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dc.contributor.advisorBagnara, Joseph T.en_US
dc.contributor.authorSherbrooke, Wade Cutting.
dc.creatorSherbrooke, Wade Cutting.en_US
dc.date.accessioned2011-10-31T17:05:16Z
dc.date.available2011-10-31T17:05:16Z
dc.date.issued1988en_US
dc.identifier.urihttp://hdl.handle.net/10150/184327
dc.description.abstractThe integument is the body organ interfacing between the internal and external environments of a lizard. This study explores aspects of its structure, texture, and coloration, relating them to survival strategies of horned lizards. The dermal chromatophore structure of Phrynosoma modestum is described. Color change depends on two cell types, melanophores and iridophores. This cellular arrangement may be typical of lizards utilizing color change for thermoregulation. Color pigment cells (xanthophores and erythrophores) function in pattern formation and background color matching. Experiments on the regulation of color change revealed that (1) -MSH is the prime skin darkening agent, (2) - and -adrenergic receptors also play a role in color change, and (3) temperature is a factor in in vitro and in vivo darkening and lightening responses. Apparently the primary role of color change is thermoregulation. Intraepidermal mechanoreceptors on dorsal body, limb, and head scales were studied, their ultrastructure is described, and their role in defense and survival is explored. The use of the integument for "rain-harvesting" of drinking water by P. cornutum is described, including stereotyped behavior, stereoscopic SEM examination of interscalar channels, experiments on capillary water flow, and an evaluation of micro-ornamentation. Comparisons are made with the putative use of the integument for the collection of rain, fog, or dew for drinking by Moloch and Phrynocephalus. A stereotypic behavior that utilizes positioning of occipital horns and dorsal scale armament is described and hypothesized to be an ophidian antipredator defense. Attacks by Onychomys torridus on P. cornutum and P. modestum were studied to further evaluate the role of occipital horns, dorsal scalation, and dermal collagen as antipredator defenses. Attack behaviors of the grasshopper mice and defense behaviors of the lizards are detailed. The use of color pattern, integumental structures, and mimetic behavior by P. modestum in avoidance of predator detection, through "stone-mimicry," is hypothesized and supported. Aspects of social communication in four species were studied. The importance of olfaction for intraspecific communication and lack of visual color signals is related to the need for chromatic crypticity in order to avoid detection by predators.
dc.language.isoenen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectHorned toads.en_US
dc.subjectIguanas.en_US
dc.subjectSkin.en_US
dc.subjectLizards.en_US
dc.titleIntegumental biology of horned lizards (Phrynosoma).en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.identifier.oclc701102623en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.contributor.committeememberHadley, Mac E.en_US
dc.contributor.committeememberKodric-Brown, Astriden_US
dc.contributor.committeememberSmith, Robert L.en_US
dc.contributor.committeememberWerner, Floyd G.en_US
dc.identifier.proquest8809946en_US
thesis.degree.disciplineEcology & Evolutionary Biologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.namePh.D.en_US
refterms.dateFOA2018-05-25T18:57:26Z
html.description.abstractThe integument is the body organ interfacing between the internal and external environments of a lizard. This study explores aspects of its structure, texture, and coloration, relating them to survival strategies of horned lizards. The dermal chromatophore structure of Phrynosoma modestum is described. Color change depends on two cell types, melanophores and iridophores. This cellular arrangement may be typical of lizards utilizing color change for thermoregulation. Color pigment cells (xanthophores and erythrophores) function in pattern formation and background color matching. Experiments on the regulation of color change revealed that (1) -MSH is the prime skin darkening agent, (2) - and -adrenergic receptors also play a role in color change, and (3) temperature is a factor in in vitro and in vivo darkening and lightening responses. Apparently the primary role of color change is thermoregulation. Intraepidermal mechanoreceptors on dorsal body, limb, and head scales were studied, their ultrastructure is described, and their role in defense and survival is explored. The use of the integument for "rain-harvesting" of drinking water by P. cornutum is described, including stereotyped behavior, stereoscopic SEM examination of interscalar channels, experiments on capillary water flow, and an evaluation of micro-ornamentation. Comparisons are made with the putative use of the integument for the collection of rain, fog, or dew for drinking by Moloch and Phrynocephalus. A stereotypic behavior that utilizes positioning of occipital horns and dorsal scale armament is described and hypothesized to be an ophidian antipredator defense. Attacks by Onychomys torridus on P. cornutum and P. modestum were studied to further evaluate the role of occipital horns, dorsal scalation, and dermal collagen as antipredator defenses. Attack behaviors of the grasshopper mice and defense behaviors of the lizards are detailed. The use of color pattern, integumental structures, and mimetic behavior by P. modestum in avoidance of predator detection, through "stone-mimicry," is hypothesized and supported. Aspects of social communication in four species were studied. The importance of olfaction for intraspecific communication and lack of visual color signals is related to the need for chromatic crypticity in order to avoid detection by predators.


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