This study examined the ant communities of several grasslands of the Australian Capital Territory (ACT) and their relevance to the pink-tailed legless lizard, Aprasia parapulchella (Pygopodidae). A. parapulchella is a fossorial species that shares burrows with, and eats the brood of, several grassland ant species. Foraging ants were collected from sites by pitfall trapping throughout one calendar year and comparisons of ant communities made between seasons and sites of differing vegetation structure. Competition between ant species for artificial nest sites and the effects of temperature on selection of nest site selection were also studied. The role that ants play in the distribution of A. parapulchella was investigated by (i) comparing ant faunas from several sites throughout the geographic range of the lizard, including sites in New South Wales and Victoria, (ii) performing feeding preference experiments with A. parapulchella, and (iii) investigating the seasonal nature of brood production and nest establishment by ants in ACT grasslands. Major findings were used to make recommendations to assist in the management, including rehabilitation, of A. parapulchella grassland sites. Low insolation appears to significantly affect the ant species composition of grassland sites in the ACT relative to other Australian vegetation types. In the ACT grassland sites, large species of the Dominant Dolichoderinae functional group were absent, or present only in very low numbers. The communities were species-poor relative to other Australian studies with only 60 species being recorded across all sites studied, with no more than 21 species recorded at any site on any sampling occasion. Whilst ant species community structure was highly variable between seasons and sites, more than 95% of ants were from the three functional groups, Dominant Dolichoderinae, Generalized Myrmicinae and Opportunists. The communities were numerically dominated throughout the year by the ubiquitous species groups Iridomyrmex 'rufoniger' and Rhytidoponera 'metallica'. Almost all taxa increased in foraging abundance during summer months and Pheidole spp., Monomorium spp., Crematogaster sp. Paratrechina sp. and Notoncus ectalomoides were occasionally locally abundant. There were no significant relationships between ant and vegetation community structures, but Solenopsis sp. showed an alliance with sites that had a high abundance of Themeda australis (kangaroo grass), whilst Crematogaster sp. and Paratrechina sp. are potential bioindicators of disturbance from grazing or pasture improvement. Iridomyrmex 'rufoniger' were the numerically dominant foraging ants, making up 50% of all captures, but they held only 80% of their nest sites when faced with competition from other species. R. 'metallica' and Pheidole spp. on the other hand, gained 80% more nests than they lost to other taxa. I. 'rufoniger' and R. 'metallica' both preferred nest sites with warmer temperature regimes when given the choice, and this assisted them to tend brood throughout the year. All ant species in ACT grasslands had summer peaks in brood production. Most nests were inactive throughout the cooler months and nest founding was predominantly between September and November. The common species, Iridomyrmex spp., Paratrechina sp. and R. 'metallica' held winged reproductives in their nests from April and all ant taxa had released all alates by mid- November. Although there were differences in ant community structure throughout the range of A. parapulchella, the ubiquitous R. 'metallica' and I. 'rufoniger' were always abundant, whilst again, Dominant Dolichoderinae and associated subordinate taxa were absent or present only in relatively low numbers. The lizards consumed brood from all the common ant species in ACT grasslands and showed preference for consuming brood of, and living with, small Iridomyrmex spp. The range of the small Iridomyrmex spp. preferred by A. parapulchella extends far beyond that of the lizard. Its distribution is apparently not restricted by the range of its ant prey species. For rehabilitation of A. parapulchella sites in the ACT, it is recommended that a significant ground cover of native grasses is established to ensure the low abundance of large and territorial ants from the Dominant Dolichoderinae functional group. Along with a high abundance of shallow surface rocks, this will ensure the establishment of ant communities that are numerically dominated by small Iridomyrmex spp., which are preferred by A. parapulchella for homesite sharing and as a food source.

