Made available in DSpace on 2016-08-17T15:00:42Z (GMT). No. of bitstreams: 1 Gildevan Nolasco Lopes.pdf: 963789 bytes, checksum: d73e668c2731927697f98bf14d6ea427 (MD5) Previous issue date: 2009-03-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study compared the morphological variation among different populations of Cnemidophorus ocellifer in areas of restinga, and investigated the pattern of sexual dimorphism for this species in this region. Therefore, 130 specimens were collected from four independent areas of restinga in Maranhão Island (Panaquatira, Raposa, Araçagy, and São Marcos Beaches), and measured in the laboratory. Significant morphological differences occurred both for populations and sexes. The populations differed in both body size and shape. The lizards from Raposa showed larger sizes. And the lizards from Panaquatira had more morphological variation, showing shorter limbs and longer trunks. The males of C. ocellifer showed larger body and head, while females had more elongation of the body. The morphological differences were attributed to ecological processes suffered by different groups. / Este estudo comparou a variação morfológica entre populações de Cnemidophorus ocellifer presentes em áreas de restinga, e investigou o padrão de dimorfismo sexual para esta espécie nesta região. Para isso foram coletados 130 espécimes em quatro áreas independentes de restinga na Ilha do Maranhão (Praias de Panaquatira, Raposa, Araçagy e São Marcos) e mensurados em laboratório. Diferenças morfológicas significantes ocorreram tanto para as populações quanto para os sexos. As populações divergiram tanto no tamanho do corpo quanto na forma. Os lagartos da Raposa apresentaram maiores tamanhos. E os lagartos de Panaquatira tiveram maior variação morfológica, apresentando menor comprimento dos membros locomotores e maior alongamento do meio do corpo. Os machos de C. ocellifer apresentaram maior tamanho do corpo e da cabeça, enquanto que as fêmeas apresentaram maior alongamento do corpo. As divergências morfológicas encontradas foram atribuídas a processos ecológicos diferenciados sofridos pelos grupos.

A plasticidade fenotípica do intestino está presente em diferentes grupos de vertebrados e permite ajustes de caráter antecipatório ou de curto prazo na capacidade funcional do intestino frente a flutuações previsíveis e não previsíveis na disponibilidade de alimento no ambiente. No presente trabalho, avaliamos as alterações sazonais na morfologia e na capacidade de oxidação de substratos energéticos no intestino médio de lagartos teiú Tupinambis merianae. A resposta ao jejum associado à depressão metabólica na dormência de inverno foi contrastada com as alterações após 20 dias de jejum na fase ativa. Grupos de animais jovens foram mortos em diferentes fases do primeiro ciclo anual e o intestino médio foi removido e pesado. Amostras do terço proximal do órgão foram transferidas para frascos contendo formaldeído tamponado e o restante do tecido foi picotado e amostras aleatórias foram congeladas em N2 líquido e transferidas para freezer -80 oC. Variáveis morfológicas foram analisadas em cortes histológicos de 5 μm de espessura utilizando-se o método estereológico. O teor de água e o de proteína solúvel e total foi medido nas amostras por meio de ensaios padrão; as atividades máximas de enzimas foram medidas por espectrofotometria em condições saturantes de substrato e cofatores. No outono, a massa relativa do intestino é 1,04% e diminui 23% durante a dormência, junto a uma redução na densidade de volume da mucosa e de superfície do epitélio, da altura máxima dos vilos e do conteúdo protéico total. O epitélio altera sua conformação estrutural, passando de colunar simples para pseudo-estratificado, sugerindo intensa atividade proliferativa. Após o despertar na primavera, há um aumento de mais de duas vezes da massa do intestino, com um aumento da densidade de superfície epitelial e, possivelmente, do comprimento e/ou diâmetro do órgão. Em animais submetidos ao jejum, a massa intestinal relativa diminui 49% em relação a animais alimentados, porém, a atrofia da mucosa é menos intensa e o epitélio é mais preservado, além de um aumento da espessura da túnica muscular. O tecido possui elevado potencial para o uso de diferentes substratos energéticos e o tipo preferencial