas include 31 genera assigned to 53 species of rhynchonelliformean brachiopods. Of these Leoniorthis and Eoporambonites are defined as new genera, and the following new species are described: Neumania paucicostata, Ranorthis rotunda, Orthidium gambolovensis, Orthidium lavensis, Skenidioides minutus, Tetralobula peregrina, Idiostrophia prima and Idiostrophia tenuicostata.

APA, Harvard, Vancouver, ISO, and other styles

23

Comniskey, Jeanninny Carla. "Paleontologia dos Discinidae (Brachiopoda: Linguliformea) da sucessão devoniana da Bacia do Paraná, Estado do Paraná, Brasil: Revisão sistemática, distribuição geográfica e estratigráfica." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2011. http://tede2.uepg.br/jspui/handle/prefix/543.

Full text

Abstract:

Made available in DSpace on 2017-07-21T18:13:48Z (GMT). No. of bitstreams: 1 Jeanninny Comniskey.pdf: 5522788 bytes, checksum: 549fd8a645e09159673d8bc21ef5872b (MD5) Previous issue date: 2011-03-24
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The present paper is about branchiopods discinids that occur from the Devonian succession in the state of Paraná, Brazil. The following themes were discussed: systematic review, basic taphonomic analysis and a geographic distribution and stratigraphic. The fieldworks were developed with the intuition of collecting material with stratigraphic control. It was recorded four species of discinids: Orbiculoidea baini, Orbiculoidea bodenbenderi, Orbiculoidea excentrica e Gigadiscina collis. The discinids occur from the Neopraguiano until at least Eogivetiano. The stratigraphic and geographic distribution varies with the species. Considering about the extinction of the group, along with its collapse of the malvinokaffric fauna is also presented. The transference from Orbiculoidea collis taxon to Gigadiscina collis and its maintenance of the others species with originals descriptions added to new data are also presented.
O presente trabalho trata dos braquiópodes discinídeos ocorrentes na sucessão devoniana do estado do Paraná, Brasil. Foram abordados os seguintes temas: revisão sistemática, análise tafonômica básica e distribuição geográfica e estratigráfica. Trabalhos de campo foram desenvolvidos no intuito de se coletar material com controle estratigráfico preciso. Registrou-se quatro espécies de discinídeos quais sejam: Orbiculoidea baini, Orbiculoidea bodenbenderi, Orbiculoidea excentrica e Gigadiscina collis. Os discinídeos ocorrem desde o Neopraguiano até pelo menos o Eogivetiano. A distribuição geográfica e estratigráfica varia de acordo com a espécie. Considerações sobre a extinção do grupo, juntamente com o colapso da fauna malvinocáfrica é ainda apresentado. A transferência do táxon Orbiculoidea collis para Gigadiscina collis e a manutenção das demais espécies com descrições originais adicionadas de novos dados são também apresentadas.

APA, Harvard, Vancouver, ISO, and other styles

24

Butler, Aodhán D. "Decoding the fossil record of early lophophorates : Systematics and phylogeny of problematic Cambrian Lophotrochozoa." Doctoral thesis, Uppsala universitet, Paleobiologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-261907.

Full text

Abstract:

The evolutionary origins of animal phyla are intimately linked with the Cambrian explosion, a period of radical ecological and evolutionary innovation that begins approximately 540 Mya and continues for some 20 million years, during which most major animal groups appear. Lophotrochozoa, a major group of protostome animals that includes molluscs, annelids and brachiopods, represent a significant component of the oldest known fossil records of biomineralised animals, as disclosed by the enigmatic ‘small shelly fossil’ faunas of the early Cambrian. Determining the affinities of these scleritome taxa is highly informative for examining Cambrian evolutionary patterns, since many are supposed stem-group Lophotrochozoa. The main focus of this thesis pertained to the stem-group of the Brachiopoda, a highly diverse and important clade of suspension feeding animals in the Palaeozoic era, which are still extant but with only with a fraction of past diversity. Major findings include adding support for tommotiid affinity as stem-group lophophorates. Determining morphological character homologies vital to reconstructing the brachiopod stem-group was achieved by comparing Cambrian Lagerstätten with the widespread biomineralised record of Cambrian stem-brachiopods and small shelly fossils. Polarising character changes associated with the putative transition from scleritome organisms to crown-group brachiopods was furthered by the description of an enigmatic agglutinated tubular lophophorate Yuganotheca elegans from the Chengjiang Lagerstätte, China, which possesses an unusual combination of phoronid, brachiopod and tommotiid characters. These efforts were furthered by the use of X-ray tomographic techniques that revealed novel anatomical features, including exceptionally preserved setae in the tommotiid Micrina. The evidence for a common origin of columnar brachiopod shell structures in the tommotiids is suggested and critically examined. Enigmatic and problematic early and middle Cambrian lophotrochozoans are newly described or re-described in light of new evidence, namely: the stem-brachiopod Mickwitzia occidens Walcott from the Indian Springs Lagerstätte, Nevada; a putative stem-group entoproct Cotyledion tylodes Luo and Hu from Chengjiang, China; a new enigmatic family of rhynchonelliform brachiopods exemplified by the newly described Tomteluva perturbata from the Stephen Formation, Canada; and the tommotiid Micrina etheridgei (Tate) from the Flinders Ranges, South Australia. Cladistic analyses of fossil morphological data supports a monophyletic Brachiopoda.

APA, Harvard, Vancouver, ISO, and other styles

25

Baxter, Mary Elizabeth. "A revised classification for certain genera of the families Uncinulidae, Hebetoechiidae, Obturamentellidae, Glossinotoechiidae, Hypothyridinidae and Hadrohynchiidae of the superfamily Uncinuloidea, order Rhynchonellida, phylum Brachiopoda /." view abstract or download file of text, 1999. http://wwwlib.umi.com/cr/uoregon/fullcit?p9955912.

Full text

Abstract:

Thesis (Ph. D.)--University of Oregon, 1999.
"Table 1," 216 cm. x 74 cm., folded to 26 cm. x 17 cm., in pocket of vol. 1. Typescript. Includes vita and abstract. Includes bibliographical references (leaves 548-568). Also available for download via the World Wide Web; free to University of Oregon users. Address: http://wwwlib.umi.com/cr/uoregon/fullcit?p9955912.

APA, Harvard, Vancouver, ISO, and other styles

26

Anelli, Luiz Eduardo. "Invertebrados Neocarboníferos das formações Piauí (Bacia do Parnaíba) e Itaituba (Bacia do Amazonas): taxonomia; análise cladística das subfamílias oriocrassatellinae (crassatellacea, bivalvia) e neospiriferinae (spiriferoidea, brachiopoda)." Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/44/44136/tde-26072013-153442/.

