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Les microfossiles du Jurassique superieur de Magnuszew (Pologne)

100%

Gorka H.

Acta Palaeontologica Polonica

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1965

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tom 10

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nr 3

Sont décrits les microfossiles des sédiments marins du Jurassique supérieur, extraits du sondage à Magnuszew et appartenant aux groupes suivants: les Dinoflagellés, les Acritarches, les microfossiles incertae sedis et les Algues sédentaires. Les Dinoflagellés appartiennent à 12 espèces, parmi lesquelles ont été distingués 2 nouveaux genres: Tetrasphaera n.gen, et Palaeosphaerium n.gen., ainsi que 5 nouvelles espèces: Palaeoperidinium nuciformoides n.sp., P. rhomboidalis n.sp., Hystrichosphaeridium polonicum n.sp., Tetrasphaera rara n.sp. et Palaeosphaerium infrequens n.sp. Parmi les Acritarches on a distingué 4 espèces, et parmi les microfossiles incertae sedis - 3 espèces attribuées aux deux genres nouveaux; ce sont: Dictyochroa ovalis n.gen., n.sp., Alisum magnum n.gen., n.sp. et Alisum parvum n.sp. Sont décrits, en outre: un microfossile problématique, génériquement et spécifiquement indéterminable, ainsi que deux menues Algues, appartenant, probablement, aux Chlorophycées. Une liste de la répartition stratigraphique des microfossiles, se trouvant dans les échantillons examinés, est jointe au travail.

2

Problematic microfossils from calc-silicate rocks of the Owiesno amphibolites [Gory Sowie Gneissic Block, SW Poland] - Preliminary results

63%

Gunia T.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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1997

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tom 45

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nr 2-4

3

Chondrichthyan genus Lissodus from the Lower Carboniferous of Ireland

63%

Duncan M.

Acta Palaeontologica Polonica

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2004

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tom 49

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nr 3

A new record of the chondrichthyan hybodontoid genus Lissodus is presented from two localities within the Mississippian (Tournaisian) rocks of Ireland. Five morphotypes of the genus are described within each of which occurs morphological variance. Specimens recovered and described herein are from crinoidal limestones whose palaeoenvironments are interpreted as ranging from a moderately shallow high−energy carbonate shelf, to relatively deep off−shore. The richest fauna recovered from the high−energy carbonate shelf, contains all five morphotypes raising the possibility that they may have been derived from a single species of shark. A discussion on the relationship between the five morphotypes and other Carboniferous Lissodus teeth is offered and it is argued that although the morphotypes differ slightly from other Carboniferous Lissodus teeth, they may belong to a closely related species not formally named until additional evidence is obtained. A mouth reconstruction using the teeth recovered from the Lower Carboniferous of Ireland is proposed.

4

Autothecal morphs and dormancy in the camaroid graptolite Xenotheka

63%

Mierzejewski P.

Acta Palaeontologica Polonica

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2003

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tom 48

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nr 1

The camaroid graptolite Xenotheka klinostoma Eisenack, 1937 is described from the lower Llanvirn limestones of Gilbergabrottet, northern Öland, Sweden. Two distinct autothecal morphs are recognized: (1) normal morph (described for the first time), i.e. an autotheca with an unsculptured outer surface, devoid of both an outer lining and autothecal occlusion, and inhabited by an active zooid; and (2) sealed morph, i.e. an autotheca coated and occluded, provided with a sculptured outer lining made of a unique verrucose fabric, and inhabited by an inactive or dormant zooid. In addition, the existence of a hypothetical (3) unsealed morph or re−opened autotheca, devoid of an autothecal occlusion but provided with an outer lining, and inhabited by a reactivated zooid, is predicted. The sealed morphs may represent an adaptation which allowed their inhabitants to survive adverse conditions. The outer lining of Xenotheka is compared with a peculiar outer membrane found in the modern hemichordate Rhabdopleura, from the intertidal zone of Fiji, and with camaroid extracamaral tissue.

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Spore-like bodies in some Early Paleozoic acritarchs: clues to chlorococcalean affinities

51%

Kazmierczak J., Kremer B.

Acta Palaeontologica Polonica

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2009

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tom 54

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nr 3

541-551

We present discoveries of internal bodies in problematic Silurian and Devonian organic−walled microfossils classified traditionally as polygonomorph, acanthomorph, sphaeromorph, and herkomorph acritarchs. These bodies are comparable with reproductive structures (autoand/or aplanospores) of modern unicellular green algae (Chlorococcales). Our findings suggest that many of these microfossils may represent asexually reproducing (sporulating) vegetative cells of chlorococcalean algae. The presence of spore−like bodies in the studied acritarchs supports earlier suggestions, based on ultrastructural and biomarker studies, that some acritarchs can be affined with green algae.