Reptiles exhibit marked diversity in sex-determining mechanisms. Many species exhibit genotypic sex determination (GSD) with male heterogamety (XX females/XY males), others have GSD with female heterogamety (ZW females/ZZ males), and still others exhibit temperature-dependent sex determination (TSD). The distribution of these mechanisms throughout the reptile phylogeny implies evolutionary lability in sex determination, and in some lineages there has been a number of transitions between GSD and TSD. Despite this diversity, GSD and TSD have traditionally been viewed as mutually-exclusive mechanisms of sex determination in reptiles, since there is little evidence for their co-occurrence. Considerable empirical and theoretical effort has been directed towards understanding the adaptive significance of TSD in reptiles. In comparison, there has been little focus on understanding how evolutionary transitions between GSD and TSD occur at a genetic and mechanistic level. I addressed this question by applying both empirical and theoretical approaches to investigate interaction of genotypic and temperature influences in the sex determination of two endemic species of Australian lizards. The three-lined skink, Bassiana duperreyi, has XX/XY chromosomal sex determination, yet a previous investigation reported a significant male bias in the sex ratio of eggs incubated at low temperatures. To enable an explicit test for temperature induced sex reversal in this species, a 185 bp Y chromosome marker was isolated by Amplified Fragment Length Polymorphism (AFLP) analysis. The marker was subsequently converted into a duplex PCR assay that co-amplified a 185 bp (or 92 bp) Y chromosome fragment and a 356 bp fragment of the single-copy nuclear gene C-mos (from both sexes) as a positive control. The accuracy of the PCR sex assay was tested on 78 individuals for which sex reversal was not expected. PCR genotype and sex phenotype were concordant for 96% of the animals. This is one of the very few sex tests developed for a reptile, and the first report of Y chromosome sequence from a reptile. The PCR assay was subsequently applied to genotype hatchlings from both cool (16-7.5C) and warm (22-7.5C) cyclical incubation temperature treatments, and identified sex reversal in 15% of genotypically female (XX) embryos (n=26) from the cool treatment, but no sex reversal in eggs from the warmer treatment (n=35). Thus, low incubation temperatures can over-ride genotypic sex determination in B. duperreyi, indicating that GSD and TSD co-occur in this species. The Central bearded dragon, Pogona vitticeps (Agamidae), has ZZ/ZW chromosomal sex determination, and is a member of a lizard family in which GSD and TSD are both widespread, indicating evolutionary lability in sex determination. AFLP analysis was applied to isolate homologous Z and W chromosome-linked markers (71 bp and 72 bp, respectively) from this species. The AFLP sequences were subsequently extended into larger genomic fragments by a reiterated genome walking procedure, producing three non-overlapping contigs of 1.7 kb, 2.2 kb and 4.5 kb. The latter two fragments were verified as distinct, homologous Z/W chromosome fragments by PCR analyses. An amplified 3 kb fragment of the 4.5 kb contig was physically mapped to metaphase spreads, identifying the W microchromosome, and for the first time in this species, the Z microchromosome. PCR analyses indicated the presence of homologous sequences in other Australian agamid species, including both GSD and TSD species. The isolated sequences should therefore prove useful as a comparative genomic tool for investigating the genomic changes that have occurred in evolutionary transitions between sexdetermining mechanisms in agamids, by enabling the identification of chromosomes in TSD species that are homologous to the sex chromosomes of P. vitticeps. The isolated sequences were further converted into a duplex DNA sex assay that co-amplified a 224 bp W chromosome fragment and a 963 bp positive control fragment in both sexes. This PCR assay diagnosed chromosomal sex in three Pogona species, but was not effective outside the genus. Incubation treatment of P. vitticeps eggs revealed a strong and increasing female bias at high constant temperatures (34-36C), but an unbiased sex ratio between 22-32C. Hatchlings from three clutches split between 28C and 34 or 36C incubation treatments were genotyped with the W chromosome AFLP marker. At 28C, the sex ratio was 1:1 but the high temperature treatments produced 2 males and 33 females. All but one of the 30 lizards (97%) incubated at 28C had concordant sex phenotype and genotype, but only 18 of 35 animals (51%) from the high temperature treatment were concordant. All discordant animals were genotypic males (ZZ) that developed as females. Thus, temperature and