seria regulado em função do estado nutricional e metabólico do animal. As enzimas glicolíticas HK, PK e LDH não variam ao longo do ciclo anual, assim como a transaminase AspAT. Por outro lado, a GDH, enzima da oxidação de aminoácidos, a HOAD, enzima da β- oxidação lipídica e a CS, indicadora da capacidade aeróbia mitocondrial estão fortemente inibidas na dormência, acompanhando a depressão metabólica no animal. Em animais submetidos ao jejum na primavera, todas as enzimas tiveram suas atividades reduzidas e, em consonância com os dados da morfologia do tecido, os ajustes na capacidade funcional do órgão aparentemente se dão de maneira diferente em relação ao jejum associado à dormência sazonal, em função do caráter previsível e da existência de uma fase antecipatória neste fenômeno. / The gut phenotypic plasticity is widely documented in the vertebrates and would allow to either short term or anticipatory adjustments in the organ functional capacity, to cope with unpredictable and periodic changes of food availability in the environment. This study investigates seasonal changes of morphology and in the capacity for substrate oxidation in the midgut of the tegu lizard Tupinambis merianae, associated with prolonged fasting and metabolic depression in winter months. In addition, the pattern of change was compared with the adjustments induced by 20 days of fasting in spring active animals. Groups of young lizards were killed in distinct phases during the first annual cycle and the midgut was quickly excised and weighted. Tissue samples were removed from the organ proximal third and preserved in fixative solution for histology. The remaining tissue was cut in small pieces and aliquots were frozen in liquid N2 and stored at -80oC for the assays. The morphological changes were analyzed in 5μm thick slices using stereological methods. The content of water and of total and soluble proteins were measured using standard assays, and maximum activities of metabolic enzymes were measured by espectrophotometry. The mid-gut mass is 1.04% of body mass in autumn activity and decreases 23% during winter dormancy, combined with a reduction of mucosal volume and surface densities, of villus maximal height and of total protein content. The epithelial cells change conformation from columnar to pseudo-stratified, suggesting intense proliferative activity during dormancy. Later in spring activity, the mid-gut mass increases to 1.64% combined with an increase of epithelial surface density and possibly of midgut lenght and/or diameter. Atrophy during fasting was higher in active lizards, 49% in relation to fed animals, the mucosal density however is more preserved than during dormancy and the muscle layer increases thickness. High levels of enzyme activities suggest a potential to obtain energy from different substrates and the regulatory mechanisms of fuel selection would act as a function of the physiological context. HK, PK and LDH, and AspAT, acting on pathways of glucose and amino-acid oxidation respectively, do not change during the annual cycle, whereas GDH and HOAD (amino-acid and fatty acid oxidation respectively), and CS (indicator of mitochondrial aerobic capacity) are strongly inhibited in dormant and arousing animals. Fasting during spring activity caused all enzymes to be inhibited and this effect, together with large tissue atrophy, suggest that in the short term fasting the regulatory mechanisms allow to save glucose for glucose-dependent tissues, besides contributing to energy spare at the whole body level.

Populärmusiken existerar idag på sociala medieplattformar där vem som helst kanuttrycka sig – och använda sig av alla andras material. Studien berörmeningsskapande inom konvergenskulturen kring det australienska bandet KingGizzard & The Lizard Wizard. Arbetet fokuserar på rörlig bild och musik inomden kulturella kontexten. Syftet med studien är att bidra med förståelse för hurmedieproduktioners kommunikationssätt samspelar och formas av nämndakonvergenskulturen. Studien gjordes genom multimodala analyser avaudiovisuellt material på en remix av ett fan till bandet samt material från bandetsjälva. Resultatet visade att betydelsepotentialen är kopplat till teman omdigitalisering och undergång som inbjuder fans till att vara med och delta.

No description available.