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Burgess Shale-type microfossils from the middle Cambrian Kaili Formation, Guizhou Province, China

51%

Harvey T. H. P., Ortega-Hernandez J., Lin J.-P., Yuanlong Z., Butterfield N. J.

Acta Palaeontologica Polonica

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2012

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tom 57

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nr 2

Diverse carbonaceous microfossils, including exceptionally preserved remains of non−biomineralizing metazoans, are reported from a basal middle Cambrian interval of the Kaili Formation (Guizhou Province, China). The application of a gentle acid maceration technique complements previous palynological studies by revealing a larger size−class of acritarchs, a richer assemblage of filamentous microfossils, and a variety of previously unrecovered forms. Metazoan fossils include Wiwaxia sclerites and elements derived from biomineralizing taxa, including chancelloriids, brachiopods and hyolithids, in common with previously studied assemblages from the early and middle Cambrian of Canada. In addition, the Kaili Formation has yielded pterobranch remains and an assemblage of cuticle fragments representing “soft−bodied” worms, including a priapulid−like scalidophoran. Our results demonstrate the wide distribution and palaeobiological importance of microscopic “Burgess Shale−type” fossils, and provide insights into the limitations and potential of this largely untapped preservational mode.

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Neogene radiolarian biostratigraphy and faunal evolution rates in the eastern equatorial Pacific ODP Sites 845 and 1241

51%

Kamikuri S.-I., Motoyama I., Nishi H., Iwai M.

Acta Palaeontologica Polonica

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2009

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tom 54

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nr 4

Radiolarians from Sites 845 and 1241 in the eastern equatorial Pacific were examined in order to evaluate the role of paleoceanographic perturbations upon the general faunal evolutionary pattern of tropical planktonic organisms during the last 17 Ma. Radiolarian appearance and extinction rates indicate no periods of mass extinctions during the past 17 Ma. However, a relatively rapid replacement of the species in the radiolarian assemblages occurs near the middle–late Miocene boundary. This replacement event represents the gradual extinction of a number of radiolarian species and their gradual replacement by evolving new species. The modern equatorial circulation system was formed near the middle–late Miocene boundary due to the closure of the Indonesian seaway. The minor faunal turnover appears to be associated with the formation of the modern equatorial circulation system near the middle–late Miocene boundary. Diatom assemblages in the equatorial Pacific became more provincial in character after about 9 Ma. The appearance and extinction rates of planktic foraminifers were relatively high near the middle–late Miocene boundary, and those of calcareous nannoplankton reached high values in the early late Miocene in the equatorial Pacific Ocean. Thus, faunal evolution from the middle Miocene type to late Miocene types occurred first, being followed by floral evolution. The middle–late Miocene boundary is not a sharp boundary for planktonic microfossils, but marks a time of transition critical for faunal and floral evolution in both siliceous and calcareous microfossil assemblages in the equatorial Pacific Ocean.

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Early Carboniferous chondrichthyan Thrinacodus from Ireland, and a reconstruction of jaw apparatus

51%

Duncan M.

Acta Palaeontologica Polonica

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2003

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tom 48

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nr 1

Specimens of the microscopic teeth of the chondrichthyan genus Thrinacodus are described from Mississippian (Tournaisian) rocks of Ireland. They are from calcareous mudstones or crinoidal limestones whose palaeoenvironments are interpreted as ranging from near shore, shallow water through moderately shallow high energy carbonate shelf, to relatively deep off−shore. The richest fauna was recovered from the high−energy carbonate shelf, containing both asymmetrical and symmetrical teeth raising the possibility that they may have been derived from a single species of shark. The teeth are assigned to Thrinacodus incurvus (Newberry and Worthen, 1866), which is suggested to be a senior synonym of Thrinacodus ferox Turner, 1982. Presently the genus is known only from isolated teeth. The asymmetrical and symmetrical teeth are described as two morphotypes, ferox morphotype and nanus morphotype. Within the morphotypes, morphological variation occurs, especially within the ferox morphotype, allowing a number of possible reconstructions of the dentition of Thrinacodus incurvus to be presented as a basis for future debate.

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Early Miocene carpological material from the Czech part of the Zittau Basin

51%

Teodoridis V.

Acta Palaeobotanica

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2003

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tom 43

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nr 1

10

Skeletonized microfossils from the Lower-Middle Cambrian transition of the Cantabrian Mountains, Northern Spain

51%

Clausen S., Alvaro J. J.

