Comparative biomechanics of cranial kinesis in reptiles
Abstract
[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] "The vertebrate skull is a composite organ made from structures that arise from different developmental, evolutionary and biomechanical phenomena. Of these parts, the chondrocranium is among the key skeletal elements as it serves not only as primordial protection for the brain and sensory structures, but as the cartilaginous and ultimately bony structure the jawed feeding apparatus is formed about. Despite the great diversity of the head structure and function among gnathostomes, they all share the common problem of articulating the first arch cartilages, particularly the suspensorium to the neurocranium. Although this articulation is mediated indirectly via the hyomandibula in fishes, as this suspensorial element transitioned to form the ear ossicle (i.e., the columella) in early tetrapods, the palatoquadrate cartilage formed a new direct link with the neurocranium via the otic joint (Brazeau and Ahlberg, 2006; Gardner et al., 2010) and palatobasal joint (e.g., Iordansky, 1989). Despite considerable variation in the construction of these joints, they all share the function of linking the jaws to the neurocranium. ... Cranial kinesis is a manifestation of many different morphological, histological, mechanical, and behavioral variables. Therefore, making informed predictions about structure-function relationships is challenging. Regardless, new methods are enabling us to better capture joint shape, function and performance. Thus, here we explore the diversity of form, function and performance across a small, yet diverse sample sauropsids of varying kinetic behaviors. Using novel imaging and modeling techniques we quantify aspects of cranial morphology which affect kinetic behaviors and elucidate promising future avenues of research. These findings will provide new insights into how developmentally disparate portions of the skull function together in tetrapods, the evolution and biomechanics of ball and socket joints, and the evolution of secondary cartilages."--Introduction
Degree
M.S.
Thesis Department
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