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Sharks are an objectively diverse group of animals; ranging in maximum size from 2,000cm (whale shark) to 17cm (dwarf lantern shark); occupying habitats that are periodically terrestrial (epaulette shark) to the deepest parts of the ocean (frilled shark); relying on a diversity of diets from plankton to marine mammals; with vast amounts of morphology diversity such as the laterally expanded heads of hammerhead species, the elongate caudal fins of thresher species, and the tooth embedded rostrum of saw shark species representing some of the anatomical extremes. Yet despite these obvious differences in morphology, physiology, and ecology, the challenges associated with studying hard to access, large bodied, pelagic animals have limited our comparative understanding of form and function as it relates to swimming within this group. The majority of shark swimming studies examine species that succeed in captivity, which are usually benthic associated sharks that spend time resting on the substrate. These studies have also been limited by the use of flumes, in which the unidirectional flow and small working area precludes the analysis of larger animals, volitional swimming, and maneuvering. The few existing volitional kinematics studies on sharks quantify two-dimensional kinematics which are unable to capture movements not observable in the plane of reference. With this study, we quantified the volitional swimming kinematics of sharks in relation to morphological, physiological, and ecological variation among species. We developed a technique to analyze three-dimensional (3D) kinematics in a semi-natural, large volume environment, which, to our knowledge, provides the first3D analysis of volitional maneuvering in sharks. We demonstrated that Pacific spiny dogfish and bonnethead sharks rotate the pectoral fins substantially during yaw (horizontal) maneuvering and is correlated with turning performance. We proposed that ecomorphological differences correlate with the varied maneuvering strategies we observed between the two species. We also found that there is some mechanical constraint on shark pectoral fin shape that is explained by phylogenetic relationships but describe a continuum of morphological variables within that range. We propose standardized terminology and methodology for the future assessment of shark pectoral fin morphology and function. As with previous studies, the ease of access to species was a challenge in this study and future studies should continue to assess the functional ecomorphology of shark pectoral fins among species. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

Proefschrift--Leyden. / Curriculum vitae. "Dit proefschrift verschijnt met obereenkomstige paginering in de Archives néerlandaises de zoologie, tome XII, 1e livraison." eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 109-111.

Thesis (Ph. D.)--University of Chicago, Department of Geophysical Sciences, August 2003. / Includes bibliographical references. Also available on the Internet.

Thesis--M. Phil., University of Hong Kong, 1981.

published_or_final_version / Zoology / Master / Master of Philosophy

Thesis (D. Sc.)--London. / Includes bibliographical references.

Five populations of the threespine stickleback, Gasterosteous aculeatus,from the upper Cowichan River system (Vancouver Island, British Columbia) were surveyed to assess interpopulation levels of variability in trophic morphology. Phenotypic divergence is assumed to be a post-glacial event. Nine characters were scored; eight were related to feeding and the ninth character was lateral plate number. All populations surveyed were the low plate morph; however populations of Gasterosteus in lakes lacking piscivorous fish had significantly fewer lateral plates than populations in lakes with predatory fish species. Three trophic 'morphotypes' were identified, each associated with one of three lake environments. Populations inhabiting benthic dominated environments ('benthic morph') were found to possess reduced gill raker number and reduced gill raker length but increased upper jaw length relative to populations from lentic environments ('limnetic morph'). An intermediate morph may also exist and is characterized by a morphology suitable to either trophic regime. Analysis of stomach contents showed diet type (benthic or limnetic) to be significantly dependent on morph. The functional significance of differences in trophic morphology was investigated in three feeding experiments using a representative population from each morphotype. The longer jaw of the benthic and intermediate morphs allowed them to ingest a larger benthic prey than the limnetic. No behavioural component to benthic foraging success between populations was identified, although increased jaw length shortened the time spent manipulating prey. Both the intermediate and limnetic morphs were better foragers on an experimental limnetic prey than was the benthic. Head length, snout length, gill raker density and gill raker number were strongly correlated with limnetic foraging success. The quantitative genetics governing the eight trophic characters were investigated using the same three representative populations. Broad sense estimates of character heritabilities ranged from 0.132 to 0.677; all estimates were significant. Character genetic correlations were reasonably strong (0.3 ≤ |rG| ≤ 0.9), while character correlations arising through environment tended to be lower. Cluster analyses of the genetic correlation matrices defined two character suites, the first grouped measures of head shape, the second grouped measures of gill raker structure. The patterns of genetic correlations suggest the three populations are distinct races. Selection gradients for divergence between morphotype indicated that directional selection had operated hardest on head length, snout length, gill raker number, head depth and upper jaw length; hence selection has operated to modify characters related to food size. The benthic-limnetic and intermediate-limnetic morphs were separated by the greatest selection distance while the intermediate-benthic morphs were separated by the shortest selection distance. These results support the conclusion that directional selection, arising from trophic resource differences between lakes, has organized interpopulation variability for Gasterosteus within the upper Cowichan drainage. The racial distinction of each population coupled with the functional significance of some components of trophic morphology indicate that at least the benthic and limnetic morphs must be considered 'ecotypes'. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (Ph. D.)--University of Chicago, Department of Geophysical Sciences, December 2003. / CD-ROM contains figures 2.1-4.8 and A.1 in PDF format. Includes bibliographical references. Also available on the Internet.

Thesis (Ph.D.)--University of Texas at Arlington, 2009.