Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "Ceratopsia" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Femoral histology and growth patterns of the ceratopsian dinosaur Psittacosaurus sibiricus from the Early Cretaceous of Western Siberia
Autorzy:
Skutschas, P.P.
Morozov, S.S.
Averianov, A.O.
Leshchinskiy, S.V.
Ivantsov, S.V.
Fayngerts, A.V.
Feofanova, O.A.
Vladimirova, O.N.
Slobodin, D.A.
Tematy:
Dinosauria
Ceratopsia
Psittacosaurus
bone histology
Cretaceous
Siberia
Russia
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:
https://bibliotekanauki.pl/articles/2082328.pdf  Link otwiera się w nowym oknie
Opis:
The early ceratopsian dinosaur Psittacosaurus sibiricus from the Early Cretaceous of Western Siberia, Russia, is one of the most advanced and largest (up to 2.5 m) members of the genus. Here we present a description of ontogenetic changes in the long-bone histology of this species. Analysis of a growth series of femora demonstrates significant histological maturation during ontogeny, expressed by the progressive appearance of signs of bone remodeling (erosion bays, secondary bone formation), decreasing of vascularity, changing of the orientation of vascular canals from reticular to longitudinal, and appearance of parallel-fibred bone in the outer part cortex. These ontogenetic changes in the longbone histology of P. sibiricus are generally similar to those of another relatively advanced species, P. lujiatunensis from China. The basal P. mongoliensis from Mongolia shows less mature long-bone histology during late ontogeny (e.g., the late appearance of signs of remodeling and the predominance of reticular vascularization at later stages). We suggest that the earlier achievement of histological maturity is an evolutionary trend of the genus Psittacosaurus.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New protoceratopsid specimens improve the age correlation of the Upper Cretaceous Gobi Desert strata
Autorzy:
Czepiński, L.
Tematy:
Dinosauria
Ceratopsia
Protoceratopsidae
biostratigraphy
gradual evolution
anagenesis
Mesozoic
Mongolia
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:
https://bibliotekanauki.pl/articles/2082224.pdf  Link otwiera się w nowym oknie
Opis:
New protoceratopsid (Dinosauria: Ceratopsia) specimens from two Late Cretaceous Mongolian localities with problematic stratigraphy are described. A specimen of Protoceratops andrewsi from the Zamyn Khond locality enables its correlation with other sites of the Djadokhta Formation. P. andrewsi is also abundant in the Üüden Sair locality, variously assigned to the Djadokhta or Baruungoyot formations. However, one new specimen from that site exhibits a fused nasal horn and a sharp buccal crest of the dentary. With these apomorphic features, it resembles Bagaceratops rozhdestvenskyi, known from the Baruungoyot and Bayan Mandahu formations. It may be an evidence for: sympatric evolution of B. roz hdestvenskyi and P. andrewsi; a dispersal of Bagaceratops to Üüden Sair; hybridization between the two parapatric taxa; or the anagenetic evolutionary transition from P. andrewsi to Bagaceratops. The anagenetic explanation appears to be most strongly supported by given data. This new record advocates for the age of the sediments from the Üüden Sair locality being intermediate between the Djadokhta and Baruungoyot formations. The observed changes in the frequency of the apomorphic features within protoceratopsid samples from various Late Cretaceous sites of the Gobi Desert potentially enable their correlations and chronological ordering.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New data on cranial anatomy of the ceratopsian dinosaur Psittacosaurus major
Autorzy:
You, H -L
Tanoue, K.
Dodson, P.
Tematy:
dinosaur
Yixian Formation
Cretaceous
Dinosauria
paleontology
China
Ceratopsia
Psittacosaurus major
ceratopsian dinosaur
Liaoning
anatomy
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:
https://bibliotekanauki.pl/articles/20202.pdf  Link otwiera się w nowym oknie
Opis:
An exceptionally preserved skull and mandible of ceratopsian dinosaur Psittacosaurus major revealed many anatomical details such as the existence of an elliptical median interpremaxillary foramen, a prominent neurovascular canal on the internal wall of the beak, long, slightly divergent basipterygoid processes developed as vertical blades with a deep cleft between them, and horizontally oriented vomer. The new specimen shows two autapomorphies of Psittacosaurus major, the transversely narrow dorsal skull roof and very prominent dentary flanges, confirming the presence of two large−skulled psittacosaur species in the Lujiatun Bed of the Lower Cretaceous Yixian Formation in Beipiao City, western Liaoning Province, China, the longand narrow−skulled P. major, and broad−skulled P. lujiatunensis.
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

    Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies