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Dinosaurs evolved from archosaurs with this hip arrangement. The hip sockets faced downwards and the knobs on the femurs were in line with the femur. This "pillar-erect" arrangement appears to have evolved independently in various archosaur lineages, for example it was common in "Rauisuchia" (non-crocodylomorph paracrocodylomorphs ) and also ...
Bones from other parts of the body were found in 2009 and 2010. Five tracks made by a three-toed archosaur – presumably a theropod dinosaur – were found in rocks that were 1 metre (3.3 ft) above the layer where Smok was found. The footprints may belong to Smok, but the lack of foot bones in the skeleton make this association uncertain. [1]
Evidence from the study of skull bones of immature specimens of Daspletosaurus from the Dinosaur Park Formation (Alberta, Canada), indicating that skull material of Daspletosaurus and Gorgosaurus can be confidently identified regardless of ontogenetic stage of the specimens, is presented by Coppock et al. (2024). [188]
The mandible consists of both endochondral bones, which ossified from the Meckelian cartilage, and dermal bones. [5] In dinosaurs, only the dentary bears teeth. [25]: 40 mandibular fenestra The external mandibular fenestra is an opening in the lower jaw between the dentary, surangular, and angular bones. It is characteristic for archosauriforms ...
Rauisuchians are a category of archosaurs within a larger group called Pseudosuchia, which encompasses all archosaurs more closely related to crocodilians than to birds and other dinosaurs. First named in the 1940s, Rauisuchia was a name exclusive to Triassic archosaurs which were generally large (often 4 to 6 metres (13 to 20 ft)), carnivorous ...
Dinosaur bones often contain lines of arrested growth (LAGs), formed by alternating periods of slow and fast growth; in fact many studies count growth rings to estimate the ages of dinosaurs. [ 55 ] [ 56 ] The formation of growth rings is usually driven by seasonal changes in temperature, and this seasonal influence has sometimes been regarded ...
Fragment of long bone of a dinosaur is described from the Upper Cretaceous (Santonian–Campanian) sediments near the village of Izhberda (Orenburg Oblast, Russia) by Skutschas et al. (2022), who interpret the histological features of this bone as indicative of rapid continuous growth known in large-sized dinosaurs, and interpret this finding ...
A study on the duration of Late Cretaceous megaherbivore dinosaur assemblage zones in the 100 m thick stratigraphic section exposed at Dinosaur Provincial Park (Alberta, Canada) is published by Eberth et al. (2023), who interpret their findings as indicating that the dinosaur assemblage zones in the studied section had duration time of ~600 ...