genotypic influences can interact to determine sex in P. vitticeps. These empirical findings for B. duperreyi and P. vitticeps were extended into a novel theory for the evolution of sex-determining mechanisms in reptiles, working within the framework that species with temperature-induced reversal of chromosomal sex determination are a window to transitional stages of evolution between GSD and TSD. A model was derived from the observation that in both lizards, an extreme of incubation temperature causes sex reversal of the homogametic genotype. In this model, the strength of a genetic regulatory signal for sex determination must exceed a threshold for development of the homogametic sex to occur (male in Pogona, female in Bassiana). The strength of this signal is also temperature-sensitive, so diminishes at extremes of temperature. Simulation modelling demonstrated that increasing the relative magnitude of the threshold for sexual development can cause evolutionary transitions between GSD and TSD. Even more remarkably, decreasing the relative magnitude of the threshold value causes an evolutionary transition between female and male heterogametic GSD. Quantitative adjustment of a single model parameter (the threshold value) thus charts a continuous evolutionary pathway between the three principal mechanisms of sex determination in reptiles (XX/XY-ZZ/ZW-TSD), which were previously considered to be qualitatively distinct mechanisms. The experimental demonstration of temperature-induced reversal of chromosomal sex determination in both B. duperreyi and P. vitticeps presents a challenge to the traditional view that reptilian sex determination is strictly dichotomous (GSD or TSD), and suggests instead that sex determination in reptiles consists of a continuum of systems of interaction between genotypic and temperature influences. Simulation modelling provided solid theoretical support for this proposition, demonstrating that transitions along this continuum are effected simply through shifts in the mean population value for the sex-determining threshold, without requiring substantial genotypic innovation. An important implication of this theory is that transitions between XX/XY and ZZ/ZW modes of GSD may retain the same sex chromosome pair, and the same primary sexdetermining gene, in contrast to previous models for heterogametic transitions. A more immediate implication of these findings is that many reptile species believed to have strict TSD (in particular, lizards and crocodilians), may in fact have a sex-determining system of GSD-TSD interaction, where there is an equilibrium between GSD and TSD individuals within the population.

The St. Croix ground lizard, Ameiva polops, is a United States endangered species endemic to St. Croix, U.S. Virgin Islands. It was extirpated from St. Croix Proper by invasive mongooses, and remaining populations are on small, nearby cays. In the summer of 2008, as part of the recovery plan for this species, I worked in a multi-agency effort to translocate a population of A. polops to Buck Island Reef National Monument, U.S. Virgin Islands to focus on two main objectives: 1) examine the detection probability of A. polops and infer the consequences of it on population estimates; and 2) examine whether A. polops may deplete its prey base or alter the arthropod assemblage at the translocation site. We used a soft-release strategy for the translocation, in which 57 lizards were initially contained in a series of eight 10 m x 10 m enclosures in the habitat on Buck Island for monitoring. As part of the initial monitoring I conducted visual surveys through all enclosures, with the known number of lizards, to calculate the detection probability and to demonstrate how many individuals would be estimated using visual encounter surveys of this known population. Adjacent to enclosures housing A. polops were control enclosures, without A. polops, which I used to test whether the translocated lizards would impact their prey base over 6 weeks. I found that the detection probability of A. polops is very low (<0.25), which causes population sizes to be severely underestimated, even using some mark-resight techniques. My study of A. polops on the prey community indicated that the lizards generally had no effect on abundance or diversity of arthropods in general, though they may cause small changes for particular taxa. My results help corroborate other evidence that accuracy of population enumeration techniques needs to be improved in order to adequately understand the status of wildlife populations. Additionally, prey resources do not seem to be limiting A. polops in the short-term, and I expect the population will grow, expanding through Buck Island. Future monitoring will be carried out by the National Park Service using robust mark-resight techniques.

