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Wyszukujesz frazę "tyrannosaurid" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Skull structure and evolution in tyrannosaurid dinosaurs
Autorzy:
Currie, P J
Hurum, J.H.
Sabath, K.
Powiązania:
https://bibliotekanauki.pl/articles/22810.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
parsimonious analysis
phylogenesis
Coelurosauria
Tyrannosauridae
Theropoda
Dinosauria
skull structure
evolution
dinosaur
paleontology
tyrannosaurid dinosaur
Opis:
Tyrannosauridae can be subdivided into two distinct subfamilies—the Albertosaurinae and the Tyrannosaurinae. Previously recognized subdivisions Aublysodontinae and Shanshanosaurinae are rejected because they are based on insufficient material and juvenile specimens. Our results are based upon a phylogenetic analysis using PAUP program (Swofford 1999) of 77 skull characters and seven genera (Albertosaurus, Alioramus, Daspletosaurus, Gorgosaurus, Nanotyrannus, Tarbosaurus, and Tyrannosaurus); with Allosaurus as outgroup. Of the 77 characters used, more than half were parsimony informative. Asingle most parsimonious tree was obtained with the Tree Length being 88. The analysis of cranial characters and comparison of postcranial features reveal that Tarbosaurus bataar is not the sister taxon of Tyrannosaurus rex (contra Holtz 2001). Their similarities are partially due to the fact that both are extremely large animals. Thus, Tarbosaurus should be considered a genus distinct from Tyrannosaurus.
Źródło:
Acta Palaeontologica Polonica; 2003, 48, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada
Autorzy:
Currie, P J
Powiązania:
https://bibliotekanauki.pl/articles/20676.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Late Cretaceous
Cretaceous
Canada
Theropoda
dinosaur
Alberta
Saurischia
Coelurosauria
anatomy
Dinosauria
Tyrannosauridae
skull
paleontology
tyrannosaurid dinosaur
Opis:
Beautifully preserved, nearly complete theropod skeletons from Alberta (Canada) allow re−evaluation of the taxonomic status of North American tyrannosaurids. It is concluded that the most parsimonious interpretation of relationships leads to the separation of the two species of Albertosaurus(sensu Russell 1970) into Gorgosaurus libratusfrom the Campanian Dinosaur Park Formation and Albertosaurus sarcophagus from the upper Campanian/lower Maastrichtian Horseshoe Canyon Formation. Albertosaurus and Gorgosaurus are closely related, but can be distinguished from each other by more characters than are known to justify generic distinction within another tyrannosaurid clade that includes Daspletosaurus, Tarbosaurus and Tyrannosaurus. Daspletosaurus is known from multiple species that cover extensive geographic, ecological and temporal ranges, and it is sensible to maintain its generic distinction from Tyrannosaurus. All tyrannosaurid species have consistent ontogenetic trends. However, one needs to be cautious in assessing ontogenetic stage because many characters are size−dependent rather than age−dependent. There are relatively few osteological differences that can distinguish tyrannosaurid species at any age. For example, Nanotyrannus lancensis is probably a distinct species from Tyrannosaurus rex because there is no evidence of ontogenetic reduction of tooth counts in any other tyrannosaurid species. Some characters that are good for separating mature tyrannosaurids, such as differences in the sizes and shapes of maxillary fenestrae, are not useful for identifying the species of juveniles.
Źródło:
Acta Palaeontologica Polonica; 2003, 48, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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