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Wyszukujesz frazę "Maastrichtian" wg kryterium: Temat


Wyświetlanie 1-9 z 9
Tytuł:
The Belemnitella stratigraphy of the Upper Campanian : basal Maastrichtian of the Middle Vistula section, central Poland
Autorzy:
Remin, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2059997.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Campanian
Maastrichtian
Vistula section
belemnites
biostratigraphy
artificial Neural Networks
Campanian-Maastrichtian boundary
Opis:
This taxonomy and stratigraphy of the Upper Campanian and Lower Maastrichtian Belemnitella lineages, from the Middle Vistula sections, based on new collections, is presented. The correlation to the basal Maastrichtian standard GSSP at Tercis, France, is provided based on inoceramid bivalve stratigraphy. The Artificial Neural Networks (ANN), particularly the self-organizing Kohonen algorithm, was applied to taxonomic discrimination. Eight morphotypes within the genus Belemnitella, understood here as natural species populations, were recognised. Five of these are assigned to known taxa: Belemnitella mucronata, B. posterior, B. minor [= B. minor I and B. minor II], B. langei and B. najdini; and three, B. sp. a, B. sp. 1 and B. sp. 2, are left in open nomenclature. Four Belemnitella zones are proposed. Due to its palaeogeographic position, between Western and Eastern Europe, the Middle Vistula section is characterized by the co-occurrence of Belemnitella species from those two areas. Consequently, it enables better correlation of Belemnitella-based schemes; the East European B. najdini and B. posterior are placed next to West European B. minor chronospecies I and II. The Campanian/Maastrichtian boundary, as currently defined, is placed at the top of the najdini – posterior Zone, which is an equivalent of the Belemnella-based boundary, i.e. at the base of the Belemnella obtusa / Belemnella vistulensis zones. Within the top of the najdini – posterior Zone occurs a level (an interval of only a few metres), where nearly all of the Upper Campanian Belemnitella disappear. This level coincides with taxonomic changes observed within the co-occurring representatives of genus Belemnella.
Źródło:
Geological Quarterly; 2015, 59, 4; 783--813
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Upper Campanian - lower Maastrichtian cephalopod fauna of Botellos, Nuevo León: a key to understand faunal turnover across the Campanian-Maastrichtian boundary in NE Mexico
Autorzy:
Ifrim, C.
Lara de la Cerda, J. E.
Peña Ponce, V. H.
Stinnesbeck, W.
Powiązania:
https://bibliotekanauki.pl/articles/139296.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ammonoids
Campanian
Maastrichtian
Mexico
faunal turnover
amonity
kampan
mastrycht
Meksyk
Opis:
A new cephalopod collection from the Campanian-Maastrichtian boundary interval of NE Mexico, consisting of 1076 individuals assigned to 29 species and 22 genera is presented. This collection is a mix of ammonoids, one coleoid and one nautilid, which originate from at least three ammonoid biozones: The upper Campanian Exiteloceras jenneyi and Nostoceras (Nostoceras) hyatti zones, and the lower Maastrichtian Pachydiscus (Pachydiscus) neubergicus Zone. The age of the collection is thus middle late Campanian to late early Maastrichtian, and it closes a stratigraphic gap between faunas described formerly from this region. The specimens are nuclei collected from the desert pavement. The abundance of specimens allows for a comparison to other Campanian-Maastrichtian ammonoid records from Mexico, North America and Europe.
Źródło:
Acta Geologica Polonica; 2017, 67, 1; 145-162
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Belemnella stratigraphy of the Campanian-Maastrichtian boundary; a new methodological and taxonomic approach
Autorzy:
Remin, Z.
Powiązania:
https://bibliotekanauki.pl/articles/138983.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
belemnity
biostratygrafia
kampan
Kronsmoor
mastrycht
sztuczne sieci neuronowe
Wisła
Artificial Neural Networks
belemnites
biostratigraphy
Campanian
Campanian-Maastrichtian boundary
Kronsmoor section
Maastrichtian
Vistula section
Opis:
The taxonomy and stratigraphy of the Upper Campanian and Lower Maastrichtian belemnites from the Vistula (central Poland) and Kronsmoor (northern Germany) sections are revised on the basis of new collections from the Vistula section as well as a reinvestigation of the classic collection of Schulz from the Kronsmoor section. For the taxonomic description a new biometric procedure is proposed, which can be applied to both the genera Belemnella and Belemnitella. For the species-level taxa recognition the Artificial Neural Networks method, the self-organizing Kohonen algorithm, was implemented. This new taxonomic and methodological approach enabled the recognition of nine species of the genus Belemnella. Five of them can be assigned to the existing species B. lanceolata, B. longissima, B. inflata, B. obtusa and B. vistulensis. However, the species concept differs from that applied by Schulz (1979). As a consequence, the stratigraphic ranges of these species are modified. Four species are left in open nomenclature and represent possibly new species. Future studies may reveal that they might be assigned to East European forms from Ukraine or Russia. The species of Belemnella recognized are placed into the stratigraphic framework based on the standard ammonite and inoceramid bivalve zonations, especially those recognized in the Vistula section. The newly proposed belemnite zonation for the Vistula and Kronsmoor sections is correlated via inoceramids with the standard GSSP at Tercis, France, in order to identify the base of the Maastrichtian Stage. The Campanian/Maastrichtian boundary as defined in Tercis is placed here at the base of the newly defined B. obtusa and B. vistulensis Zones ["obtusa/vistulensis"] - thus it is markedly higher than the traditional boundary based on the FAD of representatives of the genus Belemnella - This new boundary coincides well with a distinct turnover of belemnite guard morphology and represents one of the most important points in the early evolutionary history of Belemnella. Three belemnite zones defined by their lower boundaries are recognized in the Campanian/Maastrichtian interval, in addition to three subzones recognized within the B. obtusa Superzone. The B. lanceolata and B. inflata zones as understood here are referred to the Upper Campanian [Tercis definition]. The B. obtusa Zone is subdivided into three subzones, viz.: Belemenlla vistulensis, Belemnella sp. G and Belemnella sp. F, which are referred to the Lower Maastrichtian [Tercis definition]. The fast evolving species of Belemnella enable the proposal of a biostratigraphic scheme with a resolution that is higher than those based on inoceramid bivalves and ammonites - the longevity of a belemnite zone could be as low as 200Ky.
Źródło:
Acta Geologica Polonica; 2012, 62, 4; 495-533
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Latest Cretaceous leaf floras from southern Poland and western Ukraine
Autorzy:
Halamski, A.T.
Powiązania:
https://bibliotekanauki.pl/articles/21685.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Late Cretaceous
leaf flora
Angiospermae
Coniferae
Leptosporangiatae
Debeya
paleobotany
taxonomy
Campanian
Maastrichtian
Cretaceous
Polska
Ukraine
Opis:
Latest Cretaceous (Campanian to Maastrichtian) leaf fossil assemblages are described from 33 exposures ranging from the southern border of the Holy Cross Mountains (southern Poland) through the Roztocze region (south−eastern Poland) to the vicinity of L’viv (western Ukraine). The fossil assemblage is allochthonous, preserved in marine sediments, yet complete compound leaves strongly argue for the transport having been short. Krasnobród and Potelych (Potylicz) are the richest localities; both are late Campanian. The abundance of angiosperm remains in this period is explained by a marine lowstand resulting in nearby emergent vegetated areas. The flora was composed of ferns (three species), conifers (five species, including the commonest Geinitzia reichenbachii), dicotyledons (seventeen taxa; Debeya paulinae sp. nov., two other species of Debeya, and Rarytkinia polonica being the most frequent), and a single presumed monocotyledon. The eudicot clade is formalised as supersubclass Eudicotyledoneae Doyle and Hotton ex Halamski, herein. The approximately equal abundance of serrate/lobate and entire−margined dicots attests to an intermediate character of the flora between more thermophilic and polar vegetation. The material may have come from at least two communities: xeromorphic mixed Debeya−conifer forests and platanoid−Lauraceae forests growing in disturbed environments along rivers. The assemblage is most similar to approximately coeval floras from Westphalia and the Netherlands.
Źródło:
Acta Palaeontologica Polonica; 2013, 58, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New elmisaurine specimens from North America and their relationship to the Mongolian Elmisaurus rarus
Autorzy:
Funston, G.F.
Currie, P.J.
Burns, M.E.
Powiązania:
https://bibliotekanauki.pl/articles/22633.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
new species
Elmisaurinae
Dinosauria
Oviraptorosauria
Caenagnathidae
Campanian
Maastrichtian
North America
relationship
Mongolia
Elmisaurus rarus
Opis:
New specimens from Canada confirm the presence of elmisaurines in North America and shed light on the relationship of Leptorhynchos elegans to Mongolian forms. These specimens have hindlimb elements previously unknown from elmisaurines in the Dinosaur Park Formation, including tibiae and pedal phalanges. Metatarsal anatomy is sufficiently different to merit a generic distinction from Elmisaurus rarus, and both can be distinguished from Caenagnathus collinsi and Chirostenotes pergracilis. Differences between these taxa include body size, degree of coossification of the tarsometatarsus, and development of cruciate ridges of the metatarsal III. Histological analysis confirms that these differences are not correlated with ontogenetic age of the specimens. The results support the informal separation of caenagnathids based on metatarsal structure, and allow comments on paleobiological differences between caenagnathids and oviraptorids.
Źródło:
Acta Palaeontologica Polonica; 2016, 61, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stratigraphically important ammonites from the Campanian-Maastrichtian boundary interval of the Middle Vistula River section, central Poland
Autorzy:
Machalski, M.
Powiązania:
https://bibliotekanauki.pl/articles/138963.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
amonit
kampan
mastrycht
stratygrafia
systematyka
Wisła
współzależność
ammonites
Campanian
correlation
Maastrichtian
Middle Vistula River section
stratigraphy
taxonomy
Opis:
The formal definition of the Global Stratotype Section and Point (GSSP) for the base of the Maastrichtian Stage at Tercis, southwest France, is based on the first or last occurrences of twelve taxa, including three species of ammonites, Pachydiscus (Pachydiscus) neubergicus, Diplomoceras cylindraceum, and Nostoceras (Nostoceras) hyatti. The taxonomy and stratigraphical distribution of these, and allied forms, are studied, on the basis of material from the opoka succession across the upper Campanian.lowermost Maastrichtian boundary in the Middle Vistula River section, central Poland. in view of the imprecise location of two ammonite GSSP markers in that section, a direct ammonite-based correlation with the GSSP at Tercis is impossible. however, data available indicate that in the Middle Vistula River section the first occurrence of Pachydiscus (P.) neubergicus and the last occurrence of Nostoceras (N.) hyatti are situated significantly higher than the first occurrence of Belemnella lanceolata, the traditional belemnite marker for the base of the Maastrichtian Stage in the Boreal Realm, and that Diplomoceras cylindraceum appears significantly below this level. There are no unequivocal records of Pachydiscus (P.) neubergicus from the Belemnella lanceolata Zone s.l. in the Middle Vistula River section.
Źródło:
Acta Geologica Polonica; 2012, 62, 1; 91-116
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theropod tooth assemblages from the Late Cretaceous Maevarano Formation and the possible presence of dromaeosaurids in Madagascar
Autorzy:
Fanti, F
Therrien, F.
Powiązania:
https://bibliotekanauki.pl/articles/20343.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
theropod diversity
Cretaceous
Late Cretaceous
dromaeosaurid
tooth
Maastrichtian
theropod tooth
paleobiogeography
Abelisauridae
Dinosauria
Madagascar
Campanian
paleontology
Dromaeosauridae
Maevarano Formation
Opis:
The latest Cretaceous (Campanian?–Maastrichtian) Maevarano Formation of the Mahajanga Basin, Madagascar, preserves one of the most diverse fossil vertebrate faunas of the Gondwanan landmasses. Over 180 isolated theropod teeth recovered from that formation were studied in order to document theropod diversity in the Madagascar insular setting. Tooth morphology and characteristics of the Maevarano teeth were compared to those of known theropod teeth for identification, including the Malagasy non−avian theropods Majungatholus atopus and Masiakasaurus knopfleri. Tooth and denticle morphologies permit the recognition of five tooth morphotypes: three morphotypes are referable to Majungatholus atopus based on variation in tooth morphology observed in teeth preserved in situ in the jaws of two specimens, and one morphotype is ascribable to Masiakasaurus knopfleri. Teeth pertaining to the fifth morphotype differ from other morphotypes in the size and orientation of the denticles, shape and orientation of blood grooves, and in general tooth morphology. Statistical analyses reveal that the fifth Maevarano tooth morphotype is similar to dromaeosaurid teeth, suggesting that a yet unknown theropod taxon inhabited Madagascar during the latest Cretaceous. This morphotype represents the first evidence of the possible presence of a dromaeosaurid in Madagascar and supports the theory that dromaeosaurids were present throughout Pangaea before the break−up of the supercontinent during the Late Jurassic and had colonized Madagascar before its separation from Africa during the Early Cretaceous.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New mammalian remains from the Late Cretaceous La Colonia Formation, Patagonia, Argentina
Autorzy:
Rougier, G W
Forasiepi, A.M.
Hill, R.V.
Novacek, M.
Powiązania:
https://bibliotekanauki.pl/articles/21844.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
mammalian remains
Late Cretaceous
La Colonia Formation
Patagonia
Argentina
mammal fauna
Los Alamitos
Coloniatherium cilinskii
Vincelestes
Mammalia
Mesungulatidae
Cretaceous
new remains
Campanian
Maastrichtian
Opis:
Knowledge of the latest Late Cretaceous mammalian fauna in the South America was, until now, mostly based on dentally known taxa recovered at Los Alamitos (Río Negro, Argentina). Here we describe new mammalian remains collected in outcrops of the La Colonia Formation (Campanian–Maastrichtian) exposed in Chubut Province, Argentina, warranting the recognition of a new mesungulatid: Coloniatherium cilinskii gen. et sp. nov. The mammalian high−level taxonomic compositions of the localities in the La Colonia Formation and at Los Alamitos are roughly similar (Reigitheriidae, Mesungulatidae, and Ferugliotheridae are represented in both localities), but gondwanatheriids and the more plesiomorphic dryolestoids from Los Alamitos are missing from La Colonia. The most abundant mammalian remains collected at La Colonia correspond to large−sized mesungulatids. Coloniatherium cilinskii is recognized by the dentition and lower jaw, and we assign five isolated petrosal bones, focusing our study primarily on the analysis of the ear regions. The morphology of the petrosals suggests a phylogenetic position similar to Vincelestes, but sharing some derived features, possibly convergent, with therians. Attribution of the petrosals to the mesungulatid Coloniatherium cilinskii is supported by overall morphology, size, and relative abundance among the mammalian remains from La Colonia.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 2; 195-212
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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