Full text

Abstract:

A presente tese trata dos resultados de estudo de sistemática paleontológica da fauna de invertebrados da Formação Piauí (Neocarbonífero, Bacia do Parnaíba). Adicionalmente, duas espécies de braquiópodes e uma espécie de bivalve da Formação Itaituba (Neocarbonífero, Bacia do Amazonas) foram descritas. A fauna de invertebrados marinhos da Formação Piauí é a segunda mais diversificada e abundante do Neopaleozóico do país. Incluindo os bivalves anteriormente tratados (Anelli, 1994, Dissertação de Mestrado), 51 espécies são atualmente reconhecidas na formação. Dentre os moluscos, o grupo mais abundante é o dos bivalves, com 30 espécies (58%), seguido dos gastrópodes, com 9 espécies (17%) e 1 cefalópode (2%). Os braquiópodes, segundo grupo em abundância, compreendem 9 espécies (17%), atribuídos as ordens Acrotretida (1 espécie), Strophomenida (1 espécie), Productida (5 espécies) e Spiriferida (2 espécies). Trilobites (1 espécie) e briozoário (1 espécie) ocorrem subsidiariamente na fauna. Dentre as 25 espécies da Formação Piauí aqui tratadas, 3 espécies, Bellerophon (Pharkidonotus) sp. n. (gastrópode), Pteronites sp. n. (bivalve) e uma nova combinação, Palladin plummeri n. comb. (trilobites), são novas para a ciência. Foram ainda identificadas 2 novas espécies de braquiópodes, Neospirifer sp. n. 1, Neospirifer sp. n. 2, e um molusco bivalve, cf. Edmondia sp., na Formação Itaituba. A distribuição geológica das espécies reconhecidas indica uma idade pensilvaniana para a Formação Piauí, concordantemente, com a cronologia paleontológica conhecida da formação (Andares Atokano, Morrowano, podendo atingir a base do Desmoinesiano), estabelecida com base em conodontes. Aproximadamente a mesma idade é indicada por conodontes e fusulinídeos para a Formação Itaituba, Bacia do Amazonas. A composição das faunas das formações Piauí e Itaituba mostra fortes similaridades taxonômicas, confirmando sua contemporaneidade, bem como a provável ligação geográfica entre as duas bacias no Pensilvaniano médio. Faunas do Meio-Oeste americano, incluindo as da Formação Amsden (Wyoming), e da seqüência desmoinesiana do sudeste do Missouri, EUA, mostram também fortes afinidades paleontológicas com as assembléias estudadas. Faunas sul-americanas de idade pensilvaniana correlacionáveis em menor grau, incluem as da Formação Cerro Prieto (Montanhas Amotape, Peru), Seção La Jagua e Formação Palmarito, Venezuela. Além da abordagem taxonômica tradicional utilizada na análise das assembléias estudadas, o presente estudo inclui ensaios de análise cladística de alguns grupos representados por espécimes bem preservados e mais abundantes. Estes incluem táxons da subfamília Oriocrassatellinae (Mollusca, Bivalvia) e dos Productida e Spiriferoidea (Brachiopoda). Os resultados obtidos permitiram visualizar alguns dos problemas taxonômicos atualmente existentes relativos à sistemática desses táxons. A análise cladística não ponderada da subfamília Oriocrassatellinae Boyd & Newell, 1968, mostra as relações de parentesco entre 16 espécies do gênero Oriocrassatella, bem como a existência de dois grupos monofiléticos, consistentes com as reconstruções paleográficas do final do Paleozóico. De acordo com esta análise, parte dos táxons da superfamília Crassatellacea são inconsistentes com a sistemática tradicional do grupo. A análise ponderada, por sua vez, embora não demonstre uma forte tendência de agrupamento de formas laurásicas e gondwânicas, é largamente coincidente com as propostas de agrupamentos de famílias e subfamílias da superfamília Crassatellacea mostrados nos esquemas de classificação disponíveis. A análise cladística auxiliou ainda na identificação de espécies monofiléticas e parafiléticas, no âmbito da superfamília. Uma análise cladística preliminar dos braquiópodes productídeos, baseada em lista de caracteres da literatura, foi executada com o fim de testar o tratamento sistemático atual de espécimes da Formação Itaituba e as hipóteses de atribuição taxonômica do material da Formação Piauí aqui descrito. A sistemática conhecida dos productídeos da Formação Itaituba só é em parte corroborada pelos resultados da análise cladística e carecem de revisão. Espécimes da Formação Piauí, embora preservados apenas como moldes, exibem caracteres úteis na identificação das superfamílias. A análise cladística da subfamília Neospiriferinae indica esse táxon como não monofilético. Resultados preliminares da análise cladística de grande parte dos táxons atribuídos à superfamília Spiriferoidea mostra a família Trigonotretidae, bem como as subfamílias Neospiriferinae e Trigonotretidae, como agrupamentos parafiléticos. Toda a coleção da Formação Itaituba atribuída por Mendes (1966) a Neospirifer dresseri parece agrupar três espécies distintas.
The present thesis covers the systematic paleontology of the invertebrate fauna from the Piauí Formation (Late Carboniferous, Parnaíba Basin). Additionally, two brachiopods and one bivalve species, from the Itaituba Formation (Late Carboniferous, Amazon Basin) are also described. The invertebrate marine assemblage from the Piauí Formation is the second most diversified and abundant in the Brazilian Neopaleozoic. With the inclusion of the bilvalves studied by Anelli (1994, Master Dissertation), 51 species are recognized. Among the molluscans, the bivalves are the best represented group, including 30 species (58%), followed by nine species of gastropods (17%), and one of cephalopods (2%). The brachiopods, the second best group represented, include nine species (17%), attributed to the acrotretids (1 species), strophomenids (1 species), productids (5 species) and spiriferids (2 species). One species of trilobite and one of the bryozoa are also described in the Piauí assemblage. Among the 25 species from the Piauí Formation treated here, three species, Bellerophon (Pharkidonotus) sp. n. (gastropod), Pteronites sp. n. (bivalve) and the combination, Palladin plummeri n. comb. (trilobite), are new to science. Two new species of brachiopods, Neospirifer sp. n. 1, Neospirifer sp. n. 2 and a new bivalve, cf. Edmondia sp., are identified in the Itaituba Formation. The geological distribution of the recognized species indicates a Pennsylvanian age for the Piauí assemblage, corroborating the age determination based on conodonts (Atokan-Morrowan, including the lower part of the Desmoinesian) for the Piauí Formation and on conodonts and fusulinids for the Itaituba Formation. The faunas from the Piauí and Itaituba Formations show close taxonomic similarity, supporting the contemporaneity and probable geographic link between the two basins in the Middle Pennsylvanian. Other faunas showing close taxonomic similarities with the Brazilian ones are those from the American Mid-Continent, including faunas from the Amsden Formation, from Wyoming, and the Desmoinesian sequence of southeast Missouri. South American Pennsylvanian faunas showing affinities to the Piauí Formation include those of the Cerro Prieto Formation (Amotape Mountains, Peru) and the La Jagua Series and Palmarito Formation, Venezuela. In addition to the traditional taxonomic approach, this study also includes the cladistic analysis of some well-represented groups. Taxons analysed include the subfamily Oriocrassatellinae (Bivalve, Crassatellacea) and the Productidina and Spiriferoidea (Brachiopoda). Results of the analysis led to the recognition of problems related to the systematics of these groups. The unweighted analysis of the subfamily Oriocrassatellinae Boyd & Newell (1968) revealed the phylogenetic relationships of 16 species of the genus Oriocrassatella and identified two monophyletic groups, thus corroborating the paleogeographical reconstructions during the late Paleozoic. According to this analysis, part of the taxons of the superfamily Crassatellacea are not in agreement with the traditionally accepted systematics of the group. The weighted analysis, although not corroborating the paleogeographical groups, is consistent with the groupings of families and subfamilies of the Crassatellacea as traditionally understood. The cladistic analysis also helped in the identification of monophyletic and paraphyletic species. A preliminary analysis of the productids based on a list of characters presented in the literature was carried out to test the systematics of species from the Itaituba Formation as well as the preliminary systematics of the material from the Piauí Formation. The systematics previously proposed for the Itaituba productids only partially agrees with results of the cladistic analysis and needs revision. Specimens from the Piauí Formation, although preserved as moulds, show sufficient characters for grouping species into superfamilies. Cladistic analysis indicates that the subfamily Neospiriferinae is paraphyletic. Preliminary results for most of the taxons of the superfamily Spiriferoidea show the Trigonotretidae, as well as Neospiriferinae and Trigonotretinae, as paraphyletic groups. All specimens from the Itaituba Formation assigned by Mendes (1966) to Neospirifer dresseri may be polyspecific, as indicated in the cladograms.

