Dissertations / Theses: 'Reptile'

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Bernarde, Paulo Sérgio [UNESP]. "Composição faunística, ecologia e história natural de serpentes em uma região no sudoeste da Amazônia, Rondônia, Brasil." Universidade Estadual Paulista (UNESP), 2004. http://hdl.handle.net/11449/106551.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Em Espigão do Oeste (Rondônia) foi registrada uma riqueza de 56 espécies de serpentes, apresentando uma maior similaridade faunística com a Usina Hidrelétrica de Samuel (RO), localizada relativamente próximo da área de estudo. As serpentes mais comuns foram Liophis reginae (18,6% do total), Oxyrhopus melanogenys (8,4%), Chironius exoletus (6%), Boa constrictor (5,8%), Dipsas catesbyi (5,6%) e Drymarchon corais (5,6%). A freqüência de Bothrops atrox, o viperídeo mais abundante na Amazônia, foi considerado baixo (2%). Um menor número de serpentes foi registrado durante os meses mais secos (junho - agosto), que também coincidiu com a menor ocorrência de anfíbios anuros. Observando a freqüência de potenciais presas (anuros, lagartos, marsupiais e roedores) sazonalmente registrada através das armadilhas de interceptação e queda (todos os grupos), procura limitada por tempo (lagartos dormindo sobre a vegetação à noite e anuros em atividade de vocalização), observa-se que houve disponibilidade de alimento ao longo do ano, embora cada grupo tenha ocorrido em diferentes níveis e picos de abundância. Os principais tipos de presas utilizados pelas serpentes nesta comunidade são lagartos (55,3% das espécies), seguido de anuros (48,2%), mamíferos (26,8%), aves (12,5%) e serpentes (12,5%). Uma análise de agrupamento utilizando dados de tamanho (comprimento rostro-cloacal) e de utilização de recursos (hábitos alimentares, período e substrato de forrageio) originou oito grupos (guildas) de serpentes. Nesta análise de agrupamento, foram reunidas tanto espécies próximas como distantes filogeneticamente, denotando a importância de fatores históricos e ecológicos na estruturação desta comunidade. Maior número de espécies de serpentes foi encontrado dentro de florestas, em relação aos ambientes de pastagens, demonstrando o decréscimo de espécies...
A snake richness of as much as 56 species was recorded at Espigão do Oeste (Rondônia). This makes the studied area faunistically similar to the Samuel Hydroelectric Plant (Rondônia), which is located close to it. The commonest snakes were Liophis reginae (18.6% of the total), Oxyrhopus melanogenys (8.4%), Chironius exoletus (6%), Boa constrictor (5.8%), Dipsas catesbyi (5.6%) and Drymarchon corais (5.6%). It is noticed a low frequency of Bothrops atrox (2%), the most abundant viperid in the Amazon. A lesser number of snakes was recorded during the driest months (from June to August), when there was a lesser occurrence of anuran amphibians as well. By seasonally observing the frequency of potential prey (anurans, lizards, marsupials and rodents), recorded by means of pitfall traps with drift fences (all groups) and time constrained search (lizards sleeping on the vegetation at night and calling anurans), it is noticed that there was availability of food supply throughout the year, although each group occurred at different abundance levels and peaks. Lizards (55.3% of the species), followed by anurans (48.2%), mammals (26.8%), birds (12.5%) and snakes (12.5%), are the main prey for the snakes in this community. A cluster analysis was carried out to produce a dendrogram with information on size (snout-vent length), feeding habits, period and forage substratum. Eight guilds of snakes were formed, according to the similarities in the use of resources. This cluster analysis grouped together species that, phylogenetically, were either close or distant, in order to mark the importance of historical and ecological factors to the structuring of this community. Most snake species were found throughout forested lands more than on pasture lands, showing that the weaker the vegetal structure, the lesser the number of species. Among the causes that may be enhancing or restraining the occurrence...(Complete abstract click electronic access below)

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2

Bernarde, Paulo Sérgio. "Composição faunística, ecologia e história natural de serpentes em uma região no sudoeste da Amazônia, Rondônia, Brasil /." Rio Claro : [s.n.], 2004. http://hdl.handle.net/11449/106551.

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Orientador: Augusto Shinya Abe
Banca: Marcio Roberto Costa Martins
Banca: Otavio Augusto Vuolo Marques
Banca: Julio Cesar de Moura Leite
Banca: Francisco Luiz Franco
Resumo: Em Espigão do Oeste (Rondônia) foi registrada uma riqueza de 56 espécies de serpentes, apresentando uma maior similaridade faunística com a Usina Hidrelétrica de Samuel (RO), localizada relativamente próximo da área de estudo. As serpentes mais comuns foram Liophis reginae (18,6% do total), Oxyrhopus melanogenys (8,4%), Chironius exoletus (6%), Boa constrictor (5,8%), Dipsas catesbyi (5,6%) e Drymarchon corais (5,6%). A freqüência de Bothrops atrox, o viperídeo mais abundante na Amazônia, foi considerado baixo (2%). Um menor número de serpentes foi registrado durante os meses mais secos (junho - agosto), que também coincidiu com a menor ocorrência de anfíbios anuros. Observando a freqüência de potenciais presas (anuros, lagartos, marsupiais e roedores) sazonalmente registrada através das armadilhas de interceptação e queda (todos os grupos), procura limitada por tempo (lagartos dormindo sobre a vegetação à noite e anuros em atividade de vocalização), observa-se que houve disponibilidade de alimento ao longo do ano, embora cada grupo tenha ocorrido em diferentes níveis e picos de abundância. Os principais tipos de presas utilizados pelas serpentes nesta comunidade são lagartos (55,3% das espécies), seguido de anuros (48,2%), mamíferos (26,8%), aves (12,5%) e serpentes (12,5%). Uma análise de agrupamento utilizando dados de tamanho (comprimento rostro-cloacal) e de utilização de recursos (hábitos alimentares, período e substrato de forrageio) originou oito grupos (guildas) de serpentes. Nesta análise de agrupamento, foram reunidas tanto espécies próximas como distantes filogeneticamente, denotando a importância de fatores históricos e ecológicos na estruturação desta comunidade. Maior número de espécies de serpentes foi encontrado dentro de florestas, em relação aos ambientes de pastagens, demonstrando o decréscimo de espécies...(Resumo completo, clicar acesso eletrônico abaixo)
Abstract: A snake richness of as much as 56 species was recorded at Espigão do Oeste (Rondônia). This makes the studied area faunistically similar to the Samuel Hydroelectric Plant (Rondônia), which is located close to it. The commonest snakes were Liophis reginae (18.6% of the total), Oxyrhopus melanogenys (8.4%), Chironius exoletus (6%), Boa constrictor (5.8%), Dipsas catesbyi (5.6%) and Drymarchon corais (5.6%). It is noticed a low frequency of Bothrops atrox (2%), the most abundant viperid in the Amazon. A lesser number of snakes was recorded during the driest months (from June to August), when there was a lesser occurrence of anuran amphibians as well. By seasonally observing the frequency of potential prey (anurans, lizards, marsupials and rodents), recorded by means of pitfall traps with drift fences (all groups) and time constrained search (lizards sleeping on the vegetation at night and calling anurans), it is noticed that there was availability of food supply throughout the year, although each group occurred at different abundance levels and peaks. Lizards (55.3% of the species), followed by anurans (48.2%), mammals (26.8%), birds (12.5%) and snakes (12.5%), are the main prey for the snakes in this community. A cluster analysis was carried out to produce a dendrogram with information on size (snout-vent length), feeding habits, period and forage substratum. Eight guilds of snakes were formed, according to the similarities in the use of resources. This cluster analysis grouped together species that, phylogenetically, were either close or distant, in order to mark the importance of historical and ecological factors to the structuring of this community. Most snake species were found throughout forested lands more than on pasture lands, showing that the weaker the vegetal structure, the lesser the number of species. Among the causes that may be enhancing or restraining the occurrence...(Complete abstract click electronic access below)
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Bratt, Ian (Ian R. ). "Reptile : a distributed ILP compiler." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/34372.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.
Includes bibliographical references (p. 69-71).
The past few years witnessed a dramatic shift in computer microprocessor design. Rather than continue with the traditional pursuit of increased sequential program performance, industry and academia alike chose to focus on distributed, multi-core designs. If multi-core designs are to maintain the decades-long trend of increased single threaded performance, compiler technology capable of converting a single threaded program into multiple programs must be developed. In this thesis I present the Raw Explicitly Parallel Tile Compiler (Reptile), a compiler targeting the RAW computer architecture capable of converting a single threaded program into multiple threads communicating at the instruction operand granularity. On applications with sufficient amounts of parallelism Reptile has generated code which, on the Raw processor, achieves a speedup of as much as 2.3x (cycle to cycle) over an Athlon64.
by Ian Bratt.
S.M.

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Ma, Chengbang. "Functional genomic studies on reptile venom." Thesis, Queen's University Belfast, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.579787.

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Natriuretic peptides are common components of reptile venoms and molecular cloning of their biosynthetic precursors has revealed that in snakes, they eo-encode bradykinin-potentiating peptides and in venomous lizards, some eo-encode bradykinin inhibitory peptides such as the helokinestatins. The common natriuretic peptide/helokinestatin precursor of the Gila Monster, Heloderma suspectum, encodes five helokinestatins of differing primary structures. Here we report the molecular cloning of a natriuretic peptide/helokinestatin precursor cDNA from a venom-derived cDNA library of the Mexican beaded lizard (Heloderma horridum) and the Gila Monster (Heloderma suspectum) and the structures of the novel peptides, helokinestatin-6, helokinestatin-7S and helokinestatin-7H, that have inhibitory effects on bradykinin responses in vascular smooth muscle. Snakes of the Elapidae and Viperidae families have evolved to produce venoms with specific well- defined modes of action that lead to prey immobilisation and ultimately death. The venoms of elapids contain neurotoxic components that attack both the peripheral and central nervous systems. In this project, dendrotoxin-K/I sequences from black mamba (Dendroaspis polylepis) venom were obtained, and these have inhibitory effects on the proteases, trypsin and chymotrypsin. The structures were obtained through use of a special primer in the 'shotgun cloning' of a venom- derived cDNA library. By this approach, the structure and precursor sequence of cardiotoxin-3 from the venom of the King Cobra, (Ophiophagus hannah) was also obtained. In contrast, viperid snake venoms contain components that are mainly haemorrhagic in nature or act upon the vascular system in other ways. Using the same molecular cloning strategy as adopted for elapid snakes, the structure of a novel C-type lectin was obtained from Puff Adder (Bitis arietans) venom and that of a novel PLA2 from the venom of the Cantil (Agkistrodon bilineatus).

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Chen, Tianbao. "Molecular studies on selected amphibian and reptile venom." Thesis, University of Ulster, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398989.

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Foucart, Thomas. "L'évolution de l'oviparité à la viviparité chez les reptiles : approche éco-physiologique de l'équilibre des coûts et bénéfices chez une espèce à reproduction bimodale (Zootoca vivipara)." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S125/document.

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Dans son Historia Animalium en 343 av. J.C., Aristote proposait déjà deux critères qui continuent d’être les bases fondamentales de notre compréhension de la diversité des modes de reproduction : l’origine des nutriments des embryons (lécitotrophie vs. matrotrophie) et le mode de parition (oviparité vs. viviparité). Depuis plusieurs décennies la compréhension de la transition évolutive vers la viviparité a attiré un intérêt scientifique considérable. En effet les analyses phylogénétiques récentes reconnaissent une évolution indépendante de la viviparité dans plus de 150 lignées de vertébrés dont au moins 115 concernent uniquement le taxon des reptiles squamates actuels (lézards, serpents et amphisbènes). Les lignées présentant une transition évolutive de l’oviparité à la viviparité chez les squamates se retrouvent généralement associées aux climats froids, mais pas uniquement. Les explications proposées pour ce patron reposent sur le contrôle comportemental de la température de développement chez les femelles gestantes, offrant ainsi des températures plus favorables que celles des sites de ponte situés sous la surface du sol. Durant cette thèse doctorale nous avons étudié une espèce à reproduction bimodale (Zootoca vivipara) chez qui coexistent des populations ovipares et vivipares disjointes. Ce contexte nous a permis de comparer les modes reproducteurs en minimisant les biais phylogénétiques. Nous avons pu mettre en évidence et quantifier différents coûts « potentiels » de la reproduction (énergétique, contrainte volumique, phénotype des nouveau-nés) et certains bénéfices (phénologie et performance des nouveau-nés) associés à la régulation maternelle du développement. Nos résultats nous amènent à discuter des différentes pressions de sélection s’exerçant sur la durée de rétention des embryons, dont les directions seraient opposées et/ou dont l’intensité serait variable au cours du développement embryonnaire. Dans ce schéma, la viviparité ne devrait être favorisée que dans des contextes plus contraignants et où les bénéfices thermiques compensent les coûts de prolongation de la rétention. Ce contexte sélectif aurait abouti chez les squamates à l’existence de deux modalités reproductives avec entre elles une instabilité évolutive des états intermédiaires
In his Historia Animalium in 343 B.C., Aristotle proposed two fundamental distinguishing criteria for reproductive diversity: the source of nutrients for embryonic development (lecitotrophy vs. matrotrophy) and partuition mode (oviparity vs. viviparity). Understanding the evolutionary transition to viviparity attracted considerable scientific interest over the past few decades. Phylogenetic analyses indicate that viviparity has originated independently in more than 150 vertebrate lineages, including in a minimum of 115 clades of extant squamate reptiles (lizards, snakes and amphisbaenians). Transitions from oviparity to viviparity in squamate reptiles seem closely related to cold climates, but not exclusively. Explanations for this pattern are based on the fact that pregnant females can behaviouraly thermoregulate and thus offer more suitable developmental temperatures than those available in nests under the soil surface. During this PhD thesis we studied a reproductively bi-modal species (Zootoca vivipara) in which non-overlapping oviparous and viviparous populations exist. This context allowed us to compare oviparous and viviparous reproductive modes while minimizing phylogenetic biases. We identified and quantified potential reproductive costs (energy, volume constraints, offspring phenotype) and also benefits (phenology and offspring performances) associated with maternal thermoregulation. Our results provide support for multiple selective pressures on embryo retention, with variable intensities and opposite directions depending on embryonic developmental stage. In this scheme, viviparity should be selected in constraining environments where thermal advantages exceed the costs of increased retention. This context may explain the dichotomy observed in squamate reproductive modes and the evolutionary instability of intermediate stages

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Olsson, Cecilia. "Amphibian and reptile distribution in forests adjacent to watercourses." Thesis, Karlstad University, Faculty of Social and Life Sciences, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-3301.

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Worldwide amphibians and reptiles are declining with habitat fragmentation and destruction as the primary cause. Riparian areas are important for the herpetofauna, but as land is converted to agriculture or harvested for timber the areas are diminishing. The aim of this study was to examine amphibian and reptile abundance in relation to distance from water and in relation to habitat characteristics, foremost per cent deciduous trees. The survey was conducted during spring at six different locations, with continuous forest along streams or rivers, outside of Karlstad, Sweden. Animals were searched along four lines parallel to the water and each study area was visited five times. Statistical analyses were made for grass snake (Natrix natrix), common lizard (Lacerta vivipara) and frogs with joined data of common frog (Rana temporaria) and moor frog (R. arvalis). As expected both reptiles were positively correlated with per cent deciduous trees, with the strongest significance for the common lizard. For grass snake there was also a difference between survey periods, which might reflect the importance of weather. Frogs revealed no trends to trees, but there was a significant difference for habitat characteristics like amount woody debris and per cent bare ground. None of the species were correlated with distance from water which was surprising, especially for the frogs which is more dependent on water than the reptiles. Grass snakes hunt in the water, but the common lizard has no such associations to the water, yet the latter did reveal a slight trend towards being more numerous closer to the water. The causes behind lacking correlation to distance from water may be many, but water characteristics seem very important. Many amphibians prefer warm and calm ponds over running water that in general are colder and likely to inhabit more predators. It was assumed that the amphibians breed in the streams or rivers, but it is possible that other water bodies may have served as breeding sites, which mean the starting point was incorrect.

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Queissada, Ingrid Carolline Soares Tiburcio [UNESP]. "Diversidade da herpetofauna de uma área de Mata Atlântica do estado de Alagoas: a reserva particular da usina Porto Rico, Campo Alegre." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/99537.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
A Mata Atlântica é reconhecida internacionalmente como uma das 25 hotspots do planeta e engloba áreas com elevado endemismo, grande diversidade de espécies e fortes pressões antrópicas. É a segunda floresta mais ameaçada e abriga muitas espécies com risco de extinção. Os anfíbios e répteis constituem a chamada herpetofauna, formando um grupo que se destaca em quase todos os habitats terrestres e também são abundantes e importantes em ambientes aquáticos. No Brasil esse grupo está representado por 841 espécies de anfíbios, e 701 espécies de répteis. A maior diversidade desse grupo de animais ocorre em florestas tropicais úmidas, porém o frequente processo de fragmentação que estas florestas vêm sofrendo pode causar efeitos como a redução e até a extinção de populações. O presente estudo foi realizado na Reserva Particular da Usina Porto Rico e seu entorno, município de Campo Alegre, estado de Alagoas. O trabalho teve como principal objetivo conhecer a composição de espécies da herpetofauna na Reserva e comparar área de borda e área de interior de mata em relação à composição de espécies. Para as análises estatísticas só foram utilizados dados obtidos com o uso das armadilhas de interceptação e queda. Durante o período de junho de 2006 a agosto de 2007 foram registradas 29 espécies de anuros, 17 espécies de lagartos e 19 espécies de serpentes, capturados pelos métodos de busca ativa e de armadilhas de interceptação e queda e através de encontros acidentais. A composição herpetofaunística foi bastante similar quando comparados interior e borda de mata (coeficiente de Jaccard = 0,75862). Uma espécie típica de áreas abertas, Physalaemus cuvieri, foi a mais abundante tanto no interior da mata quanto na borda. Uma espécie considerada rara, Macrogenioglottus alipioi, foi encontrada na área de estudo enfatizando a importância da conservação desse remanescente florestal.
Atlantic Forest is internationally recognized as one of the 25 hotspots on the planet which embodies high endemism and high diversity areas over strong anthropic influence. This forest composing the second mort threatened forest, and representing an unique shelter for many endangered species. Amphibians and reptiles constitute what we named herpetofauna. This group to detach about all terrestrials habitats also is important and abundant in aquatics environments. In Brazil, the herpetofauna represent 841 amphibians species, and, 701 reptiles species. Its diversity occurs mainly within rain forests, but in these forests the frequent fragmentation processes may result on severe effects such as population reduction as extinct species. This study was developed at Usina Porto Rico Particular Reserve, Campo Alegre municipal district, Alagoas State. This aim of this work was to know the herpetofauna species composition in Reserve and to compare edge and interior of the forest. Only used data obtained about pittfall traps to statistical analyzes. From June 2006 to August 2007, 29 amphibians species, 17 lizards species and 19 snakes species were registered about pitfall traps and active look search and about accidental encounter. The herpetofauna composition was similar between edge and interior of the forest (Jaccard coefficient = 0,75862). One specie, Physalaemus cuvieri, typical of the open areas, was the most abundant in the edge as much as interior of the forest. One rare specie Macrogenioglottus alipioi was found within the studied área, pointing out the importance of this Forest remnant conservation.

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Laurencio, David Edelman. "Environmental correlates to amphibian and reptile diversity in Costa Rica." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1675.

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Quinn, Alexander E., and n/a. "EVOLUTION OF SEX-DETERMINING MECHANISMS IN REPTILES." University of Canberra. Institute for Applied Ecology, 2008. http://erl.canberra.edu.au./public/adt-AUC20090311.120346.

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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.

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Van, Wilgen Nicola Jane. "Alien invaders and reptile traders : risk assessment and modelling of trends, vectors and traits influencing introduction and establishment of alien reptiles and amphibians." Thesis, Stellenbosch : Stellenbosch University, 2010. http://hdl.handle.net/10019.1/5468.

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Thesis (PhD)--Stellenbosch University, 2010.
ENGLISH ABSTRACT: Biological invasions are a growing threat to biodiversity, trade and agriculture in South Africa. Though alien reptiles and amphibians (herpetofauna) are not currently a major issue, escalating problems worldwide and increased trade in South Africa suggest a possible increase in future problems. In this thesis I explore practical measures for risk assessment implementable under national legislation. I began by documenting record-keeping and legislative differences between provinces in South Africa. This revealed some serious deficiencies, complicating attempts to compile accurate inventories and discern import trends. International trade data, however, revealed an exponential increase in the number of imports to South Africa over the last 30 years. Characterising the abundance of species in this trade is important as species introduced in large numbers pose a higher establishment risk. In South Africa, I found a tendency for venomous and expensive species to be traded in low numbers, whereas species that are easy to breed and handle, or that are colourful or patterned are traded in higher numbers. Unlike South Africa, California and Florida have had a large number of well-documented herpetofaunal introductions. These introductions were used to verify the role of several key predictors in species establishment. I first evaluated the role of each variable separately. I examined different approaches for bioclimatic modelling, the predictive power of different sources of distribution data, and methods of assigning a climate-match score. I also present the first test of Darwin’s naturalization hypothesis for land vertebrates using two new phylogenies inferred for native and introduced reptiles in California and Florida. I then used boosted regression trees (BRT) to infer the relative contribution of each factor to species establishment success. Results from the BRTs were incorporated into a user-friendly spreadsheet model for use by assessors inexperienced in complex modelling techniques. Introduction effort was found to be the strongest contributor to establishment success. Furthermore, species with short juvenile periods were more likely to establish than species that started breeding later, as were species with more distant relatives in regional biotas. Average climate match and life form were also important. Of the herpetofaunal groups, frogs and lizards were most likely to establish, while snakes and turtles established at much lower rates, though analysis of all recorded herpetofaunal introductions shows slightly different patterns. Predictions made by the BRT model to independent data were relatively poor, though this is unlikely to be unique to this study and can be partially explained by missing data. Though numerous uncertainties remain in this field, many can be lessened by applying case by case rules rather than generalising across all herpetofaunal groups. The purpose for import and potential trade volume of a species will influence the threat it poses. Considering this in conjunction with a species’ environmental tolerances and previous success of species with similar life histories, should provide a reasonable and defendable estimate of establishment risk. Finally, a brief summary of the potential impacts of introduced alien herpetofauna is provided in the thesis.
AFRIKAANSE OPSOMMING: Indringer spesies hou ‘n al groter bedreiging in vir die biodiversiteit, handel en landbou van Suid- Afrika. Alhoewel uitheemse reptiele en amfibieërs (herpetofauna) tans nie ‘n groot bedreiging in Suid-Afrika is nie, dui groeiende probleme wêreldwyd asook 'n toename in plaaslike handel op moontlike toekomstige probleme. In hierdie tesis, ondersoek ek praktiese metodes vir risikobepaling wat onder nasionale wetgewing toegepas kan word. Ek begin deur die verskille in stoor van rekords en wetgewing tussen provinsies te dokumenteer. Hierdie proses het ernstige tekortkominge uitgewys, wat pogings om akkurate inventarisse saam te stel en invoertendense te bepaal, bemoeilik. Internasionale handelsdata het egter getoon dat daar ‘n eksponensiële toename in die hoeveelheid invoere na Suid-Afrika oor die laaste 30 jaar was. Die hoeveelheid spesies in hierdie handel is belangrik omdat spesies wat in groot hoeveelhede ingevoer word, ‘n hoër vestigingsrisiko het. In Suid-Afrika is ‘n tendens gevind vir handel in giftige en duur spesies teen lae hoeveelhede, terwyl spesies wat maklik teel, maklik hanteer kan word en kleurvol is of mooi patrone het, in groter hoeveelhede mee handel gedryf word. Kalifornië and Florida, in teenstelling met Suid-Afrika, het ‘n hoë aantal goed-gedokumenteerde gevalle van herpetofauna wat in die natuur vrygestel is. Hierdie introduksies was gebruik om die rol van verskeie belangrike faktore in die vestiging van populasies te bepaal. Eerstens het ek die rol van elke faktor apart ondersoek. Ek het verskillende benaderinge vir bioklimatiese model-bou ondersoek, die akuraatheid van verskillende bronne van distribusiedata getoets en drie metodes om ‘n “climate match score” te bereken, voorgestel. Ek bied ook die eerste toets van Darwin se naturalisasie-hipotese vir landwerveldiere aan, deur gebruik te maak van twee nuwe filogenieë wat ek gebou het vir inheemse en ingevoerde reptiele in Kalifornië en Florida. Ek het verder gebruik gemaak van “boosted regression trees” (BRT) om die relatiewe bydrae van elke faktor tot die vestigings-potensiaal van spesies te bepaal. Resultate van hierdie BRTs was ingekorporeerd in ‘n gebruikersvriendelike ontledingstaat wat deur bestuurders, onervare in komplekse modelboutegnieke, gebruik kan word. Invoer-hoeveelheid was die faktor wat die sterktste bygedra het tot suksesvolle vestiging. Verder is spesies met kort jeugperiodes en dié met verlangse familie in streeks-biotas, meer geskik om suksesvol te vestig. Gemiddelde klimaatooreenstemming en lewensvorm was ook belangrik. Paddas en akkedisse was die mees waarskynlikste van die herpetofauna groepe om populasies te vestig, terwyl slange en skilpaaie teen laer tempo’s populasies gevestig het, alhoewel analise van alle gedokumenteerde gevalle van herpetofauna-invoerings wêreldwyd effens verskillende tendense toon. Voorspellings wat deur die BRT-model vir onafhangklike data gemaak is was redelik swak, alhoewel hierdie resultaat onwaarskynlik nie uniek aan die studie is nie, en word gedeeltelik verduidelik deur die gebrek aan data. Alhoewel talle onsekerhede steeds bestaan, kan dié verminder word deur geval-tot-geval reëls toe te pas eerder as om vir herpetofauna as ‘n groep te veralgemeen. Die doel van invoer en potensiële handel-volumes van ‘n spesie, sal die bedreiging wat die spesie toon, bepaal. Hierdie faktore moet saam met omgewingstoleransie en voorafgaande sukses van spesies met soortgelyke lewenswyses oorweeg word, om ‘n aanvaarbare en verdedigbare beraming van vestigingsrisiko te gee. Laastens, word ‘n kort opsomming van die effekte wat uitheemse herpetofauna mag hê, verskaf.

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Barends, Jody Michael. "Predicting reptile species distributions and biogeographic patterns within Kruger National Park." University of the Western Cape, 2018. http://hdl.handle.net/11394/6745.

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Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol)
Knowledge of global reptile ecology is limited and there remains much to understand in terms of detailed reptile species information, including that of their distributions. In South Africa, despite being one of SANParks best-studied reserves, surprisingly little is known about the distributions and spatial ecology of reptiles within Kruger National Park (KNP). Management within KNP follows a strategic adaptive management strategy which monitors the statuses of animals using species or group specific indicators. Indicators are given predetermined upper and lower ranges of acceptable fluctuation before actions are taken. These ranges are referred to as thresholds of potential concern (TPCs), and for reptiles these are based on changes to their distributions across the landscape of KNP. An apparent lack of high-quality reptile distribution data inhibits the effective monitoring of the statuses of these animals within KNP, which in turn limits management and conservation options. In this study, I use several methods to quantify available reptile occurrence data which formed the foundations for predicting the distributions of these species across KNP by means of species distribution modelling, with a view to gaining novel insight into reptile assemblage structure across the landscape of KNP.

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Thompson, Michelle E. "Recovery of Amphibian and Reptile Communities During Tropical Secondary Forest Succession." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3701.

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The extensive clearing and modification of natural systems from anthropogenic activities is a pressing global concern. Forest habitats and animal communities within forests are among the most highly impacted, globally. Forest destruction has been repeatedly documented as a driver of biodiversity loss. However, little is known about how animal communities respond when altered landscapes are abandoned and left to regenerate into secondary forests. It is thought that the regrowth of secondary forests may help reverse biodiversity loss by restoring habitats to similar conditions as prior to land conversion. Of the forest cover that remains, over half is secondary forest, and in many countries secondary forest cover has been steadily increasing. Therefore, it is important to understand how and if faunal communities recover during secondary forest regeneration. I combined meta-analytic, field-survey-based, and lab-based experimental techniques to determine how amphibians and reptiles respond to habitat change in general, and secondary forest regeneration on landscapes previously cleared for use as pasture. I addressed five specific questions: 1) what are the effects of habitat alteration on amphibians and reptiles?, 2) what are the effects of secondary forest succession on amphibians and reptiles?, 3) what is the relative importance of stochastic and deterministic effects on community assembly during secondary forest succession?, 4) how do amphibian and reptile species composition, probability of occurrence, and species richness change over the course of secondary forest succession?, and 5) is thermal quality of habitat an important mechanism of species response to secondary forest succession? I found that secondary forest has high conservation value for many amphibian and reptile species, environmental changes associated with secondary forest succession have a significant effect on shaping amphibian and reptile community composition, thermal quality is an important mechanism for species response and that strength of response is mediated by species-specific thermal biology. I also highlight the importance of riparian corridors in maintaining species diversity in modified habitats.

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Queissada, Ingrid Carolline Soares Tiburcio. "Diversidade da herpetofauna de uma área de Mata Atlântica do estado de Alagoas : a reserva particular da usina Porto Rico, Campo Alegre /." Rio Claro : [s.n.], 2009. http://hdl.handle.net/11449/99537.