The locomotion of organisms whether by running, flying, or swimming is the result of multiple degree-of-freedom nervous and musculoskeletal systems interacting with an environment that often flows and deforms in response to movement. A major challenge in biology is to understand the locomotion of organisms that crawl or burrow within terrestrial substrates like sand, soil, and muddy sediments that display both solid and fluid-like behavior. In such materials, validated theories such as the Navier-Stokes equations for fluids do not exist, and visualization techniques (such as particle image velocimetry in fluids) are nearly nonexistent. In this dissertation we integrated biological experiment, numerical simulation, and a physical robot model to reveal principles of undulatory locomotion in granular media. First, we used high speed x-ray imaging techniques to reveal how a desert dwelling lizard, the sandfish, swims within dry granular media without limb use by propagating a single period sinusoidal traveling wave along its body, resulting in a wave efficiency, the ratio of its average forward speed to wave speed, of approximately 0.5. The wave efficiency was independent of the media preparation (loosely and tightly packed). We compared this observation against two complementary modeling approaches: a numerical model of the sandfish coupled to a discrete particle simulation of the granular medium, and an undulatory robot which was designed to swim within granular media. We used these mechanical models to vary the ratio of undulation amplitude (A) to wavelength (λ) and demonstrated that an optimal condition for sand-swimming exists which results from competition between A and λ. The animal simulation and robot model, predicted that for a single period sinusoidal wave, maximal speed occurs for A/ λ = 0.2, the same kinematics used by the sandfish. Inspired by the tapered head shape of the sandfish lizard, we showed that the lift forces and hence vertical position of the robot as it moves forward within granular media can be varied by designing an appropriate head shape and controlling its angle of attack, in a similar way to flaps or wings moving in fluids. These results support the biological hypotheses which propose that morphological adaptations of desert dwelling organisms aid in their subsurface locomotion. This work also demonstrates that the discovery of biological principles of high performance locomotion within sand can help create the next generation of biophysically inspired robots that could explore potentially hazardous complex flowing environments.

No description available.

<p>Changing environmental conditions may present substantial challenges to organisms experiencing them. In animals, the fastest way to respond to these changes is often by altering behavior. This ability, called behavioral flexibility, varies among species and can be studied on several levels. First, the extent of behavioral flexibility exhibited by a species can be determined by observation of that species' behavior, either in nature or in experimental settings. Second, because the central nervous system is the substrate determining behavior, neuroanatomy can be studied as the proximate cause of behavioral flexibility. Finally, the ultimate causation can be examined by studying ecological factors that favor the evolution of behavioral flexibility. In this dissertation, I investigate behavioral flexibility across all three levels by examining the relationship between habitat structure, the size of different structures within the brain and total brain size, and behavioral flexibility in six closely-related species of Puerto Rican <italic>Anolis</italic> lizards. <italic>Anolis</italic> lizards provide an excellent taxon for this study as certain species, including those used here, are classified as belonging to different ecomorphs and are morphologically and behaviorally specialized to distinct structural habitat types.</p><p>In order to determine the presence of behavioral flexibility in <italic>Anolis</italic>, I first presented <italic>Anolis evermanni</italic> with a series of tasks requiring motor learning and a single instance of reversal learning. <italic>Anolis evermanni</italic> demonstrated high levels of behavioral flexibility in both tasks.