Acta Palaeontologica Polonica

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2006

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tom 51

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nr 2

Two different assemblages of skeletonized microfossils are recorded in bioclastic shoals that cross the Lower–Middle Cambrian boundary in the Esla nappe, Cantabrian Mountains. The uppermost Lower Cambrian sedimentary rocks represent a ramp with ooid−bioclastic shoals that allowed development of protected archaeocyathan−microbial reefs. The shoals yield abundant debris of tube−shelled microfossils, such as hyoliths and hyolithelminths (Torellella), and trilobites. The overlying erosive unconformity marks the disappearance of archaeocyaths and the Iberian Lower–Middle Cambrian boundary. A different assemblage occurs in the overlying glauconitic limestone associated with development of widespread low−relief bioclastic shoals. Their lowermost part is rich in hyoliths, hexactinellid, and heteractinid sponge spicules (Eiffelia), chancelloriid sclerites (at least six form species of Allonnia, Archiasterella, and Chancelloria), cambroclaves (Parazhijinites), probable eoconchariids (Cantabria labyrinthica gen. et sp. nov.), sclerites of uncertain affinity (Holoplicatella margarita gen. et sp. nov.), echinoderm ossicles and trilobites. Although both bioclastic shoal complexes represent similar high−energy conditions, the unconformity at the Lower–Middle Cambrian boundary marks a drastic replacement of microfossil assemblages. This change may represent a real community replacement from hyolithelminth−phosphatic tubular shells to CES (chancelloriid−echinoderm−sponge) meadows. This replacement coincides with the immigration event based on trilobites previously reported across the boundary, although the partial information available from originally carbonate skeletons is also affected by taphonomic bias.

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Cambrian microfossils from glacial erratics of King George Island, Antarctica

51%

Wrona R.

Acta Palaeontologica Polonica

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2004

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tom 49

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nr 1

Limestone erratics in the Early Miocene glacio−marine Cape Melville Formation of King George Island, West Antarctica, have yielded Early and Middle Cambrian small skeletal fossils (SSF) accompanied by calcified cyanobacteria, archaeocyath and spiculate sponges, trilobites and echinoderms. The SSF assemblage comprises disarticulated sclerites of chancelloriids, halkieriids, tommotiids, lapworthellids, palaeoscolecids, hyolithelminths, lingulate brachiopods, helcionelloid molluscs, hyoliths, and bradoriids. All 24 described species are common to Antarctica and Australia. Most are recorded here from Antarctica for the first time, including Shetlandia multiplicata gen. et sp. nov. and two new species Byronia? bifida and Hadimopanella staurata. The lithological and fossil contents of the boulders are almost identical with autochthonous assemblages from the Shackleton Limestone in the Argentina Range and Transantarctic Mountains. Cambrian outcrops around the Weddell Sea are a plausible source of the erratics. The fauna is closely similar to that from the uppermost Botomian Wilkawillina Limestone in the Flinders Ranges and Parara Limestone on Yorke Peninsula, and Toyonian Wirrealpa and Aroona Creek Limestones in the Flinders Ranges, as well as the Ramsay Limestone on Yorke Peninsula, all in the Arrowie and Stansbury Basins of South Australia. These very similar faunal and facies successions for Antarctica and Australia strongly support their common biotic and sedimentary evolution on the same margin of a greater Gondwana supercontinent throughout the Early Cambrian.

Ograniczanie wyników

Les microfossiles du Jurassique superieur de Magnuszew (Pologne)

Problematic microfossils from calc-silicate rocks of the Owiesno amphibolites [Gory Sowie Gneissic Block, SW Poland] - Preliminary results

Chondrichthyan genus Lissodus from the Lower Carboniferous of Ireland

Autothecal morphs and dormancy in the camaroid graptolite Xenotheka

Spore-like bodies in some Early Paleozoic acritarchs: clues to chlorococcalean affinities

Burgess Shale-type microfossils from the middle Cambrian Kaili Formation, Guizhou Province, China

Neogene radiolarian biostratigraphy and faunal evolution rates in the eastern equatorial Pacific ODP Sites 845 and 1241

Early Carboniferous chondrichthyan Thrinacodus from Ireland, and a reconstruction of jaw apparatus

Early Miocene carpological material from the Czech part of the Zittau Basin

Skeletonized microfossils from the Lower-Middle Cambrian transition of the Cantabrian Mountains, Northern Spain

Cambrian microfossils from glacial erratics of King George Island, Antarctica