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Wyszukujesz frazę "Lucas, S. G." wg kryterium: Autor


Wyświetlanie 1-4 z 4
Tytuł:
Age and correlation of Late Triassic tetrapods from southern Poland
Autorzy:
Lucas, S. G.
Powiązania:
https://bibliotekanauki.pl/articles/191907.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
Late Triassic
Polska
land-vertebrate faunachron
Krasiejów level
Lisowice level
Adamanian
Revueltian
Opis:
Age assignments of Triassic tetrapod fossils can be achieved by direct reference to a scheme of Triassic land-vertebrate faunachrons (LVFs) that correlates Triassic tetrapod fossil assemblages to each other based solely on the tetrapod fossils. Correlation of Triassic tetrapod assemblages to the standard global chronostratigraphic scale (SGCS, the “marine timescale”) is a separate cross correlation between the vertebrate biochronology and marine biochronology that usually relies on other data (e. g., palynostratigraphy, magnetostratigraphy, radioisotopic ages) to be completed. Late Triassic tetrapod fossils in southern Poland are found at two stratigraphic positions, the Krasiejów and Lisowice levels. The tetrapod assemblage of the Krasiejów level is assigned to the early Adamanian LVF based primarily on the stratigraphic overlap of the phytosaur Parasuchus with the Adamanian index aetosaur Stagonolepis. The amphibians Cyclotosaurus and Gerrothorax, a Proterochersis-like turtle and the aetosaur Paratypothorax from the Lisowice level indicate it is assignable to the Revueltian LVF. Cross correlations to the SGCS are less definitive, but suggest that the Krasiejów level is late Carnian and the Lisowice level is early/middle Norian. However, this correlation of the Krasiejów level is confounded by disagreements over correlation of the marine Carnian–Norian boundary to nonmarine strata. Indeed, the possibility that the Krasiejów tetrapods fill a gap in the early Norian record of tetrapods merits consideration. Such difficulties emphasize the value of correlating tetrapod assemblages to each other using a land-vertebrate biostratigraphy/biochronology, instead of immediately attempting the more problematic correlation to the SGCS.
Źródło:
Annales Societatis Geologorum Poloniae; 2015, 85, 4; 627-635
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cynodont teeth from the Carnian [Late Triassic] of Northern Italy
Autorzy:
Renesto, S
Lucas, S.G.
Powiązania:
https://bibliotekanauki.pl/articles/21889.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
cynodont
Carnian
Late Triassic
Italy
Gorno Formation
morphology
tooth
cynodont tooth
Opis:
A jaw fragment with three teeth preserved, collected from the Gorno Formation (Carnian, Upper Triassic) of Lombardy (Italy) is described. The teeth are transversely elongated, threecusped and bear anterior and posterior cingula. Their overall morphology supports their identification as postcanines of a “eucynodontian”. The unique tooth morphology of the new specimen supports its attribution to a new genus and species, while at the same time precluding positive assignment to already known gomphodont families. There is a fairly small record of gomphodont cynodonts in Europe, so that the described specimen adds to the knowledge of the distribution and diversity of European gomphodonts and it also represents the first ever collected in Italy.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 2; 357-360
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A revision of Campyloprion Eastman, 1902 (Chondrichthyes, Helicoprionidae), including new occurrences from the Upper Pennsylvanian of New Mexico and Texas, USA
Autorzy:
Itano, W. M.
Lucas, S. G.
Powiązania:
https://bibliotekanauki.pl/articles/139067.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
carboniferous
permian
eugeneodontiformes
helicoprionidae
edestoidea
Chondrichthyes
geometric morphometrics
karbon
perm
ryby chrzęstnoszkieletowe
ryby chrzęstne
chrzęstniki
morfometria geometryczna
Opis:
Campyloprion Eastman, 1902 is a chondrichthyan having an arched symphyseal tooth whorl similar to that of Helicoprion Karpinsky, 1899, but less tightly coiled. The holotype of Campyloprion annectans Eastman, 1902, the type species of Campyloprion, is of unknown provenance, but is presumed to be from the Pennsylvanian of North America. Campyloprion ivanovi (Karpinsky, 1922) has been described from the Gzhelian of Russia. A partial symphyseal tooth whorl, designated as Campyloprion cf. C. ivanovi, is reported from the Missourian Tinajas Member of the Atrasado Formation of Socorro County, New Mexico, USA. Partial tooth whorls from the Virgilian Finis Shale and Jacksboro Limestone Members of the Graham Formation of northern Texas, USA, are designated as Campyloprion sp. Two partial tooth whorls from the Gzhelian of Russia that were previously referred to C. ivanovi are designated as Campyloprion cf. C. annectans. The age of Toxoprion lecontei (Dean, 1898), from Nevada, USA, is corrected from the Carboniferous to the early Permian. An alternative interpretation of the holotype of T. lecontei is presented, resulting in a reversal of its anterior-to-posterior orientation. The genera Helicoprion, Campyloprion, and Shaktauites Tchuvashov, 2001 can be distinguished by their different spiral angles.
Źródło:
Acta Geologica Polonica; 2018, 68, 3; 403-419
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New data on the anatomy and relationships of the Paleocene crocodylian Akanthosuchus langstoni
Autorzy:
Hill, R.V.
Lucas, S.G.
Powiązania:
https://bibliotekanauki.pl/articles/20775.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Akanthosuchus langstoni
Alligatoroidea
Crocodylia
holotype
Paleocene
anatomy
dwarfism
paleontology
phylogenetic relationship
phylogenetic analysis
Opis:
The phylogenetic relationships of the Paleocene crocodylian Akanthosuchus langstoni are assessed using published data matrices and morphological data from the holotype and referred specimens. Cladistic analyses indicate that Akanthosuchus is unequivocally nested within Alligatoroidea. Weak support from a majority rule consensus tree indicates that Akanthosuchus may be more closely allied with alligatorines than with caimanines, but in the strict consensus tree these relationships remain ambiguous. There is no evidence from phylogenetic analyses to support the hypothesis that Akanthosuchus represents the postcrania of the Paleocene crocodylians Navajosuchus or Ceratosuchus. Growth marks observed in histological sections of osteoderms of the holotype of Akanthosuchus langstoni indicate that it was at least eight years old at the time of death. Although the individual may not have been fully mature at the time of death, lineage dwarfism cannot be ruled out as a possible reason for its relatively small size.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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