The European green lizard, Lacerta viridis, is in the Bohemia region stated as critically endangered species. Populations in this region are located beyond the northern border of continuous range of this species and are closely related to the "riverine phenomenon", and deeply engorged river valleys. The chosen locality in Tiché údolí is a subject to a long-term conservational management aimed to strengthen and maintain abundance of the local population. This management is a direct output of a previous study of this population performed in years 1995-1997. Main goal of the presented study is to compare current population characteristics with the older study. The locality has been visited 119 times in years from 2011 to 2014. The studied population now displays higher abundance and inhabits a larger area. The author also performed a spatial analysis of the places with presence of an observed individual in order to determine and evaluate significance of the chosen abiotic factors for habitat discrimination. The results indicate that positive discrimination is based on the presence of a rock debris and a hiding place. Strongest factors towards negative discrimination were high percentages of grass and high vegetation coverage. This study also contains and discusses ecological, ethological and...

Lagartos teiú eclodem no verão e enfrentam o desafio de crescer e armazenar substratos em um curto período de tempo, antes do início do período de jejum e depressão metabólica (≈80%) a temperaturas amenas durante o inverno (≈17 °C). No despertar, o aumento do metabolismo e a reperfusão de órgãos favoreceriam a ocorrência de estresse oxidativo. Na primeira parte do presente estudo investigou−se os ajustes que compatibilizam as demandas em teiús neonatos, especialmente na pré-hibernação, por meio da gravação do comportamento em vídeo e da análise da massa dos corpos gordurosos abdominais e do nível plasmático de corticosterona (CORT) durante o primeiro ciclo anual. No início do outono a massa corpórea dos teiús foi 27 g e o comprimento rostro−cloacal 9,3 cm e aumentaram 40% e 20%, respectivamente, ao longo do outono, enquanto que as taxas diminuíram progressivamente até atingirem o valor zero no início do inverno. Na primavera, a massa corpórea dos teiús aumentou 80% em relação ao despertar e dobrou em relação ao final do verão; o comprimento acumulou um aumento de 27% em relação ao final do verão. A massa relativa dos corpos gordurosos foi 3,7% no início do outono e diminuiu nos meses subsequentes; no despertar, este estoque acumulou uma perda de 63% da sua massa. No início do outono 74% dos teiús estavam ativos por 4,7 h e permaneceram 2 h assoalhando diariamente; ao longo do outono o número de animais ativos e o tempo em atividade diminuíram até que todos se tornaram inativos. Na primavera 83% dos teiús estavam ativos por 7 h e permaneceram 4 h assoalhando. Um padrão sazonal similar foi observado na atividade locomotora e na alimentação. No outono, a alimentação cessou antes da atividade diária e os teiús tornaram−se afágicos algumas semanas antes da entrada em hibernação. Os maiores níveis de CORT foram observados no início do outono, reduzindo progressivamente até valores 75 e 86% menores na dormência e despertar, respectivamente; na primavera os níveis de CORT foram 32% menores em comparação com o início do outono. Este padrão sugere um papel da CORT nos ajustes que promovem a ingestão de alimento e a deposição de substratos energéticos no outono. A redução da atividade geral no final do outono contribuiria para a economia energética e manutenção da massa corpórea, apesar da redução da ingestão de alimento. O curso temporal das alterações fisiológicas e comportamentais em neonatos reforça a ideia de que a dormência sazonal nos teiús é o resultado da expressão de um ritmo endógeno. Na segunda parte do estudo foi investigada a hipótese de que ocorreriam ajustes das defesas antioxidantes durante a hibernação, em antecipação ao despertar. Foram analisados marcadores de estresse oxidativo e antioxidantes em vários órgãos de teiús em diferentes fases do primeiro ciclo anual. A CS, um indicador do potencial oxidante, não variou no fígado e foi menor no rim e no pulmão na hibernação. As enzimas antioxidantes revelaram (1) um efeito abrangente de redução das taxas na hibernação e despertar; por exemplo, GR e CAT foram menores em todos órgãos analisados e a GST tendeu a diminuir no fígado e no rim, embora constante no coração e no pulmão. A G6PDH no fígado e no rim não variou. (2) No fígado, a GST, a Se−GPX e o teor de TBARS foram maiores na atividade de outono em relação à primavera e a Se−GPX permaneceu elevada na hibernação. (3) No fígado, a SOD foi maior na hibernação e despertar em relação ao outono e a Mn−SOD seguiu este padrão. Em contraste, no rim, coração e pulmão a SOD foi menor na hibernação e as taxas se recuperaram no coração e pulmão no despertar. A Mn−SOD seguiu este padrão no pulmão. A