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Wyszukujesz frazę "Makovicky, P.J." wg kryterium: Autor


Wyświetlanie 1-2 z 2
Tytuł:
The teeth of the unenlagiine theropod Buitreraptor from the Cretaceous of Patagonia, Argentina, and the unusual dentition of the Gondwanan dromaeosaurids
Autorzy:
Gianechini, F.A.
Makovicky, P.J.
Apesteguia, S.
Powiązania:
https://bibliotekanauki.pl/articles/20408.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
tooth
unenlagiine theropod
theropod
Buitreraptor
Cretaceous
Patagonia
Argentina
dentition
Gondwanan dromaeosaurid
dromaeosaurid
Theropoda
Dromaeosauridae
Unenlagiinae
Dinosauria
paleontology
dinisaur tooth
Opis:
The Unenlagiinae is a clade of Gondwanan dromaeosaurid theropods mainly known from incomplete skeletal material. The group includes two recently discovered theropods, Buitreraptor and Austroraptor, from which cranial remains are available with in situ maxillary and dentary teeth, thus allowing the study of tooth morphology. Among the derived traits that diagnose the dentition of unenlagiines are: (i) high tooth count, (ii) small size of individual teeth when compared with skull height, (iii) absence of denticles and carinae, and (iv) presence of longitudinal grooves on the tooth crown. This suite of dental characteristics, shared between Buitreraptor and Austroraptor, can be considered as diagnostic of the Unenlagiinae or, at least, a more exclusive clade within the group. The teeth of Buitreraptor exhibit a remarkable labiolingual compression, whereas Austroraptor possesses more conical teeth, probably respective autapomorphic features. On one hand, these dental morphologies differ from those observed in most Laurasian dromaeosaurids and, for instance, could be considered as further proof of the purported vicariant evolution of the lineage on the southern continents. On the other hand, the morphological similarities (e.g., absence of denticles) between the teeth of unenlagiines and other theropod lineages, including Mesozoic birds and ornithomimosaurs, can be considered as the result of parallel trends related to dental reduction.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theropod teeth from the upper Maastrichtian Hell Creek Formation “Sue” Quarry: New morphotypes and faunal comparisons
Autorzy:
Gates, T.A.
Zanno, L.E.
Makovicky, P.J.
Powiązania:
https://bibliotekanauki.pl/articles/945614.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
theropod
tooth
Upper Maastrichtian
Maastrichtian
Hell Creek Formation
morphotype
Dinosauria
morphometry
paleoecology
Cretaceous
North America
Opis:
Isolated teeth from vertebrate microfossil localities often provide unique information on the biodiversity of ancient ecosystems that might otherwise remain unrecognized. Microfossil sampling is a particularly valuable tool for documenting taxa that are poorly represented in macrofossil surveys due to small body size, fragile skeletal structure, or relatively low ecosystem abundance. Because biodiversity patterns in the late Maastrichtian of North American are the primary data for a broad array of studies regarding non-avian dinosaur extinction in the terminal Cretaceous, intensive sampling on multiple scales is critical to understanding the nature of this event. We address theropod biodiversity in the Maastrichtian by examining teeth collected from the Hell Creek Formation locality that yielded FMNH PR 2081 (the Tyrannosaurus rex specimen “Sue”). Eight morphotypes (three previously undocumented) are identified in the sample, representing Tyrannosauridae, Dromaeosauridae, Troodontidae, and Avialae. Noticeably absent are teeth attributed to the morphotypes Richardoestesia and Paronychodon. Morphometric comparison to dromaeosaurid teeth from multiple Hell Creek and Lance formations microsites reveals two unique dromaeosaurid morphotypes bearing finer distal denticles than present on teeth of similar size, and also differences in crown shape in at least one of these. These findings suggest more dromaeosaurid taxa, and a higher Maastrichtian biodiversity, than previously appreciated.
Źródło:
Acta Palaeontologica Polonica; 2015, 60, 1; 131-139
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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