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Orientador: Hussam El Dine Zaher
Banca: Gabriel Omar Skuk Sugliano
Banca: Otavio Augusto Vuolo Marques
Resumo: A Mata Atlântica é reconhecida internacionalmente como uma das 25 hotspots do planeta e engloba áreas com elevado endemismo, grande diversidade de espécies e fortes pressões antrópicas. É a segunda floresta mais ameaçada e abriga muitas espécies com risco de extinção. Os anfíbios e répteis constituem a chamada herpetofauna, formando um grupo que se destaca em quase todos os habitats terrestres e também são abundantes e importantes em ambientes aquáticos. No Brasil esse grupo está representado por 841 espécies de anfíbios, e 701 espécies de répteis. A maior diversidade desse grupo de animais ocorre em florestas tropicais úmidas, porém o frequente processo de fragmentação que estas florestas vêm sofrendo pode causar efeitos como a redução e até a extinção de populações. O presente estudo foi realizado na Reserva Particular da Usina Porto Rico e seu entorno, município de Campo Alegre, estado de Alagoas. O trabalho teve como principal objetivo conhecer a composição de espécies da herpetofauna na Reserva e comparar área de borda e área de interior de mata em relação à composição de espécies. Para as análises estatísticas só foram utilizados dados obtidos com o uso das armadilhas de interceptação e queda. Durante o período de junho de 2006 a agosto de 2007 foram registradas 29 espécies de anuros, 17 espécies de lagartos e 19 espécies de serpentes, capturados pelos métodos de busca ativa e de armadilhas de interceptação e queda e através de encontros acidentais. A composição herpetofaunística foi bastante similar quando comparados interior e borda de mata (coeficiente de Jaccard = 0,75862). Uma espécie típica de áreas abertas, Physalaemus cuvieri, foi a mais abundante tanto no interior da mata quanto na borda. Uma espécie considerada rara, Macrogenioglottus alipioi, foi encontrada na área de estudo enfatizando a importância da conservação desse remanescente florestal.
Abstract: Atlantic Forest is internationally recognized as one of the 25 hotspots on the planet which embodies high endemism and high diversity areas over strong anthropic influence. This forest composing the second mort threatened forest, and representing an unique shelter for many endangered species. Amphibians and reptiles constitute what we named herpetofauna. This group to detach about all terrestrials habitats also is important and abundant in aquatics environments. In Brazil, the herpetofauna represent 841 amphibians species, and, 701 reptiles species. Its diversity occurs mainly within rain forests, but in these forests the frequent fragmentation processes may result on severe effects such as population reduction as extinct species. This study was developed at Usina Porto Rico Particular Reserve, Campo Alegre municipal district, Alagoas State. This aim of this work was to know the herpetofauna species composition in Reserve and to compare edge and interior of the forest. Only used data obtained about pittfall traps to statistical analyzes. From June 2006 to August 2007, 29 amphibians species, 17 lizards species and 19 snakes species were registered about pitfall traps and active look search and about accidental encounter. The herpetofauna composition was similar between edge and interior of the forest (Jaccard coefficient = 0,75862). One specie, Physalaemus cuvieri, typical of the open areas, was the most abundant in the edge as much as interior of the forest. One rare specie Macrogenioglottus alipioi was found within the studied área, pointing out the importance of this Forest remnant conservation.
Mestre

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Zuël, Nicolas. "Ecology and conservation of an endangered reptile community on Round Island, Mauritius /." [S.l.] : [s.n.], 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000292620.

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Meyer, Anita. "The relevance of the Greater Cederberg Biodiversity Corridor (GCBC) for reptile conservation." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/21676.

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Thesis (MSc)--Stellenbosch University, 2008.
ENGLISH ABSTRACT: The Greater Cederberg Biodiversity Corridor (GCBC) is a large-scale conservation corridor situated in the south-western region of South Africa. Delineation of the GCBC was largely based on by vegetation data. The relevance of the GCBC for the conservation of the reptilian fauna in the area south of 31°S and west of 21°E is assessed in the present study. This entailed determining the GCBC’s coverage of regional reptile diversity patterns and assessing its potential conservation significance during possible climate induced changes in reptile distributions. Reptile species point distribution data from the preliminary (2007) SARCA (South African Reptile Conservation Assessment) database was used. Under-representation of the Tankwa Karoo in the dataset required a field survey of this region. Additionally, the biogeographical influence of the arid Tankwa Karoo Basin on the distribution of reptiles in the south-western districts of South Africa was investigated. Turnover across the Basin is high, species richness is lower than in surrounding mountainous areas and there are no species endemic to the area. The Tankwa Karoo Basin acts as a dispersal barrier for many reptile species occurring in the surrounding more mesic areas. At the same time, the ranges of a number of typical northern, arid adapted species extend southward along the Tankwa Plains. A number of species range extensions in the region are reported. Patterns of endemism, species richness and turnover were plotted from the point distribution data at quarter and eighth degree square resolution. Extensive sampling bias towards reserves and populated areas is apparent from the reptile species richness plots. This pattern is more pronounced for snakes than lizards. Reptile richness is particularly high along the north-south section of the Cape Fold Mountains and also relatively high along the south-western coast, peaking in the Lambert’s Bay area. The majority of the 20 reptile species endemic to the study area are associated with one of two identified centres of endemism: the Greater Cederberg area, or the narrow coastal zone stretching from the Lambert’s Bay area to the Cape Peninsula. An additional third set of endemics comprised of melanistic forms restricted to a number of different refugia, notably, Landroskop, the Cape Peninsula, Sladanha-Langebaan region, Piketberg Mountains and a confined area along the western section of the Cape Fold Mountains. Species richness and endemism patterns co-vary within the study area. Biotic regions were identified through hierarchical clustering of grid cells according to shared species occurrences. A Northern, Southern, Central and Western biotic region was identified. Classification tree methodology (CART) and Canonical Correspondence Analysis (CCA) were used to characterise defined biotic regions in terms of selected environmental variables. Four sets of species assemblages are described on the basis of these biotic regions – two major and two minor ones. Of the major assemblages the Northern assemblage can be described as an arid zone one and the Southern assemblage as a mesic zone one. The minor Central assemblage, comprising mainly rock-dwelling forms, represent evolutionary leftovers as a result of climate change induces cycles of contraction and expansion of arid and mesic faunas. The other minor one, the West Coast assemblage could be considered a sub-assemblage of the Northern one, with particular adaptation to the coastal climate. Environmental characterisation of the biotic regions reveals that these groupings are supported by an environmental signal. The contiguity of four distinct sets of reptiles, each with its own set of environmental requirements, in this relatively small geographic area clearly indicates that the southwestern region of South Africa is biogeographically complex. The GCBC incorporates the largely coinciding centres of endemism and richness along the West Coast and the greater Cederberg area. Although the centre of endemism for melanistic reptile forms, in the Saldanha-Langebaan area, falls just south of the GCBC boundary, the Corridor fulfils the requirements for effective conservation of reptiles in the area to a large degree. The north-south dispersal pathways provided by the Corridor along the Cape Fold Mountains is believed to be adequate to buffer climate change effects, however there is concern about its ability to contribute to the persistence of the assemblage associated with the narrow coastal zone in the west.
AFRIKAANSE OPSOMMING: Die Groter Cederberg Biodiversiteit Korridor (GCBK) is ‘n grootskaalse bewaringskorridor wat in die suid-westelike deel van Suid-Afrika geleë is. Die grense van GCBK is gebasseer op plantegroei data. In die huidige studie word die betekenis van die GCBK vir die bewaring van die reptiel fauna in die gebied suid van 31°S en wes van 21°O assesseer. Die mate waartoe die GCBK die patrone van reptieldiversiteit in die streek inkorporeer, asook die korridor se potensiaal om voorsiening te maak vir reptiel verspreidingsgebiede wat moontlik as gevolg van potensiële omgewingsverandering kan verskuif. Die beskikbare puntverspreidingsdata van die voorlopige (2007) SARCA (South African Reptile Conservation Assessment) databasis is gebruik. Swak verteenwoordiging van die Tankwa Karoo in die datastel het ‘n veldopname van die gebied genoodsaak. Verder is die biogeografiese invloed van die ariede Tankwa Karoo Kom op die verspreidingspatrone van reptiele in die suid-westelike deel van Suid-Afrika ook ondersoek. Die spesie omset van beide Noord na Suid en Wes na Oos oor die Tankwa is hoog, die spesierykheid is aansienlik laer as in die omringende bergagtige gebiede en daar is geen spesies wat endemies is tot die Tankwa Karoo nie. Die Tankwa Karoo Kom dien as ‘n barieêre teen spreiding vir sommige reptielspesies wat in die omringende gematigde gebiede voorkom. Terselfdertyd reik die verspreidings van ‘n aantal tipiese droogte aangepasde spesies vanuit die noorde suidwaarts langs die Tankwa Vlaktes. Nuwe verspredingsrekords wat ‘n paar spesies se gebiede uitbrei word ook raporteer. Die puntverspreidingsdata is geruik om die patrone van endemisme, spesierykheid en omset op kwart- en agtstegraad resolusie te plot. Spesierykheid kaarte toon ‘n duidelike neiging tot deegliker opnames in reservate en bewoonde gebiede. Hierdie patroon is meer opmerklik vir slange as akkedisse. Reptielrykheid is besonders hoog langs die noord-suid as van die Kaapse Plooiberge en ook relatief hoog langs die suid-wes kus met ‘n maksimum in die Lambertsbaai omgewing. Die meerderheid van die 20 reptielspesies wat endemies is aan die studie area is met een van twee geïdentifiseerde sentrums van endemisme geassosieer: die Groter Cederberg area óf die nou kussone wat vanaf Lambertsbaai tot Kaappunt strek. ‘n Derde stel endemiese spesies wat uit melanistiese vorme bestaan, is beperk tot ‘n aantal refugia, naamlik, Landroskop, Kaappunt, Saldanha- Langebaan omgewing, Piketberg berge en ‘n beperkte area langs die westelike dele van die Kaapse Plooiberge. Spesierykheid en endemisme patrone stem grootliks ooreen binne die studie area. Roosterselle is op grond van gedeelde spesiesamestellings met behulp van ‘n hieragiese groeperingsmetode (Incremental Sum of Squares) gegroepeer. Vier bio-areas, nl. ‘n Noordelike-, Suidelike-, Sentrale en Westelike bio-area is identifiseer. Klassifikasieboom metodologie (Classification and Regression Trees, CART) asook Kanoniese Annalises (Cannonical Correspondence Annalysis, CCA) is gebruik om hierdie geografiese areas in terme van ‘n aantal omgewingsveranderlikes te karakteriseer. Vier spesieversamelings, twee groter en twee kleiner versamelings, is in ooreenstemming met hierdie vier areas geïdentifiseer. Die Noordelike en Suidelike spesieversamelings is die groteres en kan beskryf word as die faunas van onderskeidelik ‘n ariede en gematigde sone. Die kleiner Sentrale versameling bestaan hoofsaaklik uit rots-lewende spesies en mag die evolusionêre oorblyfsels verteenwoordig van ariede en gematigde faunas waarvan die verspreidings herhaaldelik as gevolg van klimaatsveranderingsiklusse uitgebrei en gekrimp het. Die Weskus versameling is ook ‘n kleiner een en kan as ‘n sub-versameling van die Noordelike een beskou word, maar spesifiek tot die kus klimaat aangepas. Die klassifikasie van hierdie bio-areas word ondersteun deur die analiese van die omgewingsveranderlikes. Die feit dat vier kenmerkende versamelings reptiele, elk met sy besondere omgewingsvereistes, in hierdie relatief klein geografiese area ontmoet, dui daarop dat die suid-westelike deel van Suid-Afrika biogeografies kompleks is. Die GCBK inkorporeer die grootliks ooreenstemmende sentrums van endemisme en rykheid wat langs die Weskus en in die groter Cederberg area voorkom. Alhoewel die sentrum van melanistiese endemiese spesies, in die Saldanha-Langebaan omgewing, net buite die grense van die Korridor val, voldoen die GCBK grootliks aan die vereistes vir die effektiewe bewaring van reptiele in die gebied. Die voorsiening van noord-suid verspreidingsweë langs die Kaapse Plooiberge binne die Korridor word beskou as voldoende om die gevolge van klimaatsverandering te buffer. Daarinteen is daar kommer oor die vermoeë van die GCKB om ‘n doeltreffende bydrae te maak tot die voortbestaan van die spesieversameling wat met die nou kussone langs die Weskus geassosieer is.

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Thompson, Scott A. "Mine site rehabilitation index using the reptile assemblage as a bio-indicator." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2004. https://ro.ecu.edu.au/theses/1646.

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Currently in Western Australia there are no mandated standards for assessing rehabilitation success for the mining industry. A decade ago the focus of most mine site rehabilitation programs was to establish good density and cover of vegetation across the disturbed area. While this resulted in rehabilitated sites that were essentially stable and may have looked aesthetically pleasing, it did not necessarily mean that the rehabilitated sites were moving towards the establishment of functional ecosystems. The goal for rehabilitated mined land should be to restore the structure, diversity, function and dynamics, of the undisturbed ecosystem. In many circumstances this will mean the creation of a self-sustaining, functional ecosystem similar to that in the adjacent undisturbed area from which the rehabilitated area will recruit most of its fauna. The need for 'high-quality' rehabilitation has become necessary with the phasing in of performance standards for assessing the development of rehabilitated mine sites. Mine site rehabilitation should be viewed as managing succession processes towards the creation of ecosystems that are functionally compatible with that which existed before the disturbance or in the adjacent undisturbed areas.

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Tejero, Cicuéndez Héctor 1993. "Patterns and drivers of desert reptile diversity at different phylogenetic and spatial scales." Doctoral thesis, TDX (Tesis Doctorals en Xarxa), 2021. http://hdl.handle.net/10803/672957.

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Biodiversity patterns result from the interplay of evolutionary, ecological, and environmental processes. Investigating the drivers of such patterns is central to evolutionary biology, and it is further essential to understand how the undergoing global changes will shape the future of biodiversity. This thesis explores diversity patterns and their drivers at different taxonomic and spatial scales, using reptiles from arid regions as a model of study. Specifically, this thesis analyzes the ecomorphological diversity of the Afro-Arabian geckos of the genus Pristurus in the context of island colonization and habitat specialization, the biogeographic patterns of Afro-Arabian squamates in the light of the region's geologic and climatic history, and the differences in lizard richness among the greatest deserts of the world. General processes were identified as determinant for the evolution of arid reptiles, although the results also highlight the complexity and the system-specific nature of biodiversity patterns and their drivers
Los patrones de biodiversidad son el resultado de múltiples procesos evolutivos, ecológicos y ambientales. Estudiar las causas de dichos patrones es fundamental en biología evolutiva, y además es clave para entender el impacto de los presentes cambios globales en la biodiversidad. Esta tesis utiliza los reptiles de las zonas áridas para explorar patrones de diversidad y sus causas a distintas escalas taxonómicas y geográficas. Concretamente, se analizan la diversidad ecomorfológica de los geckos Pristurus en el contexto de la colonización de islas y la especialización de hábitat, los patrones biogeográficos de los reptiles de Afro-Arabia a la luz de la historia geológica y climática de la región, y las diferencias en diversidad de lagartos entre los grandes desiertos del mundo. Se identificaron procesos clave en la evolución de los reptiles de zonas áridas, pero los resultados también demuestran la complejidad de los patrones de diversidad y sus causas.

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Fath, Natalie A. "AMPHIBIAN AND REPTILE SPECIES SURVEY AND HABITAT ASSESSMENT: INCORPORATING ENVIRONMENTAL EDUCATION AND OUTREACH." Miami University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=miami1208884596.

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Thompson, Danielle Kaye. "Amphibian and Reptile Species Survey and Habitat Assessment: Incorporating Environmental Education and Outreach." Miami University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=miami1208912407.

