The family Iguanidae is almost completely restricted to the Western Hemisphere with its main radiations occurring in North and South America. There are also representatives on Fiji, Tonga and the Galapagos Islands, in the Pacific Ocean. Distantly related forms are also found on Madagascar off the Southeastern Coast of Africa. Although the iguanid lizards are familiar to most scientists interested in the tropics, their anatomy and evolution is poorly understood.

The 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.

No description available.

Male growth is best described by a von Bertalanffy growth model and female growth by a logistic growth model. This sexual dimorphism is correlated with greater relative surface activity and lower survivorship of juvenile males when compared to juvenile females. Early-hatching (first clutch) offspring exhibit greater body size and survivorship compared to late-hatching (second clutch) offspring. (Abstract shortened with permission of author.)

No description available.

The anterior myology of Crotaphytus wislizeni and C. collaris is described in detail and a statistical analysis is made of the differences in the relative bone sizes, and the number of eggs per clutch, as well as other taxonomic characters previously applied to these species. The significant differences found with respect to the shape of the skull, that of the body, and the character of the hyoid are correlated with muscular development and habits of the two species. The descriptive material is accompanied by detailed myological and osteological illustrations of C. wislizeni. Comparative notes are made on C. reticulatus which is found to be intermediate between these species with respect to its myology. The results of this study indicate that Gambelia and Crotaphytus are synonymous.

Evolution of sex chromosomes and karyotypes in iguanas (Squamata: Pleurodonta) PhD Thesis Marie Altmanová Abstract This PhD thesis is composed of five published articles and one manuscript, and is focused on the evolution of the sex chromosomes and karyotype of the iguanas (Pleurodonta). Based on our primary research of available data, only male heterogamety (XX/XY) with ancestral karyotype 2n = 36 chromosomes was recorded in iguanas. However, in many species sex chromosomes have not been uncovered by classical cytogenetics, probably due to their homomorphy. The partially-known X chromosome content of Anolis carolinensis allowed us to compare the relative gene doses of X-specific genes between male and female of representatives of all iguana families, and to reveal homologous and well-differentiated sex chromosomes across all iguanas, with the exception of basilisks. Thus, due to the comparable age with sex chromosomes of mammals and birds, the results put into question the importance of endothermy for the formation of stable sex chromosomes. The striking feature of the iguanas is the relatively frequent occurrence of multiple sex chromosomes in their karyotypes. Using the ancestral state analysis of the type of sex chromosomes, it has been found that these multiple sex chromosomes developed at least twelve...

We are now in the midst of a mass extinction crisis. The top threats to biodiversity include habitat destruction, pollution, over-harvesting, and invasive species. The field of conservation genetics seeks to understand these threats and devise management to preserve taxa with the ability to cope with environmental change. Preserving genetic variation and the processes in which variation is created and maintained is vital to long-term conservation goals. Limited conservation resources are cause for the prioritization of taxa and areas. Nine basic methods of prioritization have been developed. Though there are differences in these methods, and thus in the resulting target areas, many, including biodiversity hotspots, list Mesoamerica, in which the highest diversity of iguanids confined to a single genus, Ctenosaura, occur. Though ctenosaurs are the most diverse genus of iguanas, have the most Redlisted species, lack protection and are in danger of extinction, they have been overlooked. The Ctenosaura palearis complex, occurs in central Mesoamerica and is made up of four endangered species. In order aid in the conservation of this biodiversity, a multi-scale molecular evaluation of this complex was preformed. I first used a species tree approach to elucidate the relationships between the focal species, showing that these species have gone through recent and rapid speciation, resulting in four closely related endemics. Thus, the nominal groupings should be upheld and given individual protection. Second, I evaluated the degree to which gene flow from the widely distributed congener threatens the genetic distinctiveness of the endemic C. bakeri. Low levels of introgression indicated no current threat. Hybridization could increase if habitat destruction or changes in relative abundance increase the probability of interbreeding. Continued monitoring of this situation is justified. Third, I used a variety of population genetic techniques to elucidate the genetic structure within and among populations of C. melanosterna. These results indicate that the populations in the Valle de Aguán and Cayos Cochinos are not interchangeable thus protection of both areas is necessary, and extreme caution should be used when implementing breeding and translocation programs. Local conservation efforts may be evaluated and developed using this information.

Se evaluaron los efectos cicatrizante, antiinflamatorio y antimicrobiano de la grasa de Iguana Verde (Iguana iguana) de hembras grávidas procedentes del distrito de Castilla, provincia de Piura, departamento de Piura (Perú). La grasa demostró que a dosis de 0,55 mL/kg (vía tópica) tiene actividad cicatrizante y claras evidencias de atenuar y/o borrar cicatrices sobre lesiones inducidas en ratas; también mostró tener propiedad antiiflamatoria mediante edema inducido por xyleno en oreja de ratón. Los resultados microbiológicos demostraron actividad antimicrobiana poco significativa. El estudio químico analítico reveló: proteínas totales (12%), albúmina (6,4%), úrea (0,05%),Fe (1ppm), Al (2ppm) y Cr (2ppm). Un análisis de composición de ácidos grasos realizado por Cromatografía gas-líquida en columna mostró los siguientes ácidos: mirístico (0,9 %), palmítico (28,9%), palmitoleico (6,2%), hexadecatrienoico ω4 (0,2%), esteárico (7,0%), oleico ω7 (4,0%), oleico ω9 (34,9%), linoleico ω6 (5,2%), linolénico ω3 (9,7%), araquídico (0,1%), gadoleico ω9 (0,5%), eicosadienoico ω6 (0,1%), eicosatrienoico ω3 (0,3%), araquidónico ω3 (0,1%), araquidónico ω6 (0,1%), docosapentaenoico ω3 (0,1%). Asimismo, se investigaron las vitaminas E por HPLC y vitamina A por la técnica de la USP XXVIII concluyéndose que la grasa de iguana no contiene estas vitaminas. Respecto a su DL50 es inócua, la prueba de sensibilidad cutánea y reactividad aguda en conejos indica que no es irritante a la piel por lo que estaríamos ante una fuente de materia prima natural con un gran potencial para su empleo en dermatología. / The cicatrizant effects were evaluated, anti-inflammatory and antimicrobial of the fat of Green Iguana (Iguana iguana) of pregnant female coming from the district of Castilla, county of Piura, department of Piura (Peru). The fat demonstrated that to dose of 0,55 mL / kg (via topical) has healing activity and whites evidences of to attenuate and/or to erase scars on lesions induced in rats; also showed to have property anti-inflammatory mediating edema induced by xyleno in mouse ear. The microbiological results demonstrated little significant microbial activity. The chemical analytic study revealed: total (12%) proteins, albumin (6,4%), úrea (0,05%), Fe (1ppm), Al (2ppm) and Cr (2ppm). An analysis of composition of fatty acid carried out by gas-liquid Chromatography in column showed the following acids: myristic (0,9%), palmitic (28,9%), palmitoleic (6,2%), hexadecatrienoic ω4 (0,2%), stearic (7,0%), oleic ω7 (4,0%), oleic ω9 (34,9%), linoleic ω6 (5,2%), linolenic ω3 (9,7%), arachidonic (0,1%), gadoleic ω9 (0,5%), eicosadienoic ω6 (0,1%), eicosatrienoic ω3 (0,3%), araquidonic ω3 (0,1%), araquidonic ω6 (0,1%), docosapentaenoic ω3 (0,1%). Also, the vitamins E were investigated by HPLC and vitamin A by the technique of USP XXVIII being concluded that the iguana fat doesn't contain these vitamins. Regarding their DL50 it is innocuous, the test of cutaneous sensibility and sharp reactivity in rabbits it indicates that it is not irritating to the skin for what we would be before a matter source prevails natural with a great potential for their employment in dermatology.

Thesis (M.S.)--Indiana University, 2009. / Title from screen (viewed on August 27, 2009). Department of Geography, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Jan Ramer, Aniruddha Banergee, Jeffery Wilson. Includes vita. Includes bibliographical references (leaves 47-52).