</p><p>To address the pattern of brain evolution in the <italic>Anolis</italic> brain, I used a histological approach to measure the volume of the whole brain, telencephalon, dorsal cortex, dorsomedial cortex, medial cortex, dorsal ventricular ridge, cerebellum, and medulla in six closely-related species of Puerto Rican <italic>Anolis</italic> lizards belonging to three ecomorphs. These data were analyzed to determine the relative contribution of concerted and mosaic brain evolution to <italic>Anolis</italic> brain evolution. The cerebellum showed a trend toward mosaic evolution while the remaining brain structures matched the predictions of concerted brain evolution. </p><p>I then examined the relationship between the complexity of structural habitat occupied by each species and brain size in order to determine if complex habitats are associated with relatively large brains. I measured brain volume using histological methods and directly measured habitat complexity in all six species. Using Principal Component Analysis, I condensed the measures of habitat structure to a single variable and corrected it for the scale of each lizard species' movement, calling the resulting measurement relevant habitat complexity. I tested the relationship between relative volume of the telencephalon, dorsal cortex, dorsomedial cortex, and whole brain against both relative habitat complexity and ecomorph classification. There was no relationship between the relative volume of any brain structure examined and either relevant habitat complexity or ecomorph. However, relevant habitat complexities for each species did not completely match their ecomorph classifications. </p><p>Finally, I tested the levels of behavioral flexibility of three species of <italic>Anolis</italic>, <italic>A. evermanni</italic>, <italic>A. pulchellus</italic>, and <italic>A. cristatellus</italic>, belonging to three distinct ecomorphs, by presenting them with tasks requiring motor and reversal learning. <italic>Anolis evermanni</italic> performed well in both tasks, while <italic>A. pulchellus</italic> required more trials to learn the motor task. Only a single <italic>Anolis cristatellus</italic> was able to perform either task. <italic>Anolis evermanni</italic> displayed lower levels of neophobia than the other species, which may be related to its superior performance.</p><p>In combination, this research suggests that <italic>Anolis</italic> of different ecomorphs display different levels of behavioral flexibility. At the proximate level, this difference in behavioral flexibility cannot be explained by changes in the relative size of the total brain or brain structures associated with cognitive abilities in other taxa. At the ultimate level, the size of the brain and several constituent structures cannot be predicted by habitat complexity. However, behavioral flexibility in certain tasks may be favored by utilization of complex habitats. Flexibility in different tasks is not correlated, rendering broad comparisons to a habitat complexity problematic.</p> / Dissertation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Lizards are considered model organism in ecology, allowing the understanding of patterns and relations between organisms and environment. Tropidurus torquatus is a species with a broad distribution, with populations in different habitats and under diverse environmental pressures. However, the knowledge of diverse aspects of this species are unknown, specially in the subtropical region of the continent. These characteristics make the species in this study excellent to understand questions about geographic variation and environmental variable relations. Our purpose with this study is try to solve some questions that comprehend reproduction and growth from individuals of this specie from two populations, in the Pampa biome, in the south of Brazil. To elucidate the reproductive ecology questions, we collected 315 animals from a population localized in Alegrete/RS, between September of 2007 and August of 2008. The collected animals were dissected and their gonads were analyzed in the laboratory. Growth data were obtained from a study between December 2006 and December 2008, in Santo Antão locality, Santa Maria, Rio Grande do Sul. Every month the individuals were captured, measured, and the difference between the captures were used to calculate the growth rate. The reproductive period was between September and January, with eggs produce from October to January. Males reach the sexual maturity earlier and with smaller size than females. Females produces in average 6,21 eggs per clutch and not produces multiple clutch in the same reproductive period. Temperature, photoperiod, insolation, precipitation and humidity do not affect the reproductive period, but can cause more effect in growth rate. Adult males grow up more than females in summer. Both males and females decrease growth rate when there are less photoperiod, insolation and temperature at the winter. The decrease in growth rate during the winter, has as main consequence there are less animals reproducing in the following season after their birth. The smaller growth rate, late maturation, small reproductive period and eggs incubation are the main characteristics that make the south population different from the others in the tropical climate. Others characteristics like clutch size and eggs size, time of reproduction and offspring size seem to have less variation between populations in this species, and even between species of the genera Tropidurus. The data this study suggest that historic factors and phenotypic plasticity, in response to environment variables, act in this population, in the south of Brazil. / Lagartos são considerados organismos modelos em ecologia, possibilitando o entendimento de padrões e relações entre organismos e ambiente. Tropidurus torquatus é uma espécie amplamente distribuída, com populações vivendo em diversos habitats e sob diferentes pressões ambientais. Apesar disso, diversos aspectos da ecologia da espécie são desconhecidos, principalmente na região subtropical do continente. Essas características tornam a população estudada excelente para o entendimento de questões ligadas a variação geográfica e a relação com as variáveis ambientais. Devido a isso, com esse estudo buscamos resolver algumas questões envolvendo a reprodução e o crescimento dos indivíduos de duas populações, localizadas no Pampa, no sul do Brasil. Para elucidar as questões referentes à ecologia reprodutiva, 315 animais foram coletados, de uma população em Alegrete/RS, mensalmente entre setembro de 2007 e agosto de 2008. Os animais coletados foram dissecados e tiveram suas gônadas analisadas. Dados referentes ao crescimento dos indivíduos foram obtidos de um estudo de captura-recaptura realizado de dezembro de 2006 a dezembro de 2008, na localidade de Santo Antão, Santa Maria, Rio Grande do Sul. Mensalmente, indivíduos eram capturados e a diferença entre sucessivas medidas do comprimento rostro-cloacal utilizadas para calcular a taxa de crescimento. O período reprodutivo estendeu-se de setembro a janeiro, com produção de ovos entre outubro e janeiro. Machos atingiram a maturidade mais precocemente e com menor tamanho em relação às fêmeas. Fêmeas depositaram 6,21 ovos, em média, por ninhada e não há evidencias de produção de ninhadas múltiplas. Temperatura, comprimento do dia, insolação, pluviosidade e umidade não estiveram relacionadas com o período reprodutivo, mas causam grande efeito sobre as taxas de crescimento. Machos adultos cresceram mais do que fêmeas somente no verão. Machos e fêmeas tem o crescimento fortemente restrito pela diminuição do fotoperíodo, insolação e temperatura no inverno. A redução no crescimento durante o inverno tem como principal conseqüência um menor número de animais reproduzindo na estação subseqüente ao seu nascimento. A menor taxa de crescimento, maturação tardia, menor período reprodutivo e de incubação dos ovos são as principais características que diferenciam a população do sul do Brasil de outras de clima tropical em relação aos parâmetros estudados. Outras características, como tamanho da ninhada e dos ovos, época que ocorre a reprodução e tamanho dos filhotes parecem ter menor variação entre populações da espécie e até entre espécies do gênero Tropidurus. Os dados apresentados sugerem a atuação de fatores históricos e da plasticidade fenotípica, frente às variáveis ambientais, nas populações de Tropidurus torquatus do sul do Brasil.

Autotomy (self-induced loss) of body parts has evolved independently as a predator defense mechanism in several major animal phyla. The mechanism among vertebrates, including 13 of the 20 recognized lizard families, is tail autotomy. Its occurrence among the majority of lizard families offers an excellent opportunity to examine the effects of a major selective force on the ecology and evolution of a group of organisms. The research of this study was designed to examine experimentally (i) the function of tail autotomy, (ii) the function of autotomized tail movement, (iii) the energetics of autotomized tail movement, and (iv) the energetic costs of autotomy of an energy-rich tail to reproduction.

No capítulo 1 os principais fatores envolvidos com a distribuição geográfica do gênero Enyalius foram a temperatura média anual, a latitude e a amplitude média da temperatura diurna, indicando uma possível adaptação termal do gênero. A distribuição potencial do grupo refletiu na variação geográfica na morfologia, como demonstrado pelas diferenças no tamanho do corpo e estruturas morfológicas, que foram explicadas por variáveis climáticas, espaciais e estruturais do ambiente. A regra de Allen corroborou com os padrões da variação na morfologia de Enyalius, que foram correlacionados com as condições térmicas e geográficas. Os padrões de variação morfológica também foram associados com cobertura vegetal (e talvez a disponibilidade de água nas diferentes regiões), que pode exercer influência sobre a adaptação morfológica de Enyalius e explicar parte do crescimento diferencial alométrico sobre a vasta área geográfica. A hipótese de adaptação térmica deve ser a base para explicar a distribuição de Enyalius em ambientes de florestas do Brasil. No capítulo 2 estudamos as áreas de distribruição potencial de cada espécie do grupo e encontramos para a maioria delas características ambientais gerais que foram importantes para a ocorrência do gênero nos seus ambientes. A latitude e a amplitude média da temperatura diurna, que se sobreporam na maioria dos modelos de nicho potencial, ao longo da costa brasileira, deve caracterizar a distribuição principal das espécies de Enyalius no Domínio Florestal Atlântico. Isso nos indicou um “padrão geral” de