APA, Harvard, Vancouver, ISO, and other styles

27

Bassett-Butt, Lewis. "The Cambrian lophotrochozoans of the Transantarctic Mountains, Antarctica." Licentiate thesis, Uppsala universitet, Paleobiologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-252137.

Full text

Abstract:

The origin of many lophotrochozoan groups can be traced to “small shelly fossil” (SSF) faunas of the Early Cambrian. Antarctica is a key region of study, due to the continent’s known close geographical proximity to well-studied Australian and Indian basins in in the Cambrian. Few studies have focused on this region however, due to a paucity of data. Re-examination of camenellan sclerites from the Early Cambrian Shackleton Limestone of the Churchill Mountains of Antarctica has revealed a previously unidentified species of Dailyatia in the formation, co-occurring alongside previously described Dailyatia odyssei Evans and Rowell, 1990, as in the Arrowie Basin of Australia. Re-examination of material previously described as Kennardia sp. A and Kennardia sp. B has indicated that these taxa can likely be synonymized as a second species of Dailyatia. Dailyatia sclerites were also found in the temporally equivalent “Schneider Hills Limestone” formation, which cropsout in the Argentina Range of Antarctica. These specimens appear to belongto a third species of Dailyatia, suggesting that the spatial distribution of tommotiids in the Early Cambrian was more complex than previously recognized, and that the group may be useful in future biostratigraphic studies. A study ofthe Middle Cambrian (Drumian Stage) Nelson Limestone Formation of the Neptune Range, Antarctica has revealed a moderately diverse brachiopod and trilobite fauna. The brachiopods have strong faunal links to taxa from South Australia and India, as well as other parts of the Antarctic province, fitting independent strong evidence for a united East Gondwanan region in the Middle Cambrian. An unidentified camenellan tommotiid sclerite is also described from the Nelson Limestone. This extends the worldwide temporal range of the tommotiid clade into the Drumian Stage, and suggests that more basal members of the brachiopod stem-group survived to form part of a more diverse Middle Cambrian fauna.

APA, Harvard, Vancouver, ISO, and other styles

28

Gourvennec, Rémy. "Brachiopodes spiriferida du dévonien inferieur du massif armoricain : systématique, paléobiologie, évolution, biostratigraphie." Brest, 1987. http://www.theses.fr/1987BRES2033.

Full text

Abstract:

Cet ouvrage est consacré aux spiriferides du dévonien inferieur du massif armoricain. L’étude systématique comprend la description de 51 espèces dont 17 nouvelles et 6 laissées en nomenclature ouverte; elle est complétée par une étude biométrique. Le chapitre consacre à la biologie traite de la morphologie fonctionnelle, de la croissance de la coquille, de paléoécologie et de l'étude des microsculptures et de leurs implications. On montre la prédominance des modalités évolutives de type anagénétique. L’étude de plusieurs coupes de référence permet d'établir la succession des espèces et de proposer des corrélations entre les différents domaines du massif armoricain et ceux de la péninsule ibérique.

APA, Harvard, Vancouver, ISO, and other styles

29

Saulnier, Ségolène. "Exploration des compositions isotopiques en magnésium des carbonates marins comme traceurs paléoenvironnementaux." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0267/document.

Full text

Abstract:

L'utilisation des compositions isotopiques en Mg des carbonates marins peut permettre l'étude du cycle biogéochimique de cet élément. Ainsi, les carbonates sont susceptibles d'enregistrer la composition isotopique de Mg de l'océan lors de leur précipitation. Cependant, il est nécessaire de comprendre les facteurs environnementaux (e.g. température, pH, Mg/Ca de la solution) qui peuvent contrôler ces compositions. Le premier objectif de cette thèse a donc été de déterminer les paramètres pouvant impacter les compositions isotopiques de Mg des carbonates par des précipitations expérimentales en conditions contrôlées. Il a ainsi été mis en évidence, dans les gammes considérées, mais qui restent restreintes, l'absence de contrôle de la température, du pH et du Mg/Ca de la solution sur le fractionnement isotopique du Mg lors de la précipitation des carbonates. Le fractionnement isotopique du Mg entre la solution et la calcite, à l'équilibre, a été évalué à -2,13 ± 0,24 pour mille (2sigma) à partir de cette étude, combinée à des données de la littérature. Ces résultats ont ensuite été appliqués à l'étude des compositions isotopiques de Mg dans des coquilles de brachiopodes à la fois modernes et anciens. Pour cela, une quantification des effets vitaux vis-à-vis des isotopes du Mg lors de la croissance du brachiopodes a été réalisée. Ainsi, les zones en équilibre isotopique pour Mg, O et C et donc susceptibles d'être utilisables lors des reconstructions paléoenvironnementales sont situées au sein de la calcite interne sur les bords de la coquille. Les premières mesures des compositions isotopiques de Mg sur les derniers 60 Ma suggèrent des variations de la composition isotopique du Mg de l'océan qui pourraient être liées à un changement du flux de carbonate à l'océan
Studying the Mg isotopic composition in marine carbonate can help to understand the biogeochemical cycle of this element. Indeed, carbonates may record seawater Mg isotopic composition during their precipitation. However, it is necessary to understand the possible control of some environmental factors (e.g. temperature, pH, Mg/Ca of the solution) on those compositions. Therefore, the first goal of this thesis was to determine parameters impacting carbonate Mg isotopic composition with experimental precipitations under controlled conditions. Thus, it has been shown, in restricted ranges, that temperature, pH and solution Mg/Ca have no influence on Mg isotopic fractionation during calcite precipitation. Equilibrium Mg isotopic fractionation between solution and calcite has been evaluated to -2.13 ± 0.24 per thousand (2sigma) from this study, combined with published data. These results were then applied to a study of Mg isotopic compositions in modern and past brachiopod shells. For this, a quantification of vital effects with respect to Mg isotopes during the brachiopod growth was realized. The zones in isotopic equilibrium for Mg, O and C, and thus susceptible to be used for paleoenvironnemental reconstruction, are in the inner calcite at the edge of the shell. The first measurements of Mg isotopic compositions for the last 60 Ma suggest variations of Mg isotopic compositions of the seawater which could be linked to changes of carbonate flux in the ocean