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Van, Doorslaer Koenraad, Valeria Ruoppolo, Annie Schmidt, Amelie Lescroël, Dennis Jongsomjit, Megan Elrod, Simona Kraberger, et al. "Unique genome organization of non-mammalian papillomaviruses provides insights into the evolution of viral early proteins." OXFORD UNIV PRESS, 2017. http://hdl.handle.net/10150/627073.

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The family Papillomaviridae contains more than 320 papillomavirus types, with most having been identified as infecting skin and mucosal epithelium in mammalian hosts. To date, only nine non-mammalian papillomaviruses have been described from birds (n = 5), a fish (n = 1), a snake (n = 1), and turtles (n = 2). The identification of papillomaviruses in sauropsids and a sparid fish suggests that early ancestors of papillomaviruses were already infecting the earliest Euteleostomi. The Euteleostomi clade includes more than 90 per cent of the living vertebrate species, and progeny virus could have been passed on to all members of this clade, inhabiting virtually every habitat on the planet. As part of this study, we isolated a novel papillomavirus from a 16-year-old female Adelie penguin (Pygoscelis adeliae) from Cape Crozier, Ross Island (Antarctica). The new papillomavirus shares similar to 64 per cent genome-wide identity to a previously described Adelie penguin papillomavirus. Phylogenetic analyses show that the non-mammalian viruses (expect the python, Morelia spilota, associated papillomavirus) cluster near the base of the papillomavirus evolutionary tree. A papillomavirus isolated from an avian host (Northern fulmar; Fulmarus glacialis), like the two turtle papillomaviruses, lacks a putative E9 protein that is found in all other avian papillomaviruses. Furthermore, the Northern fulmar papillomavirus has an E7 more similar to the mammalian viruses than the other avian papillomaviruses. Typical E6 proteins of mammalian papillomaviruses have two Zinc finger motifs, whereas the sauropsid papillomaviruses only have one such motif. Furthermore, this motif is absent in the fish papillomavirus. Thus, it is highly likely that the most recent common ancestor of the mammalian and sauropsid papillomaviruses had a single motif E6. It appears that a motif duplication resulted in mammalian papillomaviruses having a double Zinc finger motif in E6. We estimated the divergence time between Northern fulmar-associated papillomavirus and the other Sauropsid papillomaviruses be to around 250 million years ago, during the Paleozoic-Mesozoic transition and our analysis dates the root of the papillomavirus tree between 400 and 600 million years ago. Our analysis shows evidence for niche adaptation and that these non-mammalian viruses have highly divergent E6 and E7 proteins, providing insights into the evolution of the early viral (onco-)proteins.

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Halstead, Neal Thomas. "Long-term effects of prescribed fire on reptile and amphibian communities in Florida sandhill." [Tampa, Fla] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0001935.

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23

Foffa, Davide. "Ecology and evolution of the marine reptile faunas of the Jurassic sub-boreal seaway." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33217.

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Jurassic marine ecosystems (ca. 201-145 million years ago) were dominated by three different lineages of reptiles - plesiosaurians, ichthyosaurs and thalattosuchian crocodylomorphs. Stratigraphic and fossil evidence indicates that these animals, like their modern counterparts, were able to coexist in the same environment for over ~50 million years from the Early Jurassic (~180 million years ago) to the Early Cretaceous (~130 million years ago). Marine reptile ecosystems were often very diverse, and included animals from different lineages, of disparate body-size and inferred ecology living alongside each other in the same environment. This unusual diversity suggests that marine reptiles formed complex ecosystems, and may have occupied analogous ecological roles today held by large fish, sharks, crocodiles, sirenians, and cetaceans. However, these comparisons are essentially qualitative, as they are based on the recurring convergent morphologies of skulls, mandibles and dentitions in aquatic tetrapods. Yet, they have never been quantitatively tested. Furthermore, although we have a comprehensive understanding of the anatomy, systematics, phylogenetic relationships, physiology and feeding ecology of these extinct animals, little is still known about the structure and evolution of their ecosystems. Thus, we do not understand what enabled marine reptiles to form complex assemblages, how their fauna changed through time, and more importantly how climatic and environmental changes shaped their long-term evolution. Answering these questions is essential because understanding past marine ecosystems may inform on whether and how modern ones can adjust to changes in the ocean temperature, chemistry and sea-level. In order to establish the reliability of these comparisons, in this project, I consider the evolution of the diverse marine reptile fossil assemblage of the Jurassic Sub-Boreal Seaway (JSBS) of the UK. The fossil record of the JSBS is an ideal case-study for many reasons. Firstly, it is a well-documented, high-diversity ecosystem, represented by hundreds of well-preserved specimens collected from the world-famous Oxford Clay Formations (OCF Callovian-early Oxfordian, late Middle to early Late Jurassic) and Kimmeridge Clay Formation (KCF - Kimmeridgian to Tithonian, Late Jurassic). These specimens have been intensively collected since the XIX century, and are available in museum collections. Secondly, the fossil record of the JSBS covers a continuous interval of ~18 million years (middle Callovian-early Tithonian ~166-148 million years ago) of marine reptile evolution, in a single seaway, during a time of well-documented environmental changes. These changes in sea-level, temperature and chemistry happened in concert with drastic changes in the composition between the OCF and KCF marine reptile faunas across the Middle-Late Jurassic boundary. Unfortunately, to date, the attempts to understand whether there is a correlation between these events have been hampered by the scarcity of fossils material from the intermediate layers of the Oxfordian 'Corallian Gap'. After a brief introduction (Chapter I), this project articulates in two parts. In the first descriptive section (Chapters II, III and IV), I set the bases for the second part by reviewing the fossil record of ichthyosaurs, plesiosaur and thalattosuchians of the JSBS. Particular emphasis was put on the systematics of thalattosuchian crocodylomorphs, and the fossil assemblage of the 'Corallian Gap'. The second part of this thesis is an analytical section (Chapters V and VI), in which, using a suite of numerical techniques, I investigate the ecology, evolution and feeding ecology of marine reptiles through time. A summary of the main conclusions and future directions are presented in Chapter VII. Chapter II is a description of a new genus and species, Ieldraan melkshamensis, a metriorhynchid thalattosuchian from the Callovian of England. The stratigraphic occurrence of this new taxon demonstrates that all the macrophagous lineages of Late Jurassic metriorhynchids originated in the Middle Jurassic, earlier than previously supposed. This also has important implications for the evolution of macropredatory features (particularly the dentition) in this group. In Chapters III and IV, I review the scarce fossil record of the Oxfordian 'Corallian Gap', the least studied stage of the considered ~18 million-year interval. The results show that despite the scarcity and poor preservation of materials compared to the underlying and overlying fossil-rich OCF and KCF, a large variety of marine reptiles lived in the JSBS during the 'Corallian Gap' (middle-late Oxfordian). The study confirms a drop in marine reptile diversity in the Oxfordian, exemplified by the demise of several OCF taxa, but partially counterbalanced by the contemporaneous radiation of some KCF lineages. This review confirms that a faunal turnover severely affected the composition of the JSBS across the Middle-Late Jurassic boundary, and I hypothesise that these faunal changes may have been driven by environmental perturbations during the Oxfordian. In Chapter V, I use the most common marine reptile fossils - teeth - and the revised stratigraphic occurrences of the JSBS (from the previous Chapters), to investigate the evolution of marine reptile groups, through time. Using a multivariate approach I established a quantitative system to assign species to dietary guilds based on dentition features that together with the availability of teeth, allowed examination of diversity and disparity patterns at unprecedented time, and systematic resolutions. The results show that different taxonomic/dietary groups did not overlap, suggesting partitioning of resources based on diet/feeding strategy. The analyses show a decline of shallow-water specialists, the diversification of macrophagous species, deep-diving taxa, and increasing body-size in concert with a deepening of sea-level across the Middle-Late Jurassic boundary. These trends are not accompanied by drops in disparity, but by a selective decline/increase of specific ecological guilds, that mimic the transition from shallow/nearshore to deeper/offshore habitats in modern cetacean coastal assemblages. In Chapter VI, I use a variety of multivariate techniques to present a quantitative assessment of the feeding behaviour of marine reptiles. The aim of this study is investigating the morphological and functional variation of ichthyosaur, plesiosaur and thalattosuchian lower jaws. This is done using a variety of multivariate techniques, and a biomechanical comparative approach. The analyses confirm previous qualitative observations that the ecosystems in the OCF and KCF were markedly distinct in faunal composition and structure. Phylogenetically closely related taxa preferentially cluster together, with minimal overlaps amongst groups in the morphospace. Focus examinations of key morphofunctional complexes reveals that marine reptile subclades are characterised by different combinations that are consistent with their inferred feeding ecologies (based on tooth morphology). Overall, the present quantitative results validate previous qualitative hypothetical feeding ecologies, and reveal multiple instances of morphofunctional convergent evolution. Overall my results also show that, like in modern ocean ecosystems, complex mechanisms of niche and habitat partitioning may have facilitated the coexistence of diverse marine reptile assemblages over tens of millions of years of evolutionary time.

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Eckhardt, Falk [Verfasser]. "A short story: senescence in an annual reptile, Labord’s chameleon (Furcifer labordi) / Falk Eckhardt." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://d-nb.info/1223171655/34.

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D'Cruze, Neil. "Conserving amphibian and reptile diversity in north Madagascar : contributions from baseline herpetological survey work." Thesis, Oxford Brookes University, 2011. http://radar.brookes.ac.uk/radar/items/9ec5ad4d-f0ec-31e4-c23d-ce4e60a3aa89/1.

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Madagascar has long been recognized as one of the world’s priority global hotspots for biodiversity conservation. Its herpetofauna, in particular, is extremely species-rich and diverse with high levels of endemism. By far the most important threat to its continued survival is the relentless destruction of its primary habitats. Socioeconomic factors in combination with particular aspects of Malagasy culture have led to the exploitation of natural resources which have already had an impact at a national level. Conservation strategies are in place to protect this unique fauna. However, in practice they are constrained in part by a lack of information regarding the distribution, abundance, natural history, and habitat requirements of threatened species. Accessible information, generated by baseline herpetological surveys, is particularly lacking for several key regions such as the northern province of Antsiranana. The first study in this research programme represents a review of modern herpetological survey work (1994-2007) in Madagascar and serves to highlight why Antsiranana was selected as a region of focus. The following three studies are focused on baseline herpetological survey work that was conducted in several key sites of conservation importance throughout the province. A further three studies provide an account of six species (previously unknown to science) that were discovered and described as a result of this survey work. The remaining two studies provide an insight into the impact that anthropogenic habitat alteration is having on lizard abundance, diversity and community composition in the extreme north of this island. Overall, these studies represent an advancement of the knowledge regarding a threatened herpetofauna. They elucidate a number of issues pertaining to broader questions of conservation biology in Madagascar that have been traditionally confounded by a lack of evidence.

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Simmons, Donna. "The impact of Phytophthora cinnamomi on reptile communities in banksia woodlands of Western Australia." Thesis, Simmons, Donna (2011) The impact of Phytophthora cinnamomi on reptile communities in banksia woodlands of Western Australia. Honours thesis, Murdoch University, 2011. https://researchrepository.murdoch.edu.au/id/eprint/32587/.

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Pollock, Nicholas B. "FACTORS INFLUENCING ECTOPARASITISM ON WESTERN FENCE LIZARDS (SCELOPORUS OCCIDENTALIS): HOST SEX, TESTOSTERONE, REPRODUCTIVE CONDITION, AND BEHAVIOR." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/548.

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Host-parasite relationships are one of the most common symbiotic relationships present in a diverse array of ecosystems. There are numerous factors that impact the dynamics of these relationships. Major factors that can influence the degree of parasitism include host sex, hormonal state, reproductive condition, and behavior. It has been observed in several vertebrate taxa that males have higher ectoparasite intensities than females and males with increased testosterone have increased ectoparasite intensities. One potential reason for these observations is that testosterone concentrations are elevated in males, particularly during the breeding season, and when circulating concentrations increase males become more vulnerable to ectoparasitism. Here I first tested the hypothesis that higher circulating testosterone concentrations in male western fence lizards (Sceloporus occidentalis) induce higher tick intensities. To examine this hypothesis I implanted male lizards with either testosterone or blank implants in the field. The testosterone-implanted males had significantly higher tick intensities compared to the control males. However, in contrast, control males had significantly higher mite intensities compared to testosterone-implanted males. These results are consistent with other studies suggesting that testosterone impacts certain aspects of host-parasite relationships. However, the exact mechanism for how testosterone influences parasite intensities remains unclear. There are two major current hypotheses for how testosterone influences ectoparasite intensities on males, the first involving immunosuppression and the second involving behavioral patterns and movement. However, another potential reason for why male lizards, particularly those with high circulating testosterone, have higher ectoparasite intensities than female and low testosterone male lizards is that the parasites preferentially choose their host. Furthermore, it has been demonstrated that vitellogenic female lizards have diminished immune function and this could potentially lead to increased ectoparasitism in much the same way that testosterone does in male lizards. Therefore, it is possible that a host preference is also present with vitellogenic versus non-vitellogenic female lizards. Although there have been a few interspecific studies done on this topic there have been no such studies on parasite host preference in reptiles to date. Here I tested three hypotheses: 1. Ticks prefer male lizards to female lizards. 2. Ticks prefer male lizards with high testosterone concentrations to male lizards with normal testosterone concentrations. 3. Ticks prefer vitellogenic female lizards to non-vitellogenic female lizards. All three experiments demonstrated no preference of host by ticks, which suggests they will attach to any suitable host they come across. However, during the male versus female host choice experiment ticks fed faster on vitellogenic female lizards than male lizards and non-vitellogenic female lizards. These results, taken together with previous studies showing higher tick intensities on male lizards, lizards with experimentally elevated testosterone, and reproductive female lizards, provide evidence that ticks do not preferentially choose their host, but instead are found in higher numbers on certain hosts due to some other reason. Other potential explanations include differences in immune function, microhabitat use, and behavioral patterns. One of the major hypotheses as to why male lizards, particularly those with high testosterone concentrations, have higher ectoparasite intensities than female lizards and male lizards with low testosterone concentrations is that these lizards perform more territorial behaviors, have increased movements, and larger home range sizes, thus exposing them to more parasites. Several studies have shown testosterone to increase the frequency of behaviors, movement, and home range size in lizards, but few, if any, have related it to ectoparasite intensities. Here I tested two hypotheses: 1. High testosterone male lizards have larger home ranges than male lizards with lower testosterone concentrations and female lizards. 2. High testosterone male lizards perform a higher frequency of territorial behaviors than male lizards with lower testosterone concentrations and female lizards. To test these hypotheses I implanted male lizards with either testosterone or blank-control implants, left female lizards unaltered, and performed behavioral observations in the field for 25 days. At the end of this time period, home range sizes were calculated as minimum convex polygons and ectoparasite intensities were quantified. Results of this study revealed no significant difference in ectoparasite intensities between high and low testosterone male lizards, but male lizards did have significantly higher ectoparasite intensities than female lizards. Furthermore, home range size and frequencies of territorial behaviors were not significantly different between high and low testosterone male lizards. However, male lizards did have larger home ranges and performed more territorial behaviors and movements than female lizards. These results suggest that home range, movement, and territorial behavior frequency contribute to higher ectoparasite intensities on male lizards, particularly those on males with high circulating testosterone. However, future studies need to address the behavioral and physiological mechanisms responsible for the observed effects of testosterone on parasitism, including parasite intensity, immunosuppression, and parasitic effects on host fitness.

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Simó, Riudalbas Marc 1988. "An Integrative approach to the systematics and evolution of some selected reptile groups from Arabia." Doctoral thesis, Universitat Pompeu Fabra, 2018. http://hdl.handle.net/10803/664731.

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Until relatively recently, many groups of terrestrial reptiles were considered to contain only few species vastly distributed across the Arabian Peninsula. This was mostly the result of the apparent morphological uniformity of these groups in combination with their geographic ranges, often overlapping with politically unstable regions in which scientific research has been hampered for centuries. However, our understanding of the diversity inhabiting these unexplored areas changed with the onset of molecular phylogenetic methods that became extensively available and routinely applied to tackle a broad set of evolutionary questions. This thesis focuses on resolving the systematics, biogeography and evolution of four selected groups of reptiles from Arabia, using an unprecedented sampling of over 1,000 tissues for genetic analyses and more than 900 voucher specimens. For some taxa, we inferred time-calibrated phylogenies, and we reconstructed their biogeographical history and their morphological evolution. For many others, we unexpectedly discovered high levels of genetic diversity and several lineages potentially representing unknown species. In the latter case, testing different species delimitation methods led to more detailed examination of the genetic, morphological and ecological data in order to resolve the taxonomy of these candidate species. As a result of that, four new species of geckos and two lacertid lizards have been formally described as part of this thesis. Essentially, most of the new species were found in the mountain regions of Arabia, stressing the importance of these poorly studied areas as recognized hotspots in terms of reptile diversity and endemicity.
Fins fa relativament poc, es considerava que la majoria de grups de rèptils terrestres comprenien només unes poques espècies àmpliament distribuïdes per tota la Península Aràbiga. Aquesta percepció es devia, en gran part, a l’aparent uniformitat morfològica d’aquests grups i les seves àrees de distribució geogràfica, sovint coincidents amb regions políticament inestables on la investigació científica s’ha vist limitada durant segles. No obstant, el coneixement que teníem sobre aquestes àrees poc explorades va canviar amb l’aparició de les filogènies moleculars, aviat àmpliament disponibles i aplicades de manera rutinària per abordar un nou ventall de qüestions evolutives. Aquesta tesi doctoral es centra en resoldre la sistemàtica, la biogeografia i l’evolució de quatre grups concrets de rèptils, utilitzant un mostreig sense precedents que inclou més de 1.000 teixits analitzats genèticament i més de 900 espècimens. Per alguns tàxons, hem inferit filogènies calibrades tot reconstruint la seva història biogeogràfica i la seva evolució morfològica. Per a d’altres, hem descobert inesperadament alts nivells de diversitat genètica i diversos llinatges que podrien representar espècies desconegudes. En el darrer cas, l’ús de diferents mètodes de delimitació d’espècies va conduir a examinar més detalladament les dades genètiques, morfològiques i ecològiques per tal de resoldre la taxonomia d’aquestes espècies candidates. Com a resultat, quatre espècies de dragons i dues sargantanes de la família dels lacèrtids han estat formalment descrites en el decurs d’aquesta tesi. Donat que la majoria d’aquestes espècies habiten a diferents zones muntanyoses d’Aràbia, aquesta tesi destaca la importància d’aquestes regions com a punts calents de diversitat biològica i endemicitat pel que fa a la seva fauna reptiliana.

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Moore, Sara W. M. "Isolation, structural characterisation and mode of action of bioactive agents from arachnid and reptile venoms." Thesis, Ulster University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.673816.

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Selected snake and spider venom fractions were screened for in-vitro insulinotropic activity in glucose responsive BRIN-BDll cells, with insulin secretion measured using radioimmunoassay. Significant insulin secretion was noted for 27 snake venom fractions, containing a diverse range of snake toxin families including phospholipases A2, a-neurotoxins, disintegrins, serine proteinases, CRISP (cysteine-rich secretory proteins), metalloproteinases and nucleotidases. The partial N-terminal sequences are reported for 15 snake venom components. Elevated levels of insulin secretion were recorded for 16 fractions from the Grammostola rosea venom and 31 fractions from the Aphonopelma chalcodes venom. The synthetic version of a novel 28 amino acid residue peptide isolated from the Aphonopelma chalcodes produced a significant concentration dependent increase in insulin secretion. A number of theraphotoxins are proposed as constituents of the active Aphonopelma chalcodes fractions. Paliial sequences are presented for 3 unknown Grammostola rosea peptides with insulinotropic activity reported as a novel function of a number of known Grammostola peptides. A microtitre assay was used to assess antimicrobial activity of snake and spider venom against both Gram-positive and Gram-negative bacteria. Snake venom fi.-actions containing an L-amino acid oxidase or metalloproteinase component showed preferential activity against Staphylococcus aureus, while phospholipases A2 were most active against Bacillus subtilis. Activity against Salmonella typhimurium was greatest for fractions containing L- amino acid oxidase. Escherichia coli was least susceptible to the test fractions. Antimicrobial activity for the Aphonopelma chalcodes crude venom was confmed to fractions 26 to 35, containing low mass compounds of mJz 730- 830 alongside a peptide component of mJz 2919, for which the novel sequence is reported. A quantitative study was performed on the selected low molecular mass components isolated ill the Hap/ope/rna lividurn spider venom usmg liquid chromatography / electro spray ionisation mass spectrometry. This study of the bioactive constituents of snake and spider venom serves to enhance the existing body of evidence supporting the study of venomics in pursuit of novel leads for pharmaceutical research and development.

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Sanders, Colin E. "Quiescent states of sleep, torpor and hibernation in the." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2331.

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Brazilian tegus (Tupinambis merianae) were instrumented with telemetry encoder implants that measured and broadcast heart rate (HR), breathing rate (fR), and deep body temperature (Tb) and were then allowed to freely roam in outdoor enclosures mimicking their natural environment for a full year (2004) in order to monitor the circadian and circannual patterns in behaviour and cardio-respiratory physiology. The year was divided up into 5 seasons based upon the physiology and behaviour of the tegus: early activity season (Sept.-Nov.), late activity season (Dec.-Feb.), entrance into hibernation (March-April), hibernation (May-July), and arousal from hibernation (August). The activity seasons were characterized by warm weather with frequent rainfall which slowly decreased in temperature and precipitation as tegus started entering hibernation so that the end of the dormant season was marked by dry, cold weather. Tegus in the early activity season demonstrated high activity associated with breeding demands, displayed elevated HR and fR, and were able to maintain a large temperature differential (4-7°C) between deep body temperature (Tb) and their respective burrow (Tburrow) during sleep. As the season progressed into late activity season, average Tb remained constant but average HR and fR progressively declined indicating nightly torpor. Periods of inactivity during the active seasons were rare and associated with inclement weather. Tegus entered hibernation through bouts of inactivity that progressively increased in frequency and duration. During this time, Tb was regulated but declined at different rates in regards to daytime and nighttime values. Heart rate through the entrance into hibernation and hibernation periods frequently demonstrated arrhythmias that increased in duration but decreased with frequency as hibernation progressed. Through hibernation, Tb continued to decline for the first month but HR and fR were constant, demonstrating a temperature independent suppression of metabolism. Through the hibernation season tegus sporadically aroused and emerged from their burrows to warm up and after a short basking period would return to the burrows and swiftly resume hibernation. While hibernating, heart rate was characteristically regular but breathing was sporadic orepisodic. Arousals became more frequent towards the end of hibernation so that when they entered arousal from hibernation season most tegus were emerging daily. At this time daily maximum deep body temperature (Tbmax) swiftly returned to active season values but nighttime daily minimum deep body temperature (Tbmirt) values only showed a gradual increase through August, indicating different body temperature set points (Tbset) for active and sleep states. Changes in heart rate and breathing rate during the year showed greatest correlation with changes in photoperiod, although throughout hibernation HR and fR also showed tight correlation with Tb.

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Gorissen, Sarsha. "Conservation biology of the endangered Blue Mountains Water Skink (Eulamprus leuraensis)." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15731.

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The Blue Mountains Water Skink (Eulamprus leuraensis), restricted to the endangered habitat of highland peat-swamps, is known from fewer than 60 isolated sites in the Blue Mountains region of south-eastern Australia. The sole endemic vertebrate of the region, this scincid lizard is imperilled by many threats. From three years of field surveys, I show that E. leuraensis live almost exclusively within swamps, with very few inhabiting the swamp margins and none recorded in the surrounding woodland. Paradoxically, this endangered species appears to be the most abundant vertebrate in these swamps. My surveys show that urbanisation and frequent major fires both reduce the abundance of these skinks, but do not extirpate them. A longer period of time since a major fire, conversely, increases the abundance of this reptile. Groundwater loss and alterations in surface water chemistry extirpate populations of this species: its restriction to groundwater-dependent swamps renders it highly sensitive to habitat degradation through hydrological disturbance. To conserve E. leuraensis in the wild, we need to protect its swamp habitat from the impacts of urbanisation, intensified fire regimes, reduced groundwater, water pollution and longwall mining. The conservation message for management authorities is clear: ‘protect the habitat, protect the skink.’

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Guzinski, Jaro, and guzi0002@flinders edu au. "Investigating genetic population substructure of an Australian reptile tick, Bothriocroton hydrosauri, using highly polymorphic microsatellite markers." Flinders University. School of Biological Sciences, 2009. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20090324.125811.

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Despite long-term study, the mechanism explaining the parapatric distribution of two Australian reptile ticks species, Bothriocroton hydrosauri and Amblyomma limbatum, is not understood. This project aimed to use molecular genetic data to investigate aspects of the population biology of these two tick species, such as population structure and dispersal, to gain further insights into the cause and maintenance of this parapatric boundary. I developed and subsequently tested for Mendelian inheritance a suite of B. hydrosauri and A. limbatum species-specific microsatellites markers. Pedigree analysis showed one B. hydrosauri locus and all of the A. limbatum loci to be inherited in a non-Mendelian manner. Thus I could not investigate A. limbatum population structure and focused solely on B. hydrosauri. The first part of this study tested predictions of a model formulated to explain B. hydrosauri transmission dynamics. The ripple model, based on detailed ecological and behavioural data on B. hydrosauri and Tiliqua rugosa, B. hydrosauris most common host, predicts higher relatedness among larvae than among nymphs or adults on a host, and significant spatial autocorrelation in larvae extending further than for the later life stages. The model also predicts that adult ticks are likely to encounter related partners and that this will generate inbreeding within the population. I tested those predictions using nine microsatellite loci on a sample of 848 ticks (464 larvae, 140 nymphs and 244 adults) collected from 98 T. rugosa hosts at the northern edge of B. hydrosauris distribution range. My data did support all of the predictions of the ripple model and indicated that the dynamics of transmission among hosts play an important role in parasite population structure. The second part of this project focused on investigating the population genetic structure of B. hydrosauri at the edge of its geographic range and testing the predictions of a population model derived to explain B. hydrosauris parapatric boundary with A. limbatum. The ridge and trough model suggested the tick population was organised spatially into a series of ridges where tick density was high and troughs where it was low. Genetically, the expectation was to find clusters of more closely related individuals associated with the ridges. Cluster analysis of microsatellite allele frequencies and analysis of molecular variance of mitochondrial haplotype frequencies revealed the presence of four genetic clusters within a sample of 244 B. hydrosauri adults. As the highly genetically divergent clusters had overlapping distributions, and in some cases were syntopic, the genetic population structure predicted for these ticks by the ridge and trough model was not observed. Several explanations were considered for the observed B. hydrosauri genetic population structure, but syntopy of the clusters suggested that assortative mating is the most likely. I speculated that the clusters have formed in allopatry, when the environment was extremely heterogeneous, such that the ticks (and their hosts) were confined to isolated patches of high-quality habitat. Given sufficient time, this could have resulted in reproductive incompatibility between ticks occupying different patches. The population structure I uncovered indicates subsequent secondary recontact of divergent groups. Although my study allowed for a better understanding of B. hydrosauri biology and population structure, the reasons for the parapatric distributions of B. hydrosauri and A. limbatum are still unclear. Further research should focus on investigating the population genetic structure of A. limbatum at the edge of its range, as well as on performing a larger-scale study of B. hydrosauri population genetic structure and a more detailed investigation of the applicability of the ridge and trough model to this tick species. Moreover, it will be useful to inspect the population structure of both these species within the centers of their ranges and compare these findings with population structure found at the edge of the range.

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Källsten, Lena. "Diversity and Ecology of a Middle Campanian (Late Cretaceous) Marine Reptile Assemblage from Skåne, Southern Sweden." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-262267.

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This study has looked at an assemblage of fossilised teeth from Mesozoic marine amniotes from the Kristianstad basin in southern Sweden in order to make an estimate of the ecomorph diversity within said assemblage through looking at the morphology of the teeth. This was done as a pilot study to see if further studies would be able to produce worthwhile results. The assemblage consists largely of isolated tooth crowns, mostly from small- to medium sized mosasaurs such as Clidastes and Eonatator, but also contains larger mosasaurs, as well as a couple of plesiosaurs and one species of a marine crocodile. The analysis was performed on images of teeth using software developed for use in morphometrics. The resulting graphs imply a division into three guilds; the first represented by the short and blunt teeth of the crocodilian, the second by the elongated teeth of the plesiosaurs, and the third by the knife-like teeth of the mosasaurs. Since the mosasaurs overlap to a high degree in tooth shape, but also show quite diversity in size, it is possible the main dividing factor would have been size rather than type of prey. Further studies would be able to get a more accurate image of the ecology of this fauna by increasing the number of specimen in the analysis as well as taking into consideration more factors from other studies of similar taxa, such as jaw sizes, bite marks and gut contents.
Det här arbetet har studerat fossila tänder tillhörande Mesozoiska marina amnioter från Kristianstadsbassängen i södra Sverige, med avsikt att göra en uppskattning av den ekomorfa spridningen inom gruppen genom att studera tändernas form. Detta är enbart en pilotstudie för att se om fortsatta studier kan ge givande resultat. Det studerade materialet är en del av en samling till stor del bestående av enbart lösa tandkronor, mest från små till medelstora mosasaurier, såsom Clidastes och Eonatator, men även från större mosasaurier, så väl som ett par plesiosaurier och en marin krokodil-art. För analysen användes en programvara specifikt utvecklad för morfometri. De resulterande graferna antyder en indelning i tre “gillen”; det första representeras av de korta och trubbiga tänderna tillhörande krokodilen, det andra av de långsmala tänderna hos plesiosaurierna, och det tredje av de knivlika mosasaurietänderna. Eftersom mosasaurierna överlappar till stor grad gällande formen på tänderna, men skiljer sig mycket åt i storlek, så är det troligt att det snarare var storleken på bytesdjuren, och inte vilken typ, som skiljde dem åt. Framtida studier skulle kunna ge en bättre bild av den här faunans ekosystem dels genom att inkludera fler exemplar i analysen, och dels genom att inkludera andra faktorer från studier av liknande taxa, såsom käkstorlek, bitmärken och maginnehåll.

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Harper, Jack. "Assessing the climate change vulnerability of reptile and amphibian species found in Table Mountain National Park." Master's thesis, University of Cape Town, 2020. http://hdl.handle.net/11427/32495.

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It is increasingly apparent that climate change and its associated impacts are a major threat to the rich biodiversity of the Cape floristic region. As the knowledge of the associations between biological traits and climate change impacts strengthens it has become clear that the assessment of climate change vulnerability is a key consideration in the management of biodiversity. This study is the first attempt to use a trait-based approach at the scale of a single national park, focusing on the climate change vulnerability of reptile and amphibian species found in Table Mountain National Park (including historically present species). The park and its immediate surrounding areas are home to a rich diversity of herpetofauna including the Critically Endangered Table Mountain ghost frog (Heleophryne rosei), Rose's mountain toadlet (Capensibufo rosei) and micro frog (Microbatrachella capensis), and the Endangered western leopard toad (Sclerophrys pantherina). Amphibian and reptile-specific assessment frameworks of biological and ecological traits were designed to identify the species most sensitive and least able to adapt to climate change pressures. Using a combination of a literature review and expert consultation, 18 species of amphibian and 41 species of reptile were assessed. The assessment highlighted that, in the worst-case scenario, 85% of the park's reptile species and 67% of the park's amphibian species are predicted to be highly vulnerable to climate change. The southern adder (Bitis armata), Cape long-tailed seps (Tetradactylus tetradactylus), Table Mountain ghost frog (Heleophryne rosei) and the Lightfoot's moss frog (Arthroleptella lightfooti) were identified as being the species most vulnerable to climate change within their respective taxa. All three of the Critically Endangered amphibian species were identified as having both high sensitivity and low adaptive capacity to climate change. Among the focal reptile species, climate change vulnerability was independent of current IUCN Red List status, highlighting that species currently not identified to be under threat by other anthropogenic pressures could imminently become threatened by climate change. Spatiallyexplicit presentation of the assessment output will help prioritise the management of areas within Table Mountain National Park that contain a high diversity of climate-vulnerable species. By reducing the threats from other human-associated impacts to these species, and by identifying when direct intervention is appropriate, the park's management can give these species the best opportunity of persistence in an uncertain climate future.

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Loughman, Zachary James. "Natural history and conservation biology of a southern West Virginia contour surface mine reptile and amphibian community." Huntington, WV : [Marshall University Libraries], 2005. http://www.marshall.edu/etd/descript.asp?ref=585.

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Hutchens, Stan Jonathan. "Inventory and Assessment of the Reptile and Amphibian Community of Bull Neck Swamp, Washington County, North Carolina." NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-02012008-151409/.

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Recent declines in reptile and amphibian populations across the globe have encouraged an increased desire to discover, document, and monitor these taxa. Arguably, the greatest cause is land-use change. Management interests for Bull Neck Swamp (BNS) encouraged research to inventory the reptile and amphibian community and to document possible impacts of land-use practices, such as silviculture and site preparation. Four habitat preserves were delineated based on plant community, leaving 1, 554ha (3, 841ac) available for management. Comparisons between habitat assemblages were used to determine if preserves were occupied by more vulnerable species and land-use effects on these species. However, variations in behavioral or environmental variables, and detection probabilities between capture techniques could provide misleading data for assemblage comparisons of community parameters. Therefore, 11 different capture techniques were employed to obtain better samples of habitat assemblages. To determine the accuracy of sampling techniques at inventorying species, techniques were categorized into primary (i.e., drift fence arrays with pitfall and funnel traps, visual encounter surveys, and coverboard arrays), secondary (i.e., road searches, polyvinyl chloride (PVC) piping grids, auditory surveys, and line transects), and tertiary (opportunistic encounters, aquatic funnel traps, crayfish traps, and basking traps) methodologies. All techniques had variable distributions and were evenly represented in all five areas when possible. All captured individuals were marked; snakes were double-marked with visible implant fluorescent elastomer to augment a concomitant laboratory experiment. Initial capture data were used to derive estimates of species richness (S) and modified Chao - Jaccard similarity indices (JSI). During May to August, 2005 and 2006, 1, 581 total captures represented 33 species, giving an estimated species richness of 34. Primary techniques sampled an estimated species richness of 14 and two unique species, species detected by only one sampling technique. Estimated species richness for secondary and tertiary techniques was 29 and 25, with three and seven unique species, respectively. If primary techniques alone were used, 59% of the reptile and amphibian community, including 10 unique species, would have been missed. Observed and estimated species richness for habitats ranged from 7 to 32 and 13 to 44, respectively. Chao â Jaccard similarity indices ranged from 0.59 to 1.0, with nine comparisons over 0.75, which indicated high similarity between habitat assemblages. These results suggested that land-use practices should be carefully planned and implemented to reduce effects to the reptile and amphibian community of BNS. Empirical results supported the use of elastomers for snakes. It is recommended that future inventory studies for all taxa employ as many capture techniques as logistically and spatially possible to derive accurate species richness. Also, assemblage comparisons should rely on species composition when determining conservation plans.

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Wu, Weibin [Verfasser]. "Tribological characterization of reptile scales and their application as technical surfaces with tunable friction anisotropy / Weibin Wu." Karlsruhe : KIT-Bibliothek, 2020. http://d-nb.info/1219577855/34.

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Dittmer, Drew E., Trevor L. Chapman, and Joseph R. Bidwell. "In the Shadow of an Iconic Inselberg: Uluru's shadow Influences Climates and Reptile Assemblage Structure at its Base." Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/etsu-works/7196.

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Uluru is the more famous of the two namesake inselbergs found in Uluru Kata-Tjuta National Park (UKTNP). Uluru is roughly 10 km around its base, stands nearly 350 m tall, and can cast a shadow more than a kilometre long during the early morning and late afternoon hours. Additionally, there are many areas near the base of Uluru that receive nearly continuous shade throughout the day, which may also mean that these places could be buffered against extreme temperatures. This study investigated Uluru's influence on the climate at various distances from its base, and simultaneously assessed if the structure of the reptile community was related to the observed climatic variation. We used iButton data loggers to record the temperature and relative humidity at 26 sample locations surrounding Uluru. We used ArcGIS to map the path of Uluru's shadow and to determine when and how long data loggers recorded in and out of Uluru's shading influence. We found that the temperature and relative humidity were strongly influenced by Uluru's shadow, and that reptile assemblages were strongly correlated with the amount of time a sampled site was influenced by Uluru's shadow.

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Monsinjon, Jonathan. "Développement embryonnaire, détermination du sexe sensible à la température et phénologie des pontes sous contrainte du changement climatique : le cas de la tortue Caouanne (Caretta caretta)." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS510/document.

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Le climat affecte entre autre la phénologie, l’aire de distribution, le comportement et la physiologie des espèces. Le changement climatique a donc des répercussions sur chacun de ces facteurs. L’augmentation globale des températures prévue d’ici 2100 pourrait profondément modifier la biodiversité de l’échelle des espèces jusqu’à celle des écosystèmes. Les ectothermes, et en particulier les reptiles ovipares à détermination du sexe sensible à la température, font partie des organismes susceptibles d’être les plus vulnérables au réchauffement du climat puisque quasiment tous leurs traits d’histoire de vie dépendent de la température. L’origine et le maintien de ce mécanisme de détermination du sexe, pouvant conduire à un sex ratio fortement biaisé à l’échelle d’une population, reste une énigme pour les écologues. Parmi les nombreuses questions soulevées par la présence de ce mécanisme de détermination du sexe, la signification adaptative, s’il y en a une, de ce mécanisme est cruciale.Ce mécanisme de détermination du sexe rend-il les espèces plus vulnérables dans le contexte actuel du changement du climat ? Plusieurs hypothèses évolutives ont été proposées et des modèles de dynamique des populations sont disponibles pour répondre à ces questions. Cependant, prédire le sex ratio primaire en conditions naturelles, c’est-à-dire le sex ratio des nouveaux nés, reste un défi majeur à l’heure actuel. Ce manuscrit vise à apporter de nouveaux outils méthodologiques afin de correctement prédire le sex ratio d’une ponte en fonction de la température ressentie par les embryons au cours de l’incubation. Les tortues marines,quasiment toutes menacées, sont des espèces migratrices présentant toute ce mécanisme de détermination du sexe.Chez ces espèces, la phénologie des pontes est aussi sensible à la température du milieu. Ce type de plasticité phénotypique est probablement la stratégie la plus efficace pour pallier à un changement rapide du climat. Ce manuscrit apporte quelques éléments de réponse quant au potentiel adaptatif des tortues marines face au réchauffement climatique avec l’exemple de plusieurs populations de tortues Caouanne (Caretta caretta)
Climate affects, among other things, species’phenology, distribution range, behavior and physiology.Climate change thus impacts each of these factors. Global warming expected by 2100 might profoundly modify biodiversity from species to ecosystems. Ectotherms, and in particular oviparous reptiles with temperature dependent sex determination, are thought to be among the most vulnerable in the face of global warming because virtually all their life history traits depend on temperature.The origin and the persistence of temperature-dependent sex determination, which could lead to heavily biased population sex ratios, is still an enigma for ecologists. Among numerous issues related to this sex determining mechanism, understanding its adaptive significance, if there is one, is crucial. At another level, does this sex determining mechanism make species more vulnerable in the context of contemporary climate change ? Several evolutionary hypotheses have been proposed and population dynamic models are available to address these issues. However, predicting primary sex ratio, i.e., the sex ratio of hatchlings, in natural conditions currently remainsa challenge. This manuscript aims to bring new methodological tools to properly predict sex ratio of aclutch depending on temperature experienced by embryosthroughout incubation. Marine turtles, almost all being threatened, are migratory species that all exhibit this sex determining mechanism. For those species, nesting phenology is also sensitive to environmental temperature.This type of phenotypic plasticity is probably the most efficient strategy to keep up with rapid climate change.This manuscript provides some elements for understanding the adaptive potential of sea turtles in the face of global warming with the example of several)

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Melero, Jurado Adrián. "Anatomical description of the coelomic cavity organs using radiography, ultrasonography and computed tomography in healthy veiled chameleons (Chamaeleo calyptratus) and panther chameleons (Furcifer pardalis)|Descripción anatómica de los órganos de la cavidad celómica mediante radiografía, ecografía y tomografía computerizada en camaleones velados (Chamaeleo calyptratus) y camaleones pantera (Furcifer pardalis) sanos." Doctoral thesis, Universitat Autònoma de Barcelona, 2020. http://hdl.handle.net/10803/670673.

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El camaleó vetllat (Chamaeleo calyptratus) i el camaleó pantera (Furcifer pardalis) són dues de les espècies de camaleó més populars al món, i en conseqüència, dues de les que més freqüentment s’atenen a les consultes veterinàries. Les diferents tècniques de diagnòstic per imatge solen incloure’s de forma rutinària als protocols diagnòstics en medicina herpetològica com són la radiografia, la ecografia, la tomografia computeritzada y la ressonància magnètica. Tot i així, els estudis publicats sobre descripció anatòmica mitjançant tècniques d’imatge són escassos, i la interpretació d’aquestes últimes es basa en l’experiència pròpia del clínic o bé per extrapolació d’altres espècies prèviament estudiades. Per aquest motiu, els objectius d’aquest estudi anatòmic prospectiu van ser desenvolupar protocols de diagnòstic per imatge en aquestes espècies i descriure l’anatomia dels òrgans de la cavitat celòmica en animals sans, mitjançant l’ús de la radiografia, l’ecografia i la tomografia computeritzada. Es van incloure disset camaleons vetllats (7 mascles i 10 femelles) i quinze camaleons pantera (13 mascles i 2 femelles) sans en base als resultats de l’examen físic general i de l’estudi corològic. L’estudi es va realitzar en camaleons sedats mitjançant l’administració d’alfaxalona (Alfaxan®, Crawley, UK) 4-6 mg/kg IV a la vena ventral de la cua. Un cop sedats, es va realitzar un estudi radiogràfic amb dues projeccions (lateral dreta i dorsoventral) amb xassís de mamografia. Seguidament, es va realitzar un estudi ecogràfic complet de la cavitat celòmica amb l’ús de sonda lineal de 15 a 18-MHz en decúbit lateral dret. Finalment, es va realitzar una tomografia computeritzada helicoidal amb un escàner de 16 talls en decúbit esternal. Es va realitzar l’estudi postmortem d’un exemplar de cada espècie per tal d’aclarir, il·lustrar i avaluar les troballes de les proves d’imatge. Els resultats obtinguts suggereixen que les diferents tècniques d’imatge estudiades permeten la visualització del fetge (incloent la vena cava caudal i las venes hepàtiques), la vesícula biliar, l’estómac, els intestins, les gònades, els cossos grassos i els ronyons en camaleons vetllats i pantera. La bufeta de la orina només es va identificar mitjançant ecografia i tomografia. La melsa, el pàncrees i les glàndules adrenals van ser identificades als estudis postmortem però no van poder visualitzar-se mitjançant cap tècnica d’imatge. En conclusió, aquest estudi proporciona una guia de les característiques anatòmiques normals dels òrgans celòmics mitjançant tècniques de diagnòstic per imatge en camaleons vetllats i camaleons pantera. D’aquesta manera, les troballes poden ser utilitzades com a referència durant els exàmens de pacients malalts o per a futurs estudis d’investigació.
El camaleón velado (Chamaeleo calyptratus) y el camaleón pantera (Furcifer pardalis) son dos de las especies de camaleón más populares en el mundo, y en consecuencia, dos de las que más frecuentemente se atienden en la consulta veterinaria. Las diferentes técnicas de diagnóstico por imagen suelen incluirse de forma rutinaria en los protocolos diagnósticos en medicina herpetológica, entre ellas la radiografía, la ecografía, la tomografía computerizada y la resonancia magnética. Sin embargo, los estudios publicados sobre descripción anatómica mediante técnicas de imagen son escasos, y la interpretación de estas últimas se basa en la experiencia propia del clínico o bien por extrapolación de otras especies ya estudiadas. Por este motivo, los objetivos de este estudio anatómico prospectivo fueron desarrollar protocolos de diagnóstico por imagen en estas especies y describir la anatomía de los órganos de la cavidad celómica en animales sanos, mediante el uso de radiografía, ecografía y tomografía computerizada. Se incluyeron diecisiete camaleones velados (7 machos y 10 hembras) y quince camaleones pantera (13 machos y 2 hembras) sanos en base a los resultados del examen físico general y del estudio coprológico. El estudio se realizó en camaleones sedados tras la administración de alfaxalona (Alfaxan®, Crawley, UK) 4-6 mg/kg IV en la vena ventral de la cola. Una vez sedados, se realizó un estudio radiográfico con dos proyecciones (lateral derecha y dorsoventral) con chasis de mamografía. Seguidamente, se realizó un estudio ecográfico completo de la cavidad celómica mediante sonda lineal de 15 a 18-MHz en decúbito lateral derecho. Finalmente, se realizó una tomografía computerizada helicoidal con un scanner de 16 cortes en decúbito esternal. Se realizó el estudio post mortem de un ejemplar de cada especie por tal de esclarecer, ilustrar y evaluar los hallazgos de imagen. Los resultados obtenidos sugieren que las diferentes técnicas de imagen estudiadas permiten la visualización del hígado (incluyendo la vena cava caudal y las venas hepáticas), la vesícula biliar, el estómago, los intestinos, las gónadas, los cuerpos grasos y los riñones en camaleones velados y pantera. La vejiga de la orina solo pudo identificarse mediante ecografía y tomografía. El bazo, el páncreas y las glándulas adrenales fueron identificados en los estudios post mortem pero no pudieron ser visualizados mediante ninguna de las técnicas de imagen. En conclusión, este estudio proporciona una guía de las características anatómicas normales de los órganos celómicos mediante técnicas de diagnóstico por imagen en camaleones velados y camaleones pantera. De esta forma, los hallazgos pueden ser utilizados como referencia para exámenes de pacientes enfermos o para futuros estudios de investigación.
Veiled chameleon (Chamaeleo calyptratus) and Panther chameleon (Furcifer pardalis) are the most popular chameleons over the world, and consequently, two of the most frequently species attended in veterinary practice. The most commonly used imaging techniques in diagnostic protocols in herpetology include radiography, ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI). However, few studies about imaging description in reptiles have been published. The objectives of this prospective anatomic study were to develop imaging techniques for these species and to describe the normal anatomy of the coelomic organs using radiography, US and CT scan. Seventeen healthy veiled chameleons (7 males and 10 females) and fifteen healthy panther chameleons (13 males and 2 females) were included in the study. Animals were considered to be healthy on the basis of the results of a complete physical examination and coprology testing. The imaging study was performed in sedated chameleons after the administration of alfaxalone (Alfaxan®, Crawley, UK) 4-6 mg/kg IV in the ventral vein of the tail. A right lateral and dorsoventral radiographic views were performed with a mammography cassette plate in all animals. Then, an ultrasound was performed in right lateral recumbency using a linear 15 to 18-MHz transducer. Finally, a CT examination was performed with a 16-slice helical CT scanner in sternal recumbency. Post-mortem study of one chameleon of each species were used to clarify and illustrate coelomic anatomy and to assess imaging findings. The results of the current study suggest that the different imaging techniques (radiography, ultrasonography and computed tomography) allow the visualization of the liver (including caudal vena cava and hepatic veins), gallbladder, stomach, intestines, gonads, fat bodies and kidneys in healthy veiled and panther chameleons. The urinary bladder was identified using US and CT examination. The spleen, pancreas and adrenal glands were identified in post-mortem studies, but could not be visualized with any imaging technique. In conclusion, this study provides a guide of the normal imaging anatomic features of the coelomic organs in veiled chameleons and panther chameleons. Findings can be used as a reference for future research studies or for examinations of clinically ill patients.

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Metallinou, Margarita. "Systematics, biogeography and evolution of selected widespread reptile genera from the arid areas of North Africa and Arabia." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/277485.

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The arid areas of North Africa and Arabia cover a surface of more than 13 million square kilometers and are characterized by their extreme temperatures, diversity of desert habitats and well-adapted flora and fauna. The study of the evolution of their biota sheds light on the diversification processes in some of the world’s harshest environments and contributes to our knowledge on large-scale biogeographic patterns and processes. The general aim of this dissertation is to investigate the evolution of the biota of the arid areas of North Africa and Arabia, through the study of the systematics and biogeography of two representative reptile groups, Stenodactylus and Ptyodactylus. The geckos of these two genera are among the most common faunal elements of the arid North African and Arabian environments, yet they are very distinct with regard to their morphology, ecology and patterns of species divergence. On the one hand, the naked toe Stenodactylus species are relatively divergent morphologically and have conquered different arid and hyper-arid habitats across plains or dunes. On the other hand, Ptyodactylus geckos are fairly conserved morphologically across their entire range and are very well adapted to a common type of structural habitat characterized by the rocky substrate. The results presented herein provide a thorough insight into their phylogenetic relationships, review and update their taxonomy, explore their historical biogeography and, altogether, assemble a broader image of diversity patterns within a temporal framework for the arid North Africa and Arabia. Highlighting the most relevant results, in this dissertation an unprecedentedly large set of samples from North Africa, the Sahel and Arabia was compiled for the two selected groups of study: 249 samples of Stenodactylus from 150 localities and 382 samples of Ptyodactylus from 221 localities. Regarding molecular data, 770 DNA sequences of five different markers were newly produced for the former genus, and 1443 of six different markers for the latter. Stenodactylus originated in Arabia in the Late Oligocene. The Arabian Clade B, including five species, and the mainly African Clade C, with the same number of species, split approximately 22 Ma ago, coinciding with the opening of the Red Sea. Diversification within several clades in the phylogeny occurred during the Late Miocene, a time when a general increase in aridification initiated. Based on mitochondrial and nuclear molecular data, as well as morphological characters, a new species of Stenodactylus is described. Stenodactylus sharqiyahensis sp. nov. is shown to be endemic to the sand desert of Al Sharqiyah, in northeastern Oman. Nomenclatural actions undertaken for the stability of the nomina of North African species of Stenodactylus include the designation of a lectotype for the nomen Stenodactylus guttatus which places it under the synonymy of P. hasselquistii, ensuring continuity of the prevailing usage of S. petrii, and the application to the International Commission of Zoological Nomenclature to accept a new name-bearing type for S. sthenodactylus, in order to maintain its prevailing usage. Regarding Ptyodactylus, its broad sampling includes numerous new records for some of the species, and especially for the P. hasselquistii species complex, an important extension of its known distribution range both in northeastern Africa and Arabia. All the formerly known and newly-delimited species are shown to be mostly allopatric, except some known cases where activity patterns are adjusted to avoid competition. This is hypothesized to relate to their preference for the same type of structural habitat, conditioning their apparently conserved morphology. The onset of the diversification in the genus Ptyodactylus is estimated to have taken place in the Late Oligocene. In the northeastern African and Arabian clades A, B and C, diversification started during the Late Miocene, approximately 9.5-12 Ma ago, posterior to that in the western African P. togoensis and P. oudrii. The molecular data show that many species have high levels of genetic variability. Ptyodactylus ragazzii presents two clades in the phylogeny, from East and West Africa respectively, and given that topological tests reject their sister relationship, the available name P. togoensis is assigned to the West African populations. Multilocus coalescence-based analyses with the use of GMYC and BPP methodologies result in the delimitation of 17 putative species in the P. hasselquistii species complex. These species are grouped in two major clades: Clade A, with nine species, is distributed across northeastern Africa and a large part of north, central and eastern Arabian Peninsula, and Clade B, with eight species, is restricted to southern Arabia.
Les zones àrides del Nord d'Àfrica i d'Aràbia s'estenen per diversos milions de kilòmetres quadrats i l'estudi en aquesta àrea dels patrons de biodiversitat a gran escala, es veu condicionat de forma essencial per la dificultat d'obtenir un mostreig complet, per l'escassa informació de la seva biota i per la complexitat dels processos que han generat la biodiversitat actualment existent. En el marc limitat d'una tesi doctoral, i considerant les premisses anteriorment descrites, s'han seleccionat dos gèneres de rèptils àmpliament distribuïts en aquestes àrees, el gènere Stenodactylus i el Ptyodactylus. Ambdós gèneres formen part dels elements més comuns de la fauna del Nord d'Àfrica i d'Aràbia, malgrat presentar importants diferències pel que fa a la seva morfologia, ecologia i patrons de divergència. Per un costat, les espècies dels dragons del gènere Stenodactylus són relativament divergents entre elles respecte a la morfologia, i han conquistat diferents ambients àrids i hiperàrids, incloent-hi alguns dels entorns més hostils dels deserts. Per altra banda, els dragons del gènere Ptyodactylus són més aviat conservats pel que fa a la morfologia, sempre presentant els característics coixinets triangulars dividits en múltiples làmines en les seves potes, i estan ben adaptats als substrats rocosos, que constitueixen el seu hàbitat estructural. Els resultats aquí presentats aporten un coneixement profund en les seves relacions filogenètiques, es revisa i s'actualitza la seva taxonomia, s'explora la seva biogeografia històrica, i en conjunt, es dona una imatge general dels patrons de diversitat dins d'un marc temporal pels ambients àrids del Nord d'Àfrica i d'Aràbia.

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Wasiolka, Bernd. "The impact of overgrazing on reptile diversity and population dynamics of Pedioplanis l. lineoocellata in the southern Kalahari." Phd thesis, Universität Potsdam, 2007. http://opus.kobv.de/ubp/volltexte/2008/1661/.

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Die Vegetationskomposition und –struktur, beispielsweise die unterschiedliche Architektur von Bäumen, Sträuchern, Gräsern und Kräutern, bietet ein großes Spektrum an Habitaten und Nischen, die wiederum eine hohe Tierdiversität in den Savannensystemen des südlichen Afrikas ermöglichen. Dieses Ökosystem wurde jedoch über Jahrzehnte weltweit durch intensive anthropogene Landnutzung (z.B. Viehwirtschaft) nachhaltig verändert. Dabei wurden die Zusammensetzung, Diversität und Struktur der Vegetation stark verändert. Überweidung in Savannensystemen führt zu einer Degradation des Habitates einhergehend mit dem Verlust von perennierenden Gräsern und krautiger Vegetation. Dies führt zu einem Anstieg an vegetationsfreien Bodenflächen. Beides, sowohl der Verlust an perennierenden Gräsern und krautiger Vegetation sowie der Anstieg an vegetationsfreien Flächen führt zu verbesserten Etablierungsbedingungen für Sträucher (z.B. Rhigozum trichotomum, Acacia mellifera) und auf lange Sicht zu stark verbuschten Flächen. Die Tierdiversität in Savannen ist hiervon entscheidend beeinflusst. Mit sinkender struktureller Diversität verringert sich auch die Tierdiversität. Während der Einfluss von Überweidung auf die Vegetation relativ gut untersucht ist sind Informationen über den Einfluss von Überweidung auf die Tierdiversität, speziell für Reptilien, eher spärlich vorhanden. Zusätzlich ist sehr wenig bekannt zum Einfluss auf die Populationsdynamik (z.B. Verhaltensanpassungen, Raumnutzung, Überlebensrate, Sterberate) einzelner Reptilienarten. Ziel meiner Doktorarbeit ist es den Einfluss von Überweidung durch kommerzielle Farmnutzung auf die Reptiliengemeinschaft und auf verschiedene Aspekte der Populationsdynamik der Echse Pedioplanis lineoocellata lineoocellata zu untersuchen. Hinsichtlich bestimmter Naturschutzmaßnahmen ist es einerseits wichtig zu verstehen welchen Auswirkungen Überweidung auf die gesamte Reptiliengemeinschaft hat. Und zum anderen wie entscheidende Faktoren der Populationsdynamik beeinflusst werden. Beides führt zu einem besseren Verständnis der Reaktion von Reptilien auf Habitatdegradation zu erlangen. Die Ergebnisse meiner Doktorarbeit zeigen eindeutig einen negativen Einfluss der Überweidung und der daraus resultierende Habitatdegradation auf (1) die gesamte Reptiliengemeinschaft und (2) auf einzelne Aspekte der Populationsdynamik von P. lineoocellata. Im Teil 1 wird die signifikante Reduzierung der Reptiliendiversität und Abundanz in degradierten Habitaten beschrieben. Im zweiten Teil wird gezeigt, dass P. lineoocellata das Verhalten an die verschlechterten Lebensbedingungen anpassen kann. Die Art bewegt sich sowohl häufiger als auch über einen längeren Zeitraum und legt dabei größere Distanzen zurück. Zusätzlich vergrößerte die Art ihr Revier (home range) (Teil 3). Im abschließenden Teil wird der negative Einfluss von Überweidung auf die Populationsdynamik von P. lineoocellata beschrieben: In degradierten Habitaten nimmt die Populationsgröße von adulten und juvenilen Echsen ab, die Überlebens- und Geburtenrate sinken, währen zusätzlich das Prädationsrisiko ansteigt. Verantwortlich hierfür ist zum einen die ebenfalls reduzierte Nahrungsverfügbarkeit (Arthropoden) auf degradierten Flächen. Dies hat zur Folge, dass die Populationsgröße abnimmt und die Fitness der Individuen verringert wird, welches sich durch eine Reduzierung der Überlebens- und Geburtenrate bemerkbar macht. Und zum anderen ist es die Reduzierung der Vegetationsbedeckung und der Rückgang an perennierenden Gräsern welche sich negativ auswirken. Als Konsequenz hiervon gehen Nischen und Mikrohabitate verloren und die Möglichkeiten der Reptilien zur Thermoregulation sind verringert. Des Weiteren hat dieser Verlust an perennierender Grasbedeckung auch ein erhöhtes Prädationsrisikos zur Folge. Zusammenfassend lässt sich sagen, dass nicht nur Bäume und Sträucher, wie in anderen Studien gezeigt, eine bedeutende Rolle für die Diversität spielen, sondern auch das perennierende Gras eine wichtige Rolle für die Faunendiversität spielt. Weiterhin zeigte sich, dass Habitatdegradation nicht nur die Population als gesamtes beeinflusst, sondern auch das Verhalten und Populationsparameter einzelner Arten. Des Weiteren ist es Reptilien möglich durch Verhaltensflexibilität auf verschlechterte Umweltbedingen zu reagieren.
In semi-arid savannah ecosystems, the vegetation structure and composition, i.e. the architecture of trees, shrubs, grass tussocks and herbaceous plants, offer a great variety of habitats and niches to sustain animal diversity. In the last decades intensive human land use practises like livestock farming have altered the vegetation in savannah ecosystems worldwide. Extensive grazing leads to a reduction of the perennial and herbaceous vegetation cover, which results in an increased availability of bare soil. Both, the missing competition with perennial grasses and the increase of bare soils favour shrub on open ground and lead to area-wide shrub encroachment. As a consequence of the altered vegetation structure and composition, the structural diversity declines. It has been shown that with decreasing structural diversity animal diversity decline across a variety of taxa. Knowledge on the effects of overgrazing on reptiles, which are an important part of the ecosystem, are missing. Furthermore, the impact of habitat degradation on factors of a species population dynamic and life history, e.g., birth rate, survival rate, predation risk, space requirements or behavioural adaptations are poorly known. Therefore, I investigated the impact of overgrazing on the reptile community in the southern Kalahari. Secondly I analysed population dynamics and the behaviour of the Spotted Sand Lizard, Pedioplanis l. lineoocellata. All four chapters clearly demonstrate that habitat degradation caused by overgrazing had a severe negative impact upon (i) the reptile community as a whole and (ii) on population parameters of Pedioplanis l. lineoocellata. Chapter one showed a significant decline of regional reptile diversity and abundance in degraded habitats. In chapter two I demonstrated that P. lineoocellata moves more frequently, spends more time moving and covers larger distances in degraded than in non-degraded habitats. In addition, home range size of the lizard species increases in degraded habitats as shown by chapter three. Finally, chapter four showed the negative impacts of overgrazing on several population parameters of P. lineoocellata. Absolute population size of adult and juvenile lizards, survival rate and birth rate are significantly lower in degraded habitats. Furthermore, the predation risk was greatly increased in degraded habitats. A combination of a variety of aspects can explain the negative impact of habitat degradation on reptiles. First, reduced prey availability negatively affects survival rate, the birth rate and overall abundance. Second, the loss of perennial plant cover leads to a loss of niches and to a reduction of opportunities to thermoregulate. Furthermore, a loss of cover and is associated with increased predation risk. A major finding of my thesis is that the lizard P. lineoocellata can alter its foraging strategy. Species that are able to adapt and change behaviour, such as P. lineoocellata can effectively buffer against changes in their environment. Furthermore, perennial grass cover can be seen as a crucial ecological component of the vegetation in the semi-arid savannah system of the southern Kalahari. If perennial grass cover is reduced to a certain degree reptile diversity will decline and most other aspects of reptile life history will be negatively influenced. Savannah systems are characterised by a mixture of trees, shrubs and perennial grasses. These three vegetation components determine the composition and structure of the vegetation and accordingly influence the faunal diversity. Trees are viewed as keystone structures and focal points of animal activity for a variety of species. Trees supply animals with shelter, shade and food and act as safe sites, nesting sites, observation posts and foraging sites. Recent research demonstrates a positive influence of shrub patches on animal diversity. Moreover, it would seem that intermediate shrub cover can also sustain viable populations in savannah landscapes as has been demonstrated for small carnivores and rodent species. The influence of perennial grasses on faunal diversity did not receive the same attention as the influence of trees and shrubs. In my thesis I didn’t explicitly measure the direct effects of perennial grasses but my results strongly imply that it has an important role. If the perennial grass cover is significantly depleted my results suggest it will negatively influence reptile diversity and abundance and on several populations parameters of P. lineoocellata. Perennial grass cover is associated with the highest prey abundance, reptile diversity and reptile abundance. It provides reptiles both a refuge from predators and opportunities to optimise thermoregulation. The relevance of each of the three vegetation structural elements is different for each taxa and species. In conclusion, I can all three major vegetation structures in the savannah system are important for faunal diversity.

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Quiroz, IneÌs Arroyo. "Developing countries and the implementation of CITES : a case study of Mexico in the international reptile skin trade." Thesis, University of Kent, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404519.

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Baxter-Gilbert, James H. "The Long Road Ahead: Understanding Road-related Threats to Reptiles and Testing if Current Mitigation Measures are Effective at Minimizing Impacts." Thesis, Laurentian University of Sudbury, 2014. https://zone.biblio.laurentian.ca/dspace/handle/10219/2137.

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Reptile populations are suffering substantial global losses and roads are identified as one of the leading threats to their persistence. Currently, efforts to mitigate this threat are being implemented with various levels of success. I studied the effectiveness of exclusion structures (i.e., fencing) at preventing reptiles from gaining access to the road, and reducing road mortality. I also examined if population connectivity structures (i.e., ecopassages) were effective at reducing habitat and population fragmentation and allowing individuals to access habitats, resources, and mates on both sides of a major road (4 lane highway). I found that the fence was ineffective at preventing reptiles from gaining access to the road; however, reptiles were observed using the ecopassages to cross the road. Behavioural trials testing painted turtles’ (Chrysemys picta) willingness to use an ecopassage demonstrated that refusal was twice more likely than use of an ecopassage. I also examined the potential for roads to pose a physiological threat to roadside populations of reptiles by examining corticosterone (CORT), a stress hormone linked to negative health effects in cases of elevated levels over the long-term. To assess if individuals living near a major road had higher CORT levels than individuals from a less impacted population, I developed a novel means of measuring CORT from painted turtle claws in partnership with Dr. Gabriela Mastromonaco (Toronto Zoo). With long-term CORT levels considered as a proxy for chronic physiological stress, I did not find evidence that populations near roads had altered stress levels. However, this seminal study will provide the framework for further examination of more species, including species-at-risk, and a better understanding of effects of anthropogenic environments on wildlife health. As road ecologists strive to expand our understanding of the threats roads pose to reptiles, it is important that this field spans multiple disciplines, so that we can both understand the direct and indirect threats that roads cause and develop effective mitigation that preserves biodiversity within our anthropogenic landscape.

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Casey, Michelle M. "Quantitative Taphonomy of a Triassic Reptile: Tanytrachelos ahynis from the Cow Branch Formation, Dan River Basin, Solite Quarry, Virginia." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/32503.

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The Virginia Solite Quarry assemblage of Tanytrachelos ahynis, with its exceptionally abundant and uniquely preserved specimens, offers an opportunity to quantify multiple aspects of vertebrate taphonomy. The presence or absence of 128 skeletal elements (i.e., bones) as well as the presence or absence of 136 skeletal variables (i.e., morphometric dimensions) were recorded for 100 specimens collected from two distinct layers within the quarry (lake cycles 2 and 16). Anatomical specimen completeness (or the percent of bones/variables present in a specimen) is low (the median specimen preserves 14.5% of bones and 11.8% of measured variables) in spite of protection from high energy currents, predators, and scavengers afforded by anoxic bottom waters. Specimen size, as approximated by femur length, does not significantly impact specimen completeness. Also, post-exhumation weathering, duration of exposure before burial, and morphotype groupings do not appear to have significantly affected anatomical specimen completeness or articulation. Presence or absence of the enigmatic heterotopic bones represents a true biological signal as indicated by the lack of significant difference in anatomical specimen completeness between the two morphotypes as well as qualitative taphonomic evidence. When anatomical specimen completeness has been corrected for post-depositional faulting, lake cycles 2 and 16 differ from one another significantly in terms of articulation and anatomical completeness of specimens. Specimens with soft-bodied preservation are significantly more articulated, but not significantly more complete, than specimens without preserved soft tissues. Preservation frequency of bones/variables (or the percent of specimens in which a bone/variable is present) varies greatly, but is generally low (an average skeletal element is present in 19% of specimens and an average variable can be measured in 12% of specimens), with significant preferential removal of smaller skeletal elements. Hind limbs, specifically femora, are most commonly preserved. Low anatomical specimen completeness and positive correlation between bone size and frequency of preservation both indicate specimen disturbance by minor hydraulic currents. These taphonomic patterns suggest a moderate-depth depositional environment (slightly shallower than previously proposed).
Master of Science

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Gavira, Rodrigo Samuel Bueno [UNESP]. "Determinantes do aumento metabólico pós-prandial em urutus, Bothrops alternatus (Serpentes, Viperidae)." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/99548.

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Made available in DSpace on 2014-06-11T19:30:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-10-07Bitstream added on 2014-06-13T20:40:03Z : No. of bitstreams: 1 gavira_rsb_me_rcla.pdf: 847914 bytes, checksum: 30801f5783f8efbfaed2c1c9ebf88cd8 (MD5)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
O grupo das serpentes é formado por animais estritamente carnívoros que ingerem suas presas inteiras, sem mastigação. Algumas espécies podem tolerar períodos prolongados de jejum intercalados com ingestão ocasional de presas muito grandes em relação à sua massa corpórea. Tais serpentes apresentam, dentre todos os vertebrados, algumas das mais dramáticas especializações morfológicas, comportamentais e fisiológicas associadas à alimentação. Uma das consequências da ingestão de grandes massas de alimento é o excepcional aumento da taxa metabólica pós-prandial, referido como Ação Dinâmica Específica (ADE). A magnitude dessa resposta metabólica pós-prandial depende essencialmente do tamanho e da natureza do alimento, associado a fatores como o tamanho corpóreo e a temperatura do ambiente. No entanto, raros são os trabalhos que caracterizaram a ADE de espécies de serpentes neotropicais e examinaram os fatores que potencialmente poderiam afetar esta resposta. Deste modo, ao longo dos dois capítulos que compõem a presente dissertação, investiguei alguns dos determinantes proximais do aumento metabólico pós-prandial da urutu-cruzeiro, Bothrops alternatus (Serpentes, Viperidae). O capítulo I foi dedicado à investigação dos efeitos da temperatura e do termoperíodo sobre a ADE de Bothrops alternatus (Serpentes, Viperidae). O capítulo II foi dedicado ao estudo dos efeitos do tamanho da presa sobre a ADE de Bothrops alternatus (Serpentes, Viperidae). Nossos resultados mostraram que o aumento da temperatura corpórea é acompanhado por uma aceleração do processo digestivo às custas de um maior incremento metabólico. A variação destes parâmetros ocorre de maneira inteiramente proporcional de forma que a energética da ADE não foi afetada pela variação da temperatura...
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Rollings, Nicole Anna. "Variation in Telomere Dynamics with Life History Strategy in Polymorphic Reptiles, Ctenophorus pictus and Thamnophis sirtalis parietalis." Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/20926.

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Telomeres, short tandem repeats of TTAGGG at the ends of chromosomes, are dynamic structures which may be affected by the life history strategy of an organism. Telomeres shorten during cellular replication and may also be damaged by reactive oxygen species (ROS). Conversely, they can be lengthened by telomerase activity and ROS may be countered by antioxidant production. Telomere length may affect the repair capacity of tissues and is implicated in the ageing process. Thus telomere dynamics are highly important, vary among species and may vary within species, depending upon life history strategy. Research comparing life histories and telomere dynamics has mostly focussed on inter-species comparisons which may be confounded by genetic variation. By studying the telomeres of polymorphic species with unusual life history strategies we minimise genetic variation and may be able to identify trends that would otherwise be obscured. I investigated the telomere dynamics of two reptile species with unusual life history strategies, painted dragons, Ctenophorus pictus, where males are colour polymorphic, and red-sided garter snakes, Thamnophis sirtalis parietalis, which have strong sexual dimorphism. Painted dragons live for approximately one year in the wild and males vary in their head colour and presence or absence of a yellow gular bib. The morphs vary in life history strategy and behaviours. Red-sided garter snakes hibernate for eight months of the year in communal dens and mate upon emergence in large aggregations of potentially thousands of snakes. The aggregations are heavily male biased, and males highly prioritise reproduction, attempting to court females for up to three weeks while aphagic. By contrast, females invest minimally in mating and prioritise foraging and cellular maintenance. The contrasting behaviours and life history strategies of the individuals within these two species makes them ideal models for intra-species comparisons of telomere dynamics.

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Wilson, Rachel Catharine. "Effects of testosterone on the spatial ecology, coloration, and brain regions in western fence lizards, Sceloporus occidentalis." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1500.

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An organism’s spatial ecology allows for access to essential resources such as food, mates, and escape from predators. Home range size, or the total area an organism inhabits, varies in relation to numerous factors including seasonality. During the breeding season, home range size increases in males across taxa. In addition, males usually also have larger home range sizes than females. This implicates testosterone (T) as a possible mediator of this relationship. Indeed, T causes an increase in home range size of males in numerous species of lizards. In addition to T causing an increase in home range size, it also causes an increase in coloration, which is used as a signal to deter or elicit aggressive behaviors in lizards. Potentially, contests are less common in natural settings than in the lab due to this signaling despite increased frequency overlap of home ranges in males. The larger the home range size of males, mediated through an increase in T, the more overlap with conspecifics. With this increase in spatial demand, or home range size, there is often a corresponding increase in spatially related brain regions. In reptiles, these brain regions are the medial and dorsal cortices (MC and DC respectively). The increase in cortical brain region size due to an increase in spatial demand may be mediated by an increase in neurogenesis. Proliferation of neurons occurs along the ventricles and radiate to numerous regions in the brain including the MC. With respect to the MC, immature neurons, which express the protein doublecortin (DCX), migrate from the ventricles, through the inner plexiform layer and are integrated into the cell layer. Because DCX is only expressed in recently born, migrating neurons, it can be used to measure neurogenesis. In mammals and birds, neurogenesis and growth of certain brain regions is affected by steroid hormones, including T. Here we tested two hypotheses: (1) T affects the home range size of Sceloporus occidentalis and (2) cortical brain region volumes are related to home range size and/or T which is mediated through changes in rates of neurogenesis. We surgically castrated individuals and implanted subjects with either a T-filled implant or blank implant and then released them at their initial capture sites. In addition to these castrated individuals, subjects not subjected to castration served as unmanipulated controls. Home range size of individuals in the field was quantified using a global positioning system (GPS) unit and later delineating those GPS points using minimum convex polygons (MCPs). We predicted that (1) castrated, T-treated lizards and unmanipulated control lizards would have larger home range sizes than castrated, control lizards c and (2) MC and DC cortices would be larger in volume and contain more DCX-immunoreactive cells in the lizards with the highest circulating T levels and with the largest home range sizes. We found that increased T caused an increase in the number of blue abdominal scales. We found no differences in home range size relating to T. Likewise, T did not affect MC volumes. However, we did observe a decrease in DC volume with increasing plasma levels of T. Because T did not affect home range size, it follows that we did not find an effect of T on MC volume. However, the significant result of T causing a decrease in DC volume implies a possible trade off with regards to energetics and the maintenance of brain region volumes as prior research indicates that T in increases energy expenditure and decreases foraging efforts.

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Lickel, Laura Evelyn. "Intake, apparent digestibility, and digesta passage in leopard tortoises (Geochelone pardalis) fed a complete, extruded feed." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/480.

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The influence of feeding juvenile female leopard tortoises (Geochelone pardalis, n=18) a commercially available, complete, extruded feed three (3) or seven days (7) per week on dry matter and digestible energy intake, apparent digestibility of dry matter, organic matter, gross energy and fiber fractions, animal body weight and measurements, digesta transit time, rate of passage, and indigestible fill was evaluated. Both feeding frequencies are commonly practiced with captive tortoises. When fed 7 compared to 3 days per week, dry matter and digestible energy intake was greater. Tortoises gained more g BW, but not when adjusted per kg initial BW. When fed 7 compared to 3 days per week, tortoises grew more in plastron width (PW) and carapace height (CH), but not midline straight carapace length (MSCL), and grew more in calculated shell volume (i.e., a calculated estimate of shell volume using MSCL, PW, and CH), with a higher calculated body condition index (BCI). Providing short fasts (i.e., feeding 3 compared to 7 days per week) may be useful in slowing tortoise growth when animals are provided food ad libitum. In general, ad libitum feeding, especially of a highly digestible extruded feed, is not recommended for captive juvenile G. pardalis, especially when offered food daily. With two data points (detected as outliers) removed due to low fecal output (and resulting unrealistically high apparent digestibility of all nutrients analyzed) of two animals when fed 3 days per week, apparent digestibility of cellulose in tortoises fed 7 (n=18) compared to 3 (n=16) days per week was lower, but no differences were detected in DM, OM, GE, or any other fiber fractions analyzed. Transit time (TT1) was shorter and indigestible fill was higher in tortoises (n=18) fed 7 compared to 3 days per week, regardless of percent Cr marker recovered. With four animals removed due to <50% Cr marker recovery, tortoises fed 7 compared to 3 days per week exhibited shorter mean retention time (RGIT), with no differences in digesta transit or indigestible fill. Longer digesta retention when food availability included short periods of fasting may have allowed tortoises to extract more energy from cellulose.

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Bales, Thomas B. "PROLIFERATION, MIGRATION, AND SURVIVAL OF CELLS IN THE TELENCEPHALON OF THE BALL PYTHON, PYTHON REGIUS." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1271.

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Reptiles exhibit neurogenesis throughout the brain during adulthood. However, very few studies have quantified telencephalon-wide neurogenesis in adulthood, and no studies have performed these investigations in snakes. Quantifying neurogenesis in the adult snake is essential to understanding class-wide adult neurogenesis and providing insight into the evolution of this trait. The thymidine analog 5-bromo-2’-deoxