Individual and Ontogenetic Variation in Theropod Dinosaur Teeth PDF Download

Author: Lisa Glynis Buckley
Publisher:
ISBN:
Category : Coelophysis
Languages : en
Pages : 218

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Author: Lisa G. Buckley
Publisher: New Mexico Museum of Natural History and Science
ISBN:
Category : Coelophysis
Languages : en
Pages : 80

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Author: Gavin Bradley
Publisher:
ISBN:
Category : Albertosaurus
Languages : en
Pages : 208

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The sparseness of the fossil record and the subjectivity of interpreting behaviour from morphological and taphonomic evidence have impeded studies on the behaviour of juvenile theropod dinosaurs. Most evidence for social behaviour in juvenile dinosaurs comes from multi individual bone beds or parent dinosaurs preserved while brooding on eggs or young. There is therefore a desire for alternative methods of assessing social behaviour, leading to the two key questions of this thesis: 1) can inferences about social behaviour be made using isolated specimens?, and 2) does gregariousness change with ontogeny in Gorgosaurus? A multidisciplinary study using isolated specimens of Gorgosaurus libratus, including a newly described juvenile specimen from Dinosaur Provincial Park in southern Alberta, was carried out in the hopes of answering these two questions. A review of social behaviour in modern animals suggests that gregariousness is gradational and varies from taxon to taxon, even within closely related groups such as Felidae. Inferences of social behaviour for dinosaurs based solely on phylogenetic bracketing is therefore not recommended. However, numerous analyses can be performed on isolated specimens in order to infer social behaviours including parental care, group living, sexual display and combat. For example, palaeopathologies may indicate intraspecific combat. Ontogenetic changes, such as growth curves, allometry of horns and crests, and changes in stable isotopes because of dietary changes may also indicate changing behavioural as well as ecological roles during development. Femoral circumferences are useful in inferring body mass of theropods, and in bone bed aggregations this can aid in studies of growth rates, which can inform social behaviour. Taphonomic damage can reduce sample sizes and make such studies problematic. Statistical analyses, however, suggest that three femoral-diameter-based estimation models may be used to predict femoral circumference measurements in tyrannosaurids. Ontogenetic morphological changes in Gorgosaurus may also inform inferences about social behaviour. Positive allometric growth of the lacrimal horns may imply a display function, as seen in modern bovid and cervid mammals. Slow maximum growth rates of juvenile Gorgosaurus, compared to other tyrannosaurids, calculated using lines of arrested growth and body mass estimations, may indicate social aggregation during early ontogeny in order to survive alongside faster growing and larger predators, such as Daspletosaurus or, alternatively, reduced growth due to nutritional stresses on juveniles. Macrowear patterns in the teeth of UALVP 49500 and UALVP 10, an adult specimen, exhibit four major types of tooth wear: enamel spalling, longitudinal facets, tip wear, and barrel-shaped puncture marks. Adult teeth were typified by tip wear, and juvenile teeth were typified by longitudinal wear facets. This is hypothesised to reflect a change in feeding behaviour during ontogeny, from shearing and slicing of meat, with high levels of tooth occlusion in the young, to the "puncture and pull" method previously hypothesized for adults. A slicing feeding method for juveniles is further supported by thinner teeth with higher denticle densities, smaller bite forces, and a more circular orbit shape that is less resistant to the strain of high bite forces on the skull. This multidisciplinary analysis shows that substantial ontogenetic change occurred in Gorgosaurus, and demonstrates that social behaviour may be inferred from isolated specimens. As well, a description of a juvenile Gorgosaurus libratus, UALVP 49500, presents the first examination of post cranial material in such a specimen, and supports a genus-level distinction between Albertosaurus sarcophagus and Gorgosaurus libratus.

Author: J. Michael Parrish
Publisher: Indiana University Press
ISBN: 0253009472
Category : Science
Languages : en
Pages : 313

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Drawn from a 2005 international symposium, these essays explore current tyrannosaurid current research and discoveries regarding Tyrannosaurus rex. The opening of an exhibit focused on “Jane,” a beautifully preserved tyrannosaur collected by the Burpee Museum of Natural History, was the occasion for an international symposium on tyrannosaur paleobiology. This volume, drawn from the symposium, includes studies of the tyrannosaurids Chingkankousaurus fragilis and “Sir William” and the generic status of Nanotyrannus; theropod teeth, pedal proportions, brain size, and craniocervical function; soft tissue reconstruction, including that of “Jane”; paleopathology and tyrannosaurid claws; dating the “Jane” site; and tyrannosaur feeding and hunting strategies. Tyrannosaurid Paleobiology highlights the far ranging and vital state of current tyrannosaurid dinosaur research and discovery. “Despite being discovered over 100 years ago, Tyrannosaurus rex and its kin still inspire researchers to ask fundamental questions about what the best known dinosaur was like as a living, breathing animal. Tyrannosaurid Paleobiology present a series of wide-ranging and innovative studies that cover diverse topics such as how tyrannosaurs attacked and dismembered prey, the shapes and sizes of feet and brains, and what sorts of injuries individuals sustained and lived with. There are also examinations of the diversity of tyrannosaurs, determinations of exactly when different kinds lived and died, and what goes into making a museum exhibit featuring tyrannosaurs. This volume clearly shows that there is much more to the study of dinosaurs than just digging up and cataloguing old bones.” —Donald M. Henderson, Royal Tyrrell Museum of Palaeontology

Author:
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 502

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Author: Joshua B. Smith
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Kenneth Carpenter
Publisher: Cambridge University Press
ISBN: 9780521438100
Category : Nature
Languages : en
Pages : 360

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In recent years dinosaurs have captured the attention of the public at an unprecedented scale. At the heart of this resurgence in popular interest is an increased level of research activity, much of which is innovative in the field of palaeontology. For instance, whereas earlier palaeontological studies emphasized basic morphologic description and taxonomic classification, modern studies attempt to examine the role and nature of dinosaurs as living animals. More than ever before, we understand how these extinct species functioned, behaved, interacted with each other and the environment, and evolved. Nevertheless, these studies rely on certain basic building blocks of knowledge, including facts about dinosaur anatomy and taxonomic relationships. One of the purposes of this volume is to unravel some of the problems surrounding dinosaur systematics and to increase our understanding of dinosaurs as a biological species. Dinosaur Systematics presents a current overview of dinosaur systematics using various examples to explore what is a species in a dinosaur, what separates genders in dinosaurs, what morphological changes occur with maturation of a species, and what morphological variations occur within a species.

Author: Mark Andrew Loewen
Publisher:
ISBN:
Category : Allosaurus
Languages : en
Pages : 652

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Author: Doreen S. Genin
Publisher:
ISBN:
Category : Coelophysis bauri
Languages : en
Pages : 214

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Author: Ashraf M.T. Elewa
Publisher: Springer Science & Business Media
ISBN: 3642162711
Category : Science
Languages : en
Pages : 233

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Computational paleontology is simply a term applied to using computers and its facilities in the field of paleontology. However, we should be exactly precise in describing the term through explaining the main themes of this motivating and attractive scientific field. The uppermost aim of this book is to explain how computation could be competent in fetching fossils to life and the past to present. Computers for paleontologists save time and costs, interpret mysterious events precisely and accurately, visualize the ancient life definitely and undeniably.