APA, Harvard, Vancouver, ISO, and other styles

30

Skovsted, Christian B. "The Early Cambrian Fauna of North-East Greenland." Doctoral thesis, Uppsala University, Department of Earth Sciences, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3910.

Full text

Abstract:

Small shelly fossils are common in sediments of Early Cambrian age and include the earliest common representatives of metazoan animals with mineralized hard parts. The group includes fossils of very different morphology, composition and ultrastructure. They seem to represent skeletal remains of numerous animal groups, the biological affinities of which are largely unresolved. However, the wide geographic range of many forms has the potential to enhance biostratigraphic and palaeogeographic resolution in the Early Cambrian.

The late Early Cambrian sequence of North-East Greenland has yielded an assemblage of more than 88 species of small shelly fossils, brachiopods and trilobites, indicative of a middle Dyeran age (Botoman equivalent). The recovered fossils include a number of species that are known from other Early Cambrian palaeocontinents, and particularly strong ties to late Early Cambrian faunas of Australia are documented. The many cosmopolitan taxa thus identified suggests a close juxtaposition of palaeocontinents at this time.

The systematic affinity of many of these small shelly fossils is poorly understood, partly because of their fragmentary nature and poor preservation. However, new data from North-East Greenland improves our understanding of the function and biological affinity of certain taxa. Collections of the problematic fossil Mongolitubulus from North and North-East Greenland exhibit characters indicative of a defensive function as spines of bivalved arthropods, while species of the problematic genus Triplicatella represent the opercula of an unknown tubular shell, probably related to orthothecid hyoliths. The bivalved fossil Mickwitzia from North-East Greenland combines characters of linguliform brachiopods and sclerites of Micrina, a non-bivalved problematic form (halkieriid) from Australia. The combination suggests that Mickwitzia is a stem group brachiopod and strengthens arguments for a halkieriid ancestry of the brachiopod phylum.

APA, Harvard, Vancouver, ISO, and other styles

31

Harper, D. A. T. "Diversification of the Ordovician brachiopod fauna." Thesis, Queen's University Belfast, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426983.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Piazza, Veronica. "Response of early Toarcian (Early Jurassic) benthic marine faunas from South-Western Europe to temperature-related stressors." Doctoral thesis, Humboldt-Universität zu Berlin, 2021. http://dx.doi.org/10.18452/22950.

Full text

Abstract:

Globaler Temperaturanstieg, Ozeanversauerung und Sauerstoffmangel (temperaturbedingte Stressoren), spielen eine wichtige Rolle während Klimawandel. Die kombinierten Auswirkungen wirken sich negativ auf marine Lebensgemeinschaften und Ökosystemen aus und verschärfen die Effekte anderer Stressoren. Es gibt für den aktuellen und vergangenen Erwärmungsphasen Belege für veränderte Artenverteilung, Lebensraumverlust, Artensterben und verminderte physiologische Leistungen von Organismen. Die spezifischen Mechanismen werden diskutiert. Umweltveränderungen in der Erdvergangenheit bieten die Gelegenheit, die Dynamik von Ökosystemkrisen vor, zu untersuchen. Diese Arbeit integriert verschiedenen Disziplinen um unser Verständnis der Rolle temperaturbedingter Stressoren für marine benthische Ökosysteme zu verbessern. Das Toarcian Event (Unterjura) wurde aufgrund seiner geologischen, geochemischen und paläontologischen Überlieferung ausgewählt. Hochaufgelöste quantitative taxonomische, paläoökologische und geochemische Daten von benthischen Makroinvertebraten wurden analysiert. Ziel ist es, die Mechanismen ökologischer Veränderungen unter Temperaturstress zu bewerten, mit Schwerpunkt auf Körpergrößenmuster sowie Veränderungen in der Zusammensetzung und Struktur von Lebensgemeinschaften, und die Rolle von Umweltstressoren als Ursachen der biotischen Krise abzuschätzen. Der Temperaturanstieg führte zu dem Verlust an biologischer Vielfalt und zu der Verringerung der Körpergröße der Organismen vor und während der biotischen Krise. Die Struktur der Gemeinschaften wurde in Bezug auf die taxonomische und ökologische Zusammensetzung neu organisiert. Die Reaktion auf Umweltstress war innerhalb und zwischen den taxonomischen Gruppen unterschiedlich, wobei Brachiopoden stark betroffen waren. Diese Ergebnisse verbessern unser Verständnis der biotischen Reaktionen auf temperaturbedingte Stressoren und können zur Vorhersage Veränderungen Ökosysteme bei den aktuellen Erwärmungstrends beitragen.
Global warming, oceanic acidification and deoxygenation (temperature-related stressors) play an important role during climate change. The combined impact of these stressors is known to negatively affect marine biota and ecosystems, often exacerbating the impact of other stressors. Under the current and past climate change, there is record of altered species distribution, habitat loss, extinctions and decreased physiological performance of organisms. Despite the increasing evidence, the specific mechanisms through which climate change influences ecological patterns are debated. Past environmental perturbations represent an opportunity to investigate the dynamics of ecosystem and biotic crises across Earth history. This work integrates different disciplines to increase our understanding on the role played by temperature-related stressors on marine benthic biota and ecosystems. The Toarcian Event (Early Jurassic) was chosen for its well-preserved geological, geochemical and palaeontological record. High-resolution quantitative faunal and geochemical data from benthic marine macroinvertebrates were investigated. The aims are to identify and evaluate the mechanisms of faunal and ecological shifts under a temperature-related stressor scenario, with focus on body size patterns and ecosystem change and recovery, and to estimate the role of environmental stressors as proximate causes of the biotic crisis. Temperature increase led to biodiversity loss and reduced body size of organisms during and possibly before the event. Moreover, the structure of marine communities was reorganized in terms of taxonomic and ecological composition. The response to environmental stress was variable within and between taxonomical groups, with brachiopods severely affected. These findings increase our understanding of biotic responses and ecosystem and biodiversity shifts under temperature stress, hopefully contributing to the prediction of ecosystem changes under the current warming scenario.