concentração e o estado redox da glutationa não variaram no fígado, rim e coração; no pulmão o teor de Eq−GSH e GSH foi menor na hibernação, com tendência à recuperação no despertar. O teor de PC no rim foi maior na hibernação e diminuiu no despertar. No fígado, as alterações no jejum se assemelham às sazonais, como sugerem a inibição da CAT e GR e aumento da Se−GPX. Os efeitos do jejum na primavera no rim diferem dos efeitos sazonais, como sugerem a redução do teor de Eq−GSH e GSH e o aumento da razão GSSG:GSH, a redução da G6PDH e o aumento de PC. No conjunto, houve um efeito predominante de redução das taxas enzimáticas na hibernação e no despertar, exceto pelas taxas aumentadas da SOD e Se−GPX no fígado e pela recuperação da SOD no coração e da GR, SOD e Mn−SOD no pulmão no despertar. As elevadas taxas das enzimas antioxidantes no teiú em comparação a outros ectotermos e a ausência de evidências de estresse oxidativo no despertar sugerem que a atividade enzimática remanescente é suficiente para prevenir danos aos tecidos face às flutuações do metabolismo / The tegu lizards hatch during the summer, when they face the challenge of growing and storing substrates during a short time before going into fasting and metabolic depression (≈80% at 17 °C) during winter. The reactivation of metabolism and of blood perfusion during arousal could favor the occurrence of oxidative stress in the tissues. The first part of his study investigated adjustments which potentially conciliate energy demands in neonatal tegus, particularly during pre-hibernation, by video recording of animal behavior and by measuring the mass of fat bodies and levels of plasma corticosterone (CORT) during the annual cycle. In the early autumn the body mass of the tegu was 27 g and the rostro−cloacal length was 9.3 cm, which increased 40% and 20%, respectively, while the rates decreased progressively until reach zero in winter. In spring activity body mass increased 80% in relation to values during arousal and duplicated in relation to late summer. The fat bodies mass relative to body mass was 3.7% in early autumn, and decreased during the subsequent months accumulating a mass loss of 63% during arousal. In early autumn, 74% of the tegus were active for 4.7 h and they basked for 2 h daily; during the autumn the number of animals and the time spent in activity decreased until they become totally inactive. In spring 83% of the tegus were active for 7 h and they basked for 4 h daily. Similar seasonal pattern was observed in the locomotory and feeding activities. In the autumn, feeding was interrupted prior to the interruption of daily activity and the tegus were aphagic a few weeks before the entry into hibernation. The CORT level was the highest in early autumn and reduced progressively to 75% and 86% during winter and arousal in early spring, respectively; later during spring the levels were 32% lower than the autumn levels. These changes suggest a role of CORT in the adjustments which promote food intake and substrate storage during the autumn. Despite a reduced food intake, the widespread decrease of daily activities in late autumn would contribute to energy saving and body mass maintenance. The time course of physiological and behavioral changes in neonates reinforces the idea of an endogenous rhythm underlying seasonal dormancy in the tegu. The second part of this study investigated the hypothesis of adjustments in antioxidant system preparatory to the moment of arousal by the analysis of markers of oxidative stress and of antioxidants in several organs of neonatal tegus, during different phases of the annual cycle and during starvation in the spring. The Vmax of CS, an indicator of the oxidative potential, did not vary in the liver and was smaller in the kidney and lung of dormant tegus. The antioxidant enzymes revealed (1) a widespread effect of lowering rates during dormancy and arousal; for instance, GR and CAT were lower in all organs examined and GST had a tendency to be lower in the liver and in the kidney tissues, although it was constant in the heart and in the lung. (2) In the liver, GST and Se-GPX, and the levels of TBARs were higher in the autumn than in the spring activity. (3) In the liver, SOD was higher during dormancy and arousal in relation to the autumn, and Mn−SOD followed this pattern. Contrastingly, SOD in the kidney, heart and lung was lower during dormancy, and rates recovered in the heart and lung during arousal before food intake. The Mn-SOD followed this pattern in the lung. The glutathione concentration and the redox balance did not change in the liver, kidney and heart; in the lung, the levels of Eq−GSH and GSH were lower and had a tendency to increase during arousal. Importantly, carbonyl proteins were increased in the kidney during dormancy and recovered during arousal. The effects of starvation during spring differed of those of fasting during winter in the kidney, as shown by the lower Eq−GSH levels and increased GSSG:GSH ratio, the lower G6PDH, and the increased carbonyl proteins. In the liver, changes during starvation followed seasonal patterns, as shown by increased Se-GPX, and decreased CAT and GR, together indicating a consistent effect exerted by interruption of food intake. The high rates of antioxidant enzymes in neonatal tegus compared with other ectotherms, and the absence of evidence of oxidative stress at arousal suggest that remaining enzyme activities are sufficient to prevent tissue damage that could be caused by the metabolic fluctuations during the annual cycle in the tegu

Fauna conservation outside protected areas can make an important complementary contribution to conservation within reserves. This thesis aimed to contribute new information and analytical frameworks to the science of fauna conservation in human-modified landscapes. Two approaches were used: (1) empirical data collection and analysis, and (2) the discussion and development of conceptual landscape models. ¶ Empirical work focused on lizard distribution patterns in two production landscapes in southeastern Australia. Lizards were targeted because ectotherms are frequently neglected by conservation biologists. The “Nanangroe grazing landscape” was used for sheep and cattle grazing. In this landscape, approximately 85% of pre-European woodland cover had been cleared, and understorey vegetation was sparse. Lizards were surveyed at 16 landscape units, which were stratified by aspect, topographic position and amount of tree cover. Each landscape unit contained three sites, and each site contained three plots. Regression modelling showed that different species responded differently to their environment. For example, the four-fingered skink (Carlia tetradactyla) and Boulenger’s skink (Morethia boulengeri) were more likely to occur at woodland sites with northerly aspects, whereas the striped skink (Ctenotus robustus) and olive legless lizard (Delma inornata) were more likely to inhabit sites with a simple microhabitat structure. Statistical analysis further showed that the habitat attributes that lizards were related to varied continuously through space, and over different spatial scales. For example, invertebrate abundance (a proxy for food availability) varied most strongly over tens of metres, whereas the amount of grass cover varied most strongly over hundreds to thousands of metres. Thus, work at Nanangroe revealed spatially complex patterns of lizard occurrence and habitat variables. ¶ The “Tumut plantation landscape” was a spatial mosaic of native eucalypt (Eucalyptus) forest patches embedded within a plantation of the introduced radiata pine (Pinus radiata). In this landscape, thirty sites were surveyed for lizards. Sites were stratified by forest type and patch size, and included eucalypt patches, pine sites, and extensive areas of eucalypt forest adjacent to the plantation. Regression modelling showed that lizard species responded to various habitat attributes, including elevation, the amount of eucalypt forest within 1 km of a site, invertebrate abundance and ground cover. Variables related to habitat fragmentation often were significant predictors of lizard occurrence. However, work at Tumut suggested that important additional insights into lizard distribution patterns could be obtained by considering variables related to food and shelter resources, and climatic conditions. ¶ The Nanangroe and Tumut landscapes were in close proximity, but together spanned an altitudinal gradient of 900 m. An investigation of changes in lizard community composition with altitude showed that (1) only one species was common to Nanangroe and Tumut, (2) different species had different altitudinal preferences, and (3) ecologically similar species replaced one another with increasing altitude. These results highlighted that even in highly modified landscapes, natural gradients (such as climate) can play an important role in shaping animal assemblage composition and species distribution patterns. ¶ Empirical work suggested that, in some landscapes, the frequently used “fragmentation model” is a relatively weak conceptual basis for the study of animal distribution patterns. The fragmentation model implicitly assumes that “habitat patches” can be defined unequivocally across many species, and that patches are located within a relatively inhospitable matrix. Where these assumptions are breached, conservation guidelines arising from the fragmentation model may be too simplified. In spatially complex production landscapes, it may be more appropriate to maintain habitat heterogeneity at multiple spatial scales than to focus solely on the management of large, pre-defined patches. ¶ Given the potential limitations of the fragmentation model, a new, more holistic landscape model was developed. The “continuum model” was derived from continuum theory as developed for plant ecology. The continuum model recognises (1) spatial continua of environmental variables, and (2) species’ individualistic responses to these variables. For animals, key environmental variables may be related to the availability of food, shelter, sufficient space, and suitable climatic conditions. Unlike the fragmentation model, the continuum model is inherently process-based and thus may help to link the perceived gap between patterns and processes in landscape ecology. ¶ Three general conclusions arise from this thesis: 1. Some heterogeneous production landscapes support many native species, and therefore represent important conservation opportunities. 2. In some modified landscapes, the fragmentation model does not capture the complexity of animal distribution patterns. In those landscapes, conservation recommendations derived from the fragmentation model may be overly simplistic. 3. The continuum model may be a useful extension of the fragmentation model. It provides a process-based conceptual basis for empirical work on animal distribution patterns.

In this thesis, I investigate the phylogeny and evolution of Lerista, a clade of more than 75 species of scincid lizards, distributed in arid, semi-arid, and seasonally dry habitats throughout Australia. Among extant tetrapods, Lerista is exceptional in comprising a large number of closely-related species displaying prodigious variability of body form; several species possessing well-developed, pentadactyl limbs resemble typical non-fossorial scincids in body proportions, while many other species exhibit varying degrees of limb reduction and body elongation, including two that are highly elongate and entirely limbless. The extensive variation in limb morphology observed among species, incorporating at least 20 distinct phalangeal configurations, has prompted some authors to identify Lerista as the best available model for studying limb reduction in squamates. Nonetheless, lack of a well-resolved phylogeny has impeded investigation of the pattern and mode of limb reduction and loss within the clade. The primary goal of my research was to furnish a comprehensive phylogenetic hypothesis for Lerista, enabling more sophisticated study of the evolution of limb morphology and body form in this clade than has previously been possible. A recent phylogenetic analysis of mitochondrial DNA sequences for a series of Australian Sphenomorphus group scincids (including two species of Lerista) recovered several well-supported, major clades, although these were generally separated by relatively short branches associated with low support values. Applying a recently described methodology for inferring lineage-level polytomies, I use ATP synthetase-β subunit intron sequences and the existing mitochondrial DNA data set (with sequences for additional taxa) to assess the hypothesis that the poorly resolved basal relationships within the Australian Sphenomorphus group are a consequence of the major clades having originated essentially simultaneously. Phylogenetic analyses of the separate mitochondrial DNA and intron sequence data reveal a number of congruent clades, however, the relationships among these clades indicated by the two data sets are generally incongruent. Although this may be partly ascribed in to error in estimating phylogenetic relationships due to insufficient data, some incongruence is evident when uncertainty in inferred relationships is allowed for. Moreover, the congruent clades are typically separated by very short branches, several having a length insignificantly different from zero. These results suggest that initial diversification of Australian Sphenomorphus group scincids was rapid relative to the substitution rates of the mitochondrial DNA and intron fragments considered, if not essentially simultaneous. The pattern and rate of limb reduction in Lerista are investigated, employing a nearly complete phylogeny inferred from nucleotide sequences for a nuclear intron and six mitochondrial genes. Ancestral digit configurations reconstructed assuming this phylogeny indicate at least ten independent reductions in the number of digits from a pentadactyl condition, including four independent losses of all digits, three from pentadactyl or tetradactyl conditions. At the highest rate, complete loss of digits from a pentadactyl condition is estimated to have occurred within no more than 3.6 million years. Patterns of digit loss for the manus and pes are consistent with selection for preserving hindlimb utility as the limbs are reduced, and suggest that intermediate digit configurations exhibited by extant species do not represent transitory stages in a continuing process of limb reduction. An increase in the relative length of the body is demonstrated to precede digit loss in lineages experiencing substantial reduction of the limbs, supporting the hypothesis that limb reduction and loss is a consequence of the adoption of lateral undulation as a significant locomotory mode. However, less extensive limb reduction may proceed in the absence of body elongation, perhaps due to a decrease in absolute body size. The exceptionally high frequency and rate of limb reduction in Lerista emphasise the potential for rapid and dramatic evolutionary transformation of body form in squamates. The substantial divergence of relative limb and body length evident within Lerista is more readily explained by the correlated progression model of phenotypic transformation than the independent blocks model. At each step in the attainment of a limb-reduced, elongate body form, alterations to the relative length of the limbs are accompanied by changes in relative snout-vent length (or vice versa) enabling the maintenance of locomotory ability. Nonetheless, some dissociation of hindlimb reduction and body elongation is possible, emphasising the potentially variable intensity of functional constraints and, accordingly, that the independent blocks model and correlated progression are extremes of a continuum of models (each invoking a different degree of functional integration) and do not describe discrete categories of phenotypic change. An increase in the extent of seasonally dry and arid habitats coincident with the origination of Lerista would have facilitated limb reduction and body elongation by furnishing an environment conducive to the adoption of fossorial habits, however, trends toward a limbless, highly elongate body form may be attributed primarily to the very low probability of re-elaborating reduced limbs. Such asymmetry in the probabilities of possible phenotypic changes may be a significant cause of evolutionary trends resulting in the emergence of higher taxa. / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

In this thesis, I investigate the phylogeny and evolution of Lerista, a clade of more than 75 species of scincid lizards, distributed in arid, semi-arid, and seasonally dry habitats throughout Australia. Among extant tetrapods, Lerista is exceptional in comprising a large number of closely-related species displaying prodigious variability of body form; several species possessing well-developed, pentadactyl limbs resemble typical non-fossorial scincids in body proportions, while many other species exhibit varying degrees of limb reduction and body elongation, including two that are highly elongate and entirely limbless. The extensive variation in limb morphology observed among species, incorporating at least 20 distinct phalangeal configurations, has prompted some authors to identify Lerista as the best available model for studying limb reduction in squamates. Nonetheless, lack of a well-resolved phylogeny has impeded investigation of the pattern and mode of limb reduction and loss within the clade. The primary goal of my research was to furnish a comprehensive phylogenetic hypothesis for Lerista, enabling more sophisticated study of the evolution of limb morphology and body form in this clade than has previously been possible. A recent phylogenetic analysis of mitochondrial DNA sequences for a series of Australian Sphenomorphus group scincids (including two species of Lerista) recovered several well-supported, major clades, although these were generally separated by relatively short branches associated with low support values. Applying a recently described methodology for inferring lineage-level polytomies, I use ATP synthetase-β subunit intron sequences and the existing mitochondrial DNA data set (with sequences for additional taxa) to assess the hypothesis that the poorly resolved basal relationships within the Australian Sphenomorphus group are a consequence of the major clades having originated essentially simultaneously. Phylogenetic analyses of the separate mitochondrial DNA and intron sequence data reveal a number of congruent clades, however, the relationships among these clades indicated by the two data sets are generally incongruent. Although this may be partly ascribed in to error in estimating phylogenetic relationships due to insufficient data, some incongruence is evident when uncertainty in inferred relationships is allowed for. Moreover, the congruent clades are typically separated by very short branches, several having a length insignificantly different from zero. These results suggest that initial diversification of Australian Sphenomorphus group scincids was rapid relative to the substitution rates of the mitochondrial DNA and intron fragments considered, if not essentially simultaneous. The pattern and rate of limb reduction in Lerista are investigated, employing a nearly complete phylogeny inferred from nucleotide sequences for a nuclear intron and six mitochondrial genes. Ancestral digit configurations reconstructed assuming this phylogeny indicate at least ten independent reductions in the number of digits from a pentadactyl condition, including four independent losses of all digits, three from pentadactyl or tetradactyl conditions. At the highest rate, complete loss of digits from a pentadactyl condition is estimated to have occurred within no more than 3.6 million years. Patterns of digit loss for the manus and pes are consistent with selection for preserving hindlimb utility as the limbs are reduced, and suggest that intermediate digit configurations exhibited by extant species do not represent transitory stages in a continuing process of limb reduction. An increase in the relative length of the body is demonstrated to precede digit loss in lineages experiencing substantial reduction of the limbs, supporting the hypothesis that limb reduction and loss is a consequence of the adoption of lateral undulation as a significant locomotory mode. However, less extensive limb reduction may proceed in the absence of body elongation, perhaps due to a decrease in absolute body size. The exceptionally high frequency and rate of limb reduction in Lerista emphasise the potential for rapid and dramatic evolutionary transformation of body form in squamates. The substantial divergence of relative limb and body length evident within Lerista is more readily explained by the correlated progression model of phenotypic transformation than the independent blocks model. At each step in the attainment of a limb-reduced, elongate body form, alterations to the relative length of the limbs are accompanied by changes in relative snout-vent length (or vice versa) enabling the maintenance of locomotory ability. Nonetheless, some dissociation of hindlimb reduction and body elongation is possible, emphasising the potentially variable intensity of functional constraints and, accordingly, that the independent blocks model and correlated progression are extremes of a continuum of models (each invoking a different degree of functional integration) and do not describe discrete categories of phenotypic change. An increase in the extent of seasonally dry and arid habitats coincident with the origination of Lerista would have facilitated limb reduction and body elongation by furnishing an environment conducive to the adoption of fossorial habits, however, trends toward a limbless, highly elongate body form may be attributed primarily to the very low probability of re-elaborating reduced limbs. Such asymmetry in the probabilities of possible phenotypic changes may be a significant cause of evolutionary trends resulting in the emergence of higher taxa. / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

Reptiles are polyphyletic, and previous studies of renal anatomy and physiology in reptiles have covered a wide diversity of species of different phylogeny and habitat. To date, no study has examined the renal morphology and function of a group of closely related reptiles from different environments, yet this design has a number of advantages. Firstly, phylogenetic effects are reduced while adaptive specialisations in renal function or structure can be elucidated, and secondly, the variation in renal form and function between closely related species may be quantified in an effort to appreciate better the variation between more distantly related species. In this thesis, kidney morphology and renal function were studied in three Western Australian agamid lizards inhabiting environments differing in the availability of water. These key species were Pogona minor, Ctenophorus nuchalis and Ctenophorus salinarum. The renal anatomy of the three key lizards was characterised by determining glomerular diameter, volume density, surface area and number in each. Allometric relationships between kidney, colon and body mass were investigated in these and an additional 11 species of agamid lizard. Patterns of response to osmotic challenge were recorded by measuring renal variables such as urine flow rate, glomerular filtration rate and fractional reabsorption of filtrate among the three key species, and concurrent measurements of circulating arginine vasotocin in P. minor and C. nuchalis allowed the response of this hormone to homeostatic imbalance in these species to be gauged. The gross morphology and the glomerular characteristics of the kidneys was remarkably similar between species. Glomerular number and other characters varied as a function of body size rather than species, contrasting with reports in the literature suggesting that a given species has a particular number of glomeruli. ... Thus, kidney morphology is constrained among species and the response of each species to osmotic perturbation is similar. However, the mechanisms underlying antidiuresis and the hormonal control of this process differ subtly between species, and there is some evidence to suggest that P. minor is more adapted to a mesic environment than the other two lizards examined in this study. The hypothesis that renal form and function reflect the environment in which a lizard lives therefore receives partial support, although the reptilian bauplan is able to mitigate many of the forces that could potentially lead to renal specialisation.