fatores básicos importantes para a ocorrência do grupo neste bioma e que, provavelmente, parte dos nichos ecológicos similares entre algumas espécies, em geral, ocorreram por influência ambiental de ampla magnitude em associação à plasticidade fenotípica das espécies como resposta ecológica adaptativa. No capítulo 3, nós encontramos algumas respostas para as espécies de Enyalius, havendo padrões morfológicos e ambientais específicos associados independentemente da relação filogenética ou da proximidade geográfica em que estas se encontram. Acreditamos que as características ambientais e o uso destas, como recursos, devem influenciar mais sobre a ocorrência das espécies em seus hábitats (pressão de seleção natural) do que por uma questão de inércia filogenética herdada ao grupo. Este estudo também indicou que determinadas mudanças evolutivas nas proporções e no tamanho do corpo das espécies de Enyalius devem estar associadas à divergência de hábitats e suas características e/ou ao uso diferente de substratos entre as espécies de lagartos, e que, consequentemente, necessitam de maiores investigações para o conhecimento das causas das relações ecológicas reveladas aqui. Por fim, os padrões observados sobre a variação morfológica nas espécies de Enyalius devem ser uma conseqüência direta de respostas adaptativas a ação das condições ambientais locais (e.g. seleção natural), o que por sua vez nos revelou grande plasticidade adaptativa das espécies através de suas ecologias em ambientes de continente. / In the first chapter, we saw that the main factors affecting the Enyalius’ geographical distribution were the annual mean temperature, latitude, and the mean diurnal temperature, which indicates a possible thermal adaptation as a base to explain the group distribution. Enyalius distribution was reflected in the morphological geographical variation, as demonstrated by the differences in the body size and morphological structures, which were explained by climatic, spatial and structural variables. The Allen rule was corroborated, as patterns in the morphological variation in Enyalius were correlated with thermal and geographical conditions. The thermal adaptation hypothesis may be the basis to explain Enyalius distribution in different Brazilian forests. In the second chapter we studied the potential distribution areas for each species in the group, and we identified the general environmental characteristics affecting the species occurrence in their habitats, for most species. We suggest that variables such as latitude and mean amplitude of daily temperature along the Brazilian coast overlapped in most of our models, characterizing the main distribution of the species belonging to the genus Enyalius in the Atlantic Forest. In the third chapter, we found that there are morphological and environmental patterns associated with the species, independent of their phylogenetic or geographical relationship. We observed that environmental features seem to be more critical to determine the species occurrence than their evolutionary heritage (e.g. philogenetic inertia). Finally, this study indicated that some evolutionary changes in body size and proportions might be associated to the divergence in habitat requirements and/or the differences in substrate use, which need further investigation. We conclude that the observed morphological variation in Enyalius can be a direct consequence of adaptative responses to local environmental conditions, which demonstrated the high phenotipic plasticity, based on their ecology in environments from mainland.

abstract: Damage to the central nervous system due to spinal cord or traumatic brain injury, as well as degenerative musculoskeletal disorders such as arthritis, drastically impact the quality of life. Regeneration of complex structures is quite limited in mammals, though other vertebrates possess this ability. Lizards are the most closely related organism to humans that can regenerate de novo skeletal muscle, hyaline cartilage, spinal cord, vasculature, and skin. Progress in studying the cellular and molecular mechanisms of lizard regeneration has previously been limited by a lack of genomic resources. Building on the release of the genome of the green anole, <i>Anolis carolinensis</i>, we developed a second generation, robust RNA-Seq-based genome annotation, and performed the first transcriptomic analysis of tail regeneration in this species. In order to investigate gene expression in regenerating tissue, we performed whole transcriptome and microRNA transcriptome analysis of regenerating tail tip and base and associated tissues, identifying key genetic targets in the regenerative process. These studies have identified components of a genetic program for regeneration in the lizard that includes both developmental and adult repair mechanisms shared with mammals, indicating value in the translation of these findings to future regenerative therapies. / Dissertation/Thesis / Doctoral Dissertation Molecular and Cellular Biology 2015