APA, Harvard, Vancouver, ISO, and other styles

33

Clegg, Heather. "Biomolecules in recent and fossil articulated brachiopods." Thesis, University of Newcastle Upon Tyne, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334162.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Evangelisti, Francesca <1978&gt. "Mediterranean brachiopods: morphological, ecological and phylogenetic aspects." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2738/1/Evangelisti_Francesca_Tesi.pdf.

Full text

Abstract:

The Brachiopoda of the Marine Protected Area “Secche di Tor Paterno”, Central Tyrrhenian Sea, have been investigated in order to give a first glance of the diversity of the brachiopods of this area and provide a new report on the Mediterranean Brachiopod fauna. Four species were reported: Novocrania anomala (Müller, 1776), Megathiris detruncata (Gmelin, 1790), Joania cordata (Risso,1826) and Argyrotheca cuneata (Risso,1826). For all the four species a morphological analysis was carried out. For the two most abundant species, J.cordata and A. cuneata, a morphometric study, based on thickness/width and length/width scattergrams, was carried out, in order to investigate their variability. Size-frequency distributions relative to the three dimensions of the shell were also computed, aimed at a evaluation of population dynamics of these two species. The results showed that, for both species, the parameters which most determine the rise of the shell during the growth of animal are width and length and that frequency distributions are mainly bi- or plurymodal and that they are difficult to interpret, as reported by other studies. Analysis of drill holes found on the shell of some specimens of the two same species revealed a predatory origin and that three different predators are responsible for them. Partial sequences of two different genetic markers, the Internal Transcribed Spacer 1 (ITS1) and the cytochrome oxidase subunit 1 (COI), were used to investigate the phylogenetic relationship between two populations of the eurybathic brachiopod species Gryphus vitreus (Born,1778) across the strait of Gibraltar. This represents the first genetic population study on brachiopods. Results from AMOVA and Bayesian analysis performed on 31 specimens highlighted no genetic differentiation indicating a likely panmixia, dispite the lecitotrophic development of the species.

APA, Harvard, Vancouver, ISO, and other styles

35

Evangelisti, Francesca <1978&gt. "Mediterranean brachiopods: morphological, ecological and phylogenetic aspects." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2738/.

Full text

Abstract:

The Brachiopoda of the Marine Protected Area “Secche di Tor Paterno”, Central Tyrrhenian Sea, have been investigated in order to give a first glance of the diversity of the brachiopods of this area and provide a new report on the Mediterranean Brachiopod fauna. Four species were reported: Novocrania anomala (Müller, 1776), Megathiris detruncata (Gmelin, 1790), Joania cordata (Risso,1826) and Argyrotheca cuneata (Risso,1826). For all the four species a morphological analysis was carried out. For the two most abundant species, J.cordata and A. cuneata, a morphometric study, based on thickness/width and length/width scattergrams, was carried out, in order to investigate their variability. Size-frequency distributions relative to the three dimensions of the shell were also computed, aimed at a evaluation of population dynamics of these two species. The results showed that, for both species, the parameters which most determine the rise of the shell during the growth of animal are width and length and that frequency distributions are mainly bi- or plurymodal and that they are difficult to interpret, as reported by other studies. Analysis of drill holes found on the shell of some specimens of the two same species revealed a predatory origin and that three different predators are responsible for them. Partial sequences of two different genetic markers, the Internal Transcribed Spacer 1 (ITS1) and the cytochrome oxidase subunit 1 (COI), were used to investigate the phylogenetic relationship between two populations of the eurybathic brachiopod species Gryphus vitreus (Born,1778) across the strait of Gibraltar. This represents the first genetic population study on brachiopods. Results from AMOVA and Bayesian analysis performed on 31 specimens highlighted no genetic differentiation indicating a likely panmixia, dispite the lecitotrophic development of the species.

APA, Harvard, Vancouver, ISO, and other styles

36

Meidlinger, Karen. "Reproductive ecology of the Antarctic brachiopod Liothyrella uva." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242863.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

YE, FACHENG. "THE MICROSTRUCTURE OF MODERN AND FOSSIL BRACHIOPOD ARCHIVES." Doctoral thesis, Università degli Studi di Milano, 2019. http://hdl.handle.net/2434/625022.

Full text

Abstract:

Due to their high biodiversity and widespread distribution in the Phanerozoic oceans, brachiopods are very important tools for research in palaeontology and related fields in Earth Sciences to investigate the past and present global change. Their biominerals have been considered the best carbonate archives of proxies for extending climate and environmental records on a broad geographical scale over long periods of time. Their fidelity as archives is supported by the following: 1) they record the physical and chemical composition of the seawater in which they live without, or with very limited, vital effects; 2) they precipitate a low-Mg calcite shell, which withstands post-depositional alteration; and 3) they are low metabolic and physiologically unbuffered animals sensitive to change in the physicochemical composition of the ambient seawater. However, there is still insufficient knowledge of the microstructures of these biomineral archives and their biomineralization processes during the evolutionary history of the phylum. The aims of the present thesis, focused on solving these issues, are to: 1) examine the micro- and morpho- structural diversity of modern and fossil brachiopods, 2) assess the microstructure variation in different environmental conditions; and 3) reconstruct the evolutionary changes and fabric differentiation of the main brachiopod classes through geological time. A multidisciplinary approach was used for the microstructural analyses: 1) a comprehensive dataset was established based on detailed microstructural observations of modern and fossil brachiopods analysed by Scanning Electron Microscopy (SEM); 2) new measurement methods were developed based on SEM observations to quantitatively describe the morphology and size of the structural units (fibres) of the shell secondary layer, the thickness of the primary layer, and the density and size of endopunctae of modern brachiopod shells; 3) new measurement methods were developed to describe the structural units (laminae and fibres) of fossil brachiopod shells; 4) statistical analyses of the acquired data were performed, i.e. independent-sample t-tests, frequency distribution plots, principal component analysis, and symmetric and asymmetric variants analyses; 5) stable isotope compositions (δ13C and δ18O) were tested from the secondary shell layer along shell ontogenetic increments in both dorsal and ventral valves of modern brachiopod shells; and 6) Transmission Electron Microscope (TEM) and Electron Backscatter Diffraction (EBSD) were performed in collaboration with other researchers to investigate the micro- and nanoscale features of modern brachiopod shells. Through these approaches, details of microstructural patterns were described and compared of twenty-nine specimens of six recent brachiopod species [Notosaria nigricans (Sowerby, 1846), Liothyrella neozelanica (Thomson, 1918), Liothyrella uva (Broderip, 1833), Magasella sanguinea (Leach, 1814), Gryphus vitreus (Born, 1778), Calloria inconspicua (Sowerby, 1846)] from different environmental conditions. Based on the morphology and size of the shell secondary layer fibres, the following conclusions were reached: 1) There was no significant difference in the shape and size of the fibres between ventral and dorsal valves of the same specimen; 2) An ontogenetic trend in the morphology of the fibres was found, as they become larger, wider, and flatter with increasing age. This change in size and shape indicated that the animal produced a fibrous layer with a different organic content during the ontogeny. 3) The relationship between size and shape of fibres and environmental conditions was clear when comparing two species of the same genus (L. neozelanica, L. uva) living in seawater with different carbonate saturation state and temperature, i.e. the fibres of L. uva are narrower and rounder than those of L. neozelanica. This in turn indicated a higher shell organic content in L. uva. Additional investigations were performed on the species Magellania venosa (Dixon, 1789), grown in the natural environment and in controlled culturing experiments in different pH conditions (7.35 to 8.15 ±0.05), and led to following conclusions: 1) Under low pH conditions, M. venosa produced a more organic-rich shell with larger and higher density endopunctae, and smaller secondary layer fibres, when subjected to about one year of culturing. 2) Increasingly negative δ13C and δ18O values were recorded by the shell produced during culturing and are related to the CO2–source in the culture setup. 3) Both the microstructural changes and the stable isotope results supported the value of brachiopods as robust archives of proxies for studying ocean acidification events in the geologic past. Finally, the measurements made on the size of structural units (laminae/fibres) of Cambrian to Devonian fossil brachiopod shells coupled with very detailed qualitative micro-scale observations, allowed the following conclusion: 1) The fossil organocarbonate brachiopod shells produced two main secondary layer fabrics: a laminar fabric in the Strophomenata, and a fibrous fabric in the Rhynchonellata. The Strophomenata laminar fabric shells appeared to be more variable and complex in their structural organization, but the thickness of the laminae was rather uniform and much thinner than that of the fibres. The Rhynchonellata fibrous fabric was more simple and uniform in its organization, but the size of the fibres was much more variable and comparable to the fabric of modern brachiopods. 2) Brachiopods with a fibrous secondary layer were mostly associated with biconvex shells, whereas brachiopods with a laminar secondary layer are associated with a variety of shell shapes. 3) Detailed microstructural studies were shown to be a very useful tool to construct the phylogenetic tree of the Phylum Brachiopoda. For example, the recorded gradual change in thickness of laminae from Billingselloidea to Productida could be important evidence to support the hypothesis that taxa with laminar microstructure diverged from the Billingsellida. Microstructural observation on the Chonetidina suggested that their shells had already evolved a laminar fabric during the Devonian. In summary, this new multidisciplinary and quantitative approach to describe the microstructure of brachiopod shells is a powerful tool to interpret microstructural variations of brachiopod shells in different ontogenetic stages and environmental conditions. Moreover, using the microstructure of brachiopod shells as a biomineral archive is a very promising tool for studying climate and environmental change and reconstructing the state of the oceans over the long history of geological time, and may be used to constrain the evolutionary history of the Phylum Brachiopoda.

