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Wyświetlanie 1-3 z 3
Tytuł:
Oviraptorosaur tail forms and functions
Autorzy:
Persons,IV, W.S.
Currie, P.J.
Norell, M.A.
Powiązania:
https://bibliotekanauki.pl/articles/945893.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Dinosauria
paleozoology
Theropoda
Oviraptorosauria
oviraptorosaur
pygostyle
caudal musculature
functional morphology
Opis:
Oviraptorosaur caudal osteology is unique among theropods and is characterized by posteriorly persistent and exceptionally wide transverse processes, anteroposteriorly short centra, and a high degree of flexibility across the pre-pygostyle vertebral series. Three-dimensional digital muscle reconstructions reveal that, while oviraptorosaur tails were reduced in length relative to the tails of other theropods, they were muscularly robust. Despite overall caudal length reduction, the relative size of the M. caudofemoralis in most oviraptorosaurs was comparable with those of other non-avian theropods. The discovery of a second Nomingia specimen with a pygostyle confirms that the fused terminal vertebrae of the type specimen were not an abnormality. New evidence shows that pygostyles were also present in the oviraptorosaurs Citipati and Conchoraptor. Based on the observed osteological morphology and inferred muscle morphology, along with the recognition that many members of the group probably sported broad tail-feather fans, it is postulated that oviraptorosaur tails were uniquely adapted to serve as dynamic intraspecific display structures. Similarities, including a reduced vertebral series and a terminal pygostyle, between the tails of oviraptorosaurs and the tails of theropods widely accepted as basal members of the Avialae, appear to be convergences.
Źródło:
Acta Palaeontologica Polonica; 2014, 59, 3; 553-567
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Allometric growth in the frontals of the Mongolian theropod dinosaur Tarbosaurus bataar
Autorzy:
Yun, C.-G.
Peters, G.F.
Currie, P.J.
Powiązania:
https://bibliotekanauki.pl/articles/31341395.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
allometric growth
frontal bone
growth change
Mongolia
dinosaur
theropod dinosaur
Tarbosaurus bataar
Dinosauria
Theropoda
Tyrannosauridae
Tyrannosaurus rex
ontogenesis
allometry
Źródło:
Acta Palaeontologica Polonica; 2022, 67, 3; 601-615
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variation in premaxillary tooth count and a developmental abnormality in a tyrannosaurid dinosaur
Autorzy:
Miyashita, T.
Tanke, D.H.
Currie, P.J.
Powiązania:
https://bibliotekanauki.pl/articles/23378.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
tooth variation
premaxillary tooth
tooth
developmental abnormality
tyrannosaurid dinosaur
Dinosauria
Theropoda
Tyrannosauridae
tooth count
developmental regulation
Dinosaur Park Formation
Alberta city
Canada
Opis:
Premaxillary tooth count tends to be stable amongst toothed dinosaurs, and most theropods have four teeth in each premaxilla. Only one case of bilaterally asymmetric variation is known in theropod premaxillary dentition, and there is no record of ontogenetic or individual variation in premaxillary tooth count. Based on these observations, a tyrannosaurid left premaxilla with three teeth (TMP 2007.20.124) is an interesting deviation and represents an unusual individual of Daspletosaurus sp. with a developmental abnormality. The lower number of teeth is coupled with relatively larger alveoli, each of which is capable of hosting a larger than normal tooth. This indicates that tooth size and dental count vary inversely, and instances of reduction in tooth count may arise from selection for increased tooth size. On the other hand, the conservative number of premaxillary teeth in most theropods implies strong developmental constraints and a functional trade−off between the dimensions of the premaxillary alveolar margin and the size of the teeth. In light of recent advances in the study of tooth morphogenesis, tooth count is a function of two parameters: dimensions of an odontogenic field for a tooth series, and dimensions of tooth positions. A probable developmental cause for the low tooth count of TMP 2007.20.124 is that the dimensions of the alveoli expanded by approximately a third during tooth morphogenesis. Numerical traits such as tooth count are difficult to treat in a phylogenetic analysis. When formulating a phylogenetic character, a potential alternative to simply counting is to rely on the morphological signature for developmental parameters that control the number of the element in question.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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