scholarly journals Jaw Mechanics in Basal Ceratopsia (Ornithischia, Dinosauria)

2009 ◽  
Vol 292 (9) ◽  
pp. 1352-1369 ◽  
Author(s):  
Kyo Tanoue ◽  
Barbara S. Grandstaff ◽  
Hai-Lu You ◽  
Peter Dodson
Keyword(s):  
Jaw Mechanics

Jaw mechanics in dolichofacial and brachyfacial phenotypes: A longitudinal cephalometric-based study

2017 ◽  
Vol 20 ◽  
pp. 145-150 ◽  
Author(s):  
L. R. Iwasaki ◽  
Y. Liu ◽  
H. Liu ◽  
J. C. Nickel
Keyword(s):  
Jaw Mechanics

Evolutionary Patterns in the History of Permo-Triassic and Cenozoic Synapsid Predators

2002 ◽  
Vol 8 ◽  
pp. 267-288 ◽  
Author(s):  
Blaire Van Valkenburgh ◽  
Ian Jenkins
Keyword(s):  
Fossil Record ◽  
Late Carboniferous ◽  
Second Phase ◽  
Evolutionary Patterns ◽  
Large Size ◽  
Jaw Mechanics ◽  
History Of ◽  
Trends Over Time ◽  
Energetic Constraints ◽  
Over Time

Synapsids include modern mammals and their fossil ancestors, the non-mammalian synapsids, or ‘mammal-like reptiles' of old classifications. The synapsid fossil record extends from the Late Carboniferous to the present, a span of nearly 300 million years. However, it can be broken into two distinct phases of diversification, separated by about 150 million years. The first phase extends from the Late Carboniferous to the mid-Triassic, includes the first large land predators on Earth, and is almost entirely non-mammalian. The second phase begins about 65 million years ago after the demise of the dinosaurs, includes only mammals, and extends to the present. In this overview of synapsid predators, we emphasize terrestrial species of large size, and their adaptations for killing and feeding, rather than locomotion. Despite fundamental differences in jaw mechanics and tooth morphology, there are significant parallels in the non-mammalian and mammalian radiations of synapsid predators. Both groups evolve sabertooth forms more than once, and both evolve short-snouted, powerful biting forms. In addition, both the Late Carboniferous—Triassic and Cenozoic phases are characterized by repeated patterns of clade replacement, in which one or a few clades evolve large size and seem to dominate the carnivore guild for several million years, but then decline and are replaced by new taxa. Moreover, within both ancient and Cenozoic predator clades, there are parallel trends over time toward increased body size and hypercarnivory that likely result from a combination of interspecific competition and energetic constraints.

scholarly journals Killing them softly: Ontogeny of jaw mechanics and stiffness in mollusk‐feeding freshwater stingrays

2019 ◽  
Vol 280 (6) ◽  
pp. 796-808 ◽  
Author(s):  
Kelsi M. Rutledge ◽  
Adam P. Summers ◽  
Matthew A. Kolmann
Keyword(s):  
Jaw Mechanics

A new pachypleurosaur (Reptilia: Sauropterygia) from the Middle Triassic of Monte San Giorgio, Switzerland

1989 ◽  
Vol 323 (1212) ◽  
pp. 1-73 ◽  
Keyword(s):  
New Genus ◽  
Middle Triassic ◽  
Cladistic Analysis ◽  
Morphological Description ◽  
New Genus And Species ◽  
Lower Jaw ◽  
Jaw Mechanics ◽  
The Status ◽  
Mode Of Life ◽  
Aquatic Mode

Pachypleurosaur material from the Middle Triassic ‘ Grenzbitumen’-horizon (Anis-Ladin boundary) of Monte San Giorgio, Kanton Tessin, Switzerland, is described as a new genus and species, Serpianosaurus mirigiolensis .A detailed morphological description is followed by a quantitative analysis. The taxon differs from other pachypleurosaurids primarily by its relatively large skull and its straight lower jaw. Rib pachyostosis is absent. In most characters the taxon remains plesiomorphous with respect to other pachypleurosaurs from the Middle Triassic deposits of Monte San Giorgio, which accords well with its early stratigraphic occurrence at that locality. Sexual dimorphism is expressed by the size and shape of the humerus. A cladistic analysis shows the Pachypleurosauridae to constitute the sistergroup of all other Sauropterygia. The Sauropterygia and the Placodontia together form a monophyletic group, the Euryapsida, which is subordinated to the Diapsida and to the Neodiapsida, but which is classifed outside the archosauromorph-lepidosauromorph dichotomy within the Neodiapsida. A concluding paragraph discusses the status of the pachypleurosaurs within the Sauropterygia. Skull structure, and jaw mechanics in particular, suggest a relatively plesiomorph position of pachypleurosaurs within the Sauropterygia. Their adaptation to an aquatic mode of life was not carried to the degree observed in other sauropterygians, and the ability for rapid and deep dives seems to have been limited by middle-ear structure.

Botulinum Toxin Injection for the Treatment of Oromandibular Dystonia

1989 ◽  
Vol 98 (2) ◽  
pp. 93-97 ◽  
Author(s):  
Andrew Blitzer ◽  
Paul E. Greene ◽  
Mitchell F. Brin ◽  
Stanley Fahn
Keyword(s):  
Botulinum Toxin ◽  
Botulinum Toxin Injection ◽  
The Body ◽  
Oromandibular Dystonia ◽  
Jaw Muscles ◽  
Neurologic Disorder ◽  
Motor Processing ◽  
Temporomandibular Joint Syndrome ◽  
Jaw Mechanics ◽  
Generalized Dystonia

Dystonia is a neurologic disorder characterized by abnormal, involuntary movements causing twisting and turning postures; it is postulated to be a disorder of central motor processing. The dystonias, when classified by region of the body involved, have been characterized as focal, segmental, and generalized. Focal dystonia can affect jaw mechanics, leading to forceful contraction of the jaw muscles and resulting in inappropriate deviation of the jaw. Localized injections of botulinum toxin have been used successfully in the management of other focal or segmental dystonias. We have treated 20 oromandibular dystonia patients with botulinum toxin. Six patients had only jaw and tongue involvement; 11 had blepharospasm and jaw involvement; and three had jaw involvement as part of a more generalized dystonia. Five patients had been diagnosed originally and treated as having temporomandibular joint syndrome. All but one of the patients had improvement of their symptoms with the toxin injections. The patients averaged 47% improvement with the injections.

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