APA, Harvard, Vancouver, ISO, and other styles

38

Joubin, Louis. "Recherches sur l'anatomie des brachiopodes inarticulés." Paris : Bibliothèque universitaire Pierre et Marie Curie (BUPMC), 2009. http://jubil.upmc.fr/sdx/pl/toc.xsp?id=TH_000327_001&fmt=upmc&idtoc=TH_000327_001-pleadetoc&base=fa.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Stern, Benjamin. "Biomineral lipids in living and fossil molluscs." Thesis, University of Newcastle Upon Tyne, 1996. http://hdl.handle.net/10443/1713.

Full text

Abstract:

It has been proposed that geochemical and biomolecular palaeontological information can be obtained from biomineral associatedli pids. The location of lipidic material within the inorganic structureo f molluscan shells has previously been unknown, with important implications for long term survival of lipids and post-depositional contamination from the environment. Discrete experimental stages have been investigated and the different mechanical and chemical methods combined for the removal of contaminating material prior to the release and analysis of surficial, intercrystalline and intracrystalline lipids. Three extraction protocols have been compared using Recent Patella vulgata shells. Sequential stages of cleaning and extraction treatments identify n-alkanes, cholesterol (free and bound) and bound fatty acids. The n-alkanes are indigenous to the shell, but laboratory contamination can be significant, and highlights the need for experimental blanks. Bound fatty acids are extracted from intercrystalline and intracrystalline fractions. Cholesterol is extracted throughout the sequential methodology. The extraction of these compounds after extensive cleaning treatments illustrates the protective role of the inorganic biomineral. An experimental protocol for sequentially extracting protected lipids from the shells of Recent molluscs has been tested to distinguish the indigenous shell lipids from laboratory contamination and postdepositional ingress. The use of a calcium carbonate blank reveals the phthalate plasticisers extracted from the shells are due to laboratory contamination. Pristane, phytane and free fatty acids were rarely extracted which limits their use for interpretation. The n-alcohols, bound fatty acids, ß-hydroxy fatty acids, cholesterol and other steroids are extracted from the shells in higher yields than the calcium carbonate blanks and are considered indigenous to the shells. Multivariate statistical analysis is used to compare the distributions of bound fatty acids and steroids extracted from different shell locations with the reported fatty acids and steroids for the soft tissues of the same species. The reported values for the soft tissues were used to indicate the original shell lipid composition. The shells lack the unsaturated bound fatty acids reported in the soft tissues. The saturated bound fatty acids of Littorina littorea shells also differ in the carbon number distributions to the reported saturated fatty acids of the soft tissues. Surficial shell extracts are characterized by steroidal ketones, representing sterols which have been oxidised by the cleaning treatments used. The steroids from both intercrystalline and intracrystalline shell locations in Littorina littorea are most similar to the soft tissues. However, the intercrystalline steroids are different to the intracrystalline steroids which may indicate a different original composition. Potential Class level phylogenetic differences between the shells of Recent molluscs are revealed by their steroidal and bound saturated fatty acid compositions. The bivalves (n=3) have bound saturated fatty acids with a carbon number maximum of C16 whilst the gastropods (n=8) have a maximum of C16 or C18 and exhibit higher yields. ß-hydroxy fatty acids may indicate phylogenetic differences below the Class level for the Gastropoda. Principal component statistical analysis of the shell steroidal composition indicates differences at the Class level. Steroidal markers indicating the dietary intake have been found in the shells. The application of a methodology for the sequential extraction of lipids from molluscan shells has been used in a preliminary analysis of shell material for the presence of hydrocarbon pollutants. The shell nalkanes require comparison of carbon number distributions and yields with an experimental calcium carbonate blank to ensure indigeneity. Different n-alkane distributions within two Artica islandica shell samples are attributed to the different sampling locations. Differences between Patella vulgata and Littorina littorea shells from the same environment have also been observed, indicating different n-alkane uptake by different species. Polyaromatic hydrocarbons and sterane biomarkers reported to be present in the soft tissues of Patella vulgata exposed to the Braer oil spill have been searched for in the shells of an exposed sample. These compounds have not been detected. No increase in the shell n-alkane yields or similarity in carbon number distribution with the spilt oil is observed. This suggests no hydrocarbon incorporation or deputation pathway into the shell. Quaternary aged mollusc shells yield n-alkanes, n-alcohols, bound fatty acids and cholesterol. These have been extracted from both intercrystalline and intracrystal line locations within the shells. When compared with the extracts from Recent shells the yields of these lipids from fossil shells are significantly lower. The n-alkanes extracted from Quaternary shells are dominated by laboratory contamination, although some indigenous intracrystalline n-alkanes have been extracted. The bound fatty acids from intercrystalline sites within the fossils maintain their carbonn umber distribution but decreasein yields with increasinga ge; no diagenetic products were observed. The previously reported phylogenetic distinctions based on the bound fatty acids betweent he gastropodsa nd bivalves are maintainedf or fossils. However,t he information obtained from this analysis is limited by the small diversity of lipid distributions found in these fossil shells.

APA, Harvard, Vancouver, ISO, and other styles

40

Azmy, Karem. "Isotopic composition of Silurian brachiopods, implications for coeval seawater." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq20988.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Brown, Karen E. "Bimineralisation of the calcitic-shelled, inarticulated brachiopod, Neocrania anomala." Thesis, University of Glasgow, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244444.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Minkler, Heidi. "The brachiopod communities and systematic paleontology of Anticosti Island /." Columbus, Ohio : Ohio State University, 2003. http://hdl.handle.net/1811/6105.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Bornsäter, Mellbin Barbro. "Linguliform Brachiopods from the terminal Cambrain to lower Ordovician Tiñu section, Mexico." Thesis, Uppsala universitet, Paleobiologi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-88918.

Full text

Abstract:

Tiñuformationen i Oaxaca, Mexiko är den enda fossilförande enheten från undre paleozoikum mellan den Laurentiska plattformen i nordvästra Mexiko och de Gondwanska lagerföljderna i Sydamerika. Det har nyligen visats att Tiñusektionen är en koncentrerad passiv kantlagerföljd med Gondwanakaraktär. Formationen delas upp i två delar; Yudachica från översta kambrium, som vilar okonformt på mellanproterozoisk grund, och Río Salinas från undre ordovicium (tremadoc). Formationen har tidigare studerats med avseende på dess avsättningsmiljöer och det fossila innehållet av trilobiter och konodonter vilka båda ger utmärkt biostratigrafisk kontroll över formationen. Ungefär 1000 exemplar av Linguliforma brachiopoder från tolv kalkstenslager från Tiñuformationen har studerats. Detaljerade undersökningar om taxonomi och stratigrafisk distribution av taxa har utförts. Faunan omfattar nio acrotretida taxa och en ny siphonotretid art och ett fåtal lingulida fragment. De acrotretida och det siphonotretida taxa har beskrivits grundligt och klassificerats till släkte.
The Tiñu Formation of Oaxaca State (Mexico) is the only fossiliferous lower Palaeozoic unit between the Laurentian platform in northwest Mexico and the Gondwanan successions in Andean South America. It has recently been shown that the Tiñu section is a condensed passive margin succession with Gondwanan character. The formation is divided into two members, namely, the uppermost Cambrian Yudachica Member, which rests nonconformably on a middle Proterozoic basement, and the Lower Ordovician (Tremadoc) Río Salinas Member. The formation has been studied with respect to its depositional environments and its fossil content of trilobites and conodonts, both providing excellent biostratigraphical control for the formation. About 1000 specimens of Linguliform brachiopods of twelve limestone horizons of the Tiñu Formation have been studied. Detailed investigations on taxonomy and stratigraphic distribution of the taxa have been made. The fauna comprises nine acrotretid taxa, a new siphonotretid species and a few linguloid fragments. The acrotretid and siphonotretid taxa have been thoroughly describes and classified to genus.

APA, Harvard, Vancouver, ISO, and other styles

44

Hoel, Ole Andreas. "Diversity and Life Habits of Silurian Strophomenide Brachiopods of Gotland." Doctoral thesis, Uppsala University, Department of Earth Sciences, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4728.

Full text

Abstract:

The Superfamily Strophomenoidea is a very diverse group of brachiopods in the Early Palaeozoic. In the Silurian succession on Gotland, they are among the most easily identifiable, and commonly found fossils. However, there are few detailed studies of this group from Gotland, and no new strophomenide taxa have been described from this area since 1869. The life habits of strophomenides are also poorly understood, partly because their morphology differs greatly from that of living brachiopods.

The succession on Gotland yielded 27 species belonging to the Strophomenoidea, of which two species and two subspecies are new. The remaining species have been described earlier from Gotland or Great Britain. The most important group is the Leptaeninae, which occurs commonly throughout the entire succession on Gotland. Five species (one new), two new subspecies and two taxa treated under open nomenclature were found. Leptaena rhomboidalis and Lepidoleptaena poulseni were specialized for life in shallow water environments, retaining a large apical pedicle; the remaining leptaenines were ambitopic. The Furcitellininae is represented by three genera comprising six species, of which only one persisted into the Ludlow. All were ambitopic, except Pentlandina loveni, which was specialized for high-energy environments. Six species of “strophodontids” from Gotland, belonging to the Leptostrophidae, the Strophodontidae and the Shaleriidae, share a shallow-bodied, variably concavo-convex shell with costellate ornament. Mesoleptostrophia and Brachyprion (Brachyprion) were long-ranged and ecologically tolerant, while B. (Erinostrophia), Strophodonta and Shaleria had short ranges and were ecologically specialized. The two earliest known cementing strophomenides occur on Gotland, and their hitherto unknown dorsal valves have been identified: Liljevallia was found to belong to the Douvillinidae. The cementing Leptaenoidea silurica was found to be conspecific with the ambitopic Scamnomena rugata; it was able to live ambitopically if removed from the substrate. The thickened dorsal valves allow reconstruction of its lophophore.

APA, Harvard, Vancouver, ISO, and other styles

45

Bose, Rituparna. "EPIBIONTS ON BRACHIOPODS FROM THE DEVONIAN DUNDEE FORMATION OF OHIO." Bowling Green State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1155059386.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Trubovitz, Sarah. "Reconstructing the Great Ordovician Biodiversification Event through brachiopods of Oklahoma." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1461943954.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Winrow, Paul. "A review of Cambrian lingulate brachiopods of England and Wales." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/29417.

Full text

Abstract:

The taxonomy of Cambrian lingulate (phosphatic shelled) brachiopods from England and Wales are reviewed in detail for the first time in nearly a century. 37 linguliformean brachiopod species, assigned to 23 genera, are described; 19 taxa are recorded in open taxonomy. Giving provisional names, three new genera, Svenjaella, Alexellus and Kayleigha are erected and nine new species are described (Chapter 4). Detailed cladistic analysis supports previous reports that Acrotretidae is a paraphyletic grouping of brachiopods which gave rise to other families within the Acrotretoidea (Chapter 6). Curticiidae is identified as lying outside the Acrotretoidea. The remaining families are supported as valid taxonomic units, albeit with some potential minor revisions. A new Scaphelasmatidae-Ceratretidae clade is consistently recovered. Support for the previously proposed subfamilies Neotretinae and Linnarssoniinae is partially recovered. The preservation of polygonal imprints of epithelial cells in lingulate brachiopods is reviewed and supplemented by new data (Chapter 7). The imprints are confirmed as representing moulds of epithelial cells as they are best preserved in areas where the shell has been thickened, and are similar in size to cells recorded in Lingula, the closest living relative to the extinct acrotretoids. Analysis of the morphology and sizes of cell-moulds demonstrates that there is no consistent relationship between cell width and valve size, and that they are not a useful taxonomic character within this group. The distribution of lingulate brachiopods across the Iapetus region is analysed using a number of statistical measures (Chapter 8). Although lingulate brachiopods have traditionally been considered to be of little utility in assessing palaeobiogeography, this analysis shows a clear palaeobiogeographic signal where lingulate faunas are sufficiently diverse, reflecting the history of the Iapetus ocean and the relative separation of Laurentia and Baltica through the Cambrian and Ordovician and provides confirmatory evidence that Palaeozoic lingulates had long-lived planktotrophic larvae.

APA, Harvard, Vancouver, ISO, and other styles

48

Verna, V. "GUADALUPIAN BRACHIOPODS FROM TUNISIA AND TURKEY: SYSTEMATICS AND PALAEOBIOGEOGRAPHIC IMPLICATIONS." Doctoral thesis, Università degli Studi di Milano, 2011. http://hdl.handle.net/2434/152907.

Full text

Abstract:

In the present PhD Thesis two Guadalupian brachiopod faunas are described respectively from succession cropping out at Djebel Tebaga de Medenine, S Tunisia, and from the Guadalupian lower-middle part of the Pamuçak Formation at Çürük Dağ, Antalya (Turkey). The study is based on collection already available in Dipartimento di Scienze della Terra “A. Desio”, Milano and on material newly collected by the writer. The taxonomic study and description of the brachiopod collections, based on the observations of the macro- and micro- external and internal morphological features, with critical comparison with the available literature, has allowed the determinations of 1260 specimens at generic and specific level into 68 species (including the undetermined ones) and 42 genera; they belong to orders Productida, Orthotetida, Orthida, Rhynchonellida, Athyridida, Spiriferida and Terebratulida for the Tunisian fauna; to the orders Productida, Orthotetida, Orthida, Rhynchonellida, Athyridida, Spiriferida, Spiriferinida and Terebratulida for the Turkish fauna. Five new species and two new genera are identified and established and are in press in two publications (Verna et al. in press a, b). Several brachiopod taxa are revised and their diagnostic characters better identified in order to make their determination, up to now problematic, easier (i.e. Squamularia Gemmellaro, 1899 and Permophricodothyris Pavlova). In the course of this research, the Gemmellaro collection of brachiopods from Sosio, Sicily has been also revised in part. The stratigraphic range of the Tunisian brachiopods is consistent with the Wordian- early Capitanian age suggested by the associated fusulinids and conodonts which are the tools on which the Permian Time Scale is based, allowing the correlation of the International (Global) with the Tethyan regional scale, particularly for the Guadalupian part. The age of the Turkish brachiopods coming from the lower middle part of the Pamuçak Formation is mid-Roadian to Capitanian, based on conodonts, fusulinids and already published data (Angiolini et al. 2007). The brachiopod record at Çürük Dağ section (Turkey) has implications to understand the pattern of the end-Guadalupian biotic crisis which is here represented by highly diversified pre-crisis assemblages terminating rather abruptly and being followed by Lopingian brachiopod taxa which show a significantly lower biodiversity. The last part of this study consists of a palaeobiogeographic analysis based on the comparison of the brachiopod faunas from Tunisia and Turkey originally collected and studied by the writer, with coeval ones described in several publications in the recent and distant past coming from the successions of Sosio (Sicily), Oman, N Iran, Central Afghanistan, Karakorum, Salt Range, SE Thailand. This palaeobiogeographic analysis aims to test the palaeogeographic reconstructions, independently derived from palaeomagnetic data and to derive the possible dispersal pattern of the brachiopod genera during the Guadalupian. The methods used for this analysis are cluster analysis and principal coordinate analysis (PCO), based on the similarity indices of Jaccard and Simpson applied to a presence/absence data matrix (taxa per geographic areas) of the brachiopod genera coming from Tunisia, Turkey and the other faunal stations quoted above, using the software PAST (Hammer et al. 2001). The palaeobiogegraphic affinities of the analyzed faunal stations are in agreement with the Guadalupian palaeogeographic reconstruction based on palaeomagnetic data of Muttoni et al. (2009) and indicates a consistent degree of isolation of Tunisia and Sosio from the other regions and strong faunal links between Turkey and the Gondwanan margins, represented by Oman, Salt Range and S Thailand.

APA, Harvard, Vancouver, ISO, and other styles

49

Rodland, David Laurence. "Spatial variability in modern brachiopod assemblages: paleoecological and geochemical implications." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/27858.

Full text

Abstract:

An accurate understanding of global patterns through geologic time depends upon multi-scale analyses of spatial variation within narrow temporal intervals. This work investigates geochemical and paleoecological patterns in modern brachiopod faunas which may serve as analogues for ancient brachiopod assemblages. The paleoclimatic utility of delta18O in the phosphatic phase of lingulid brachiopod shells requires valve secretion in equilibrium with seawater, an assumption tested (and rejected) when analyzed at scales ranging from millimeters to kilometers. By contrast, biological encrustation of the brachiopod fauna of the Southeast Brazilian Bight shows strong sensitivity to microenvironmental conditions such as host identity, shape, and size, and may prove useful for studies of ancient planktonic productivity. Comparison of encrustation patterns on naturally occurring brachiopods and bivalves collected from the same sites, and occupying the same size range, demonstrates that the results of encrustation studies on modern bivalves cannot be directly applied to ancient brachiopods. However, careful comparisons may reveal patterns of epibiont selectivity and the impact of changes in the relative abundance of host shells through geologic time. Finally, neither epibiont abundance nor diversity increase with host age as indicated by dated brachiopod shells from the past 1000 years. These results suggest that the temporal resolution of epibiont assemblages matches their spatial resolution, and strengthen evidence for competition among encrusting taxa. By documenting geochemical and paleoecological variation within shells and across a continental shelf, this work demonstrates the importance of understanding spatial variation across all scales before interpreting trends through time.
Ph. D.

APA, Harvard, Vancouver, ISO, and other styles

50

Botquelen, Arnaud Gourvennec Rémy Loi Alfredo. "Impact des variations eustatiques sur les assemblages benthiques à brachiopodes l'Ordovicien sarde et le Dévonien Ibéro-armoricain. Paléoécologie, Taphonomie, Statigraphie séquentielle, Systématique /." [S.l.] : [s.n.], 2003. http://tel.ccsd.cnrs.fr/docs/00/04/74/68/PDF/tel-00007779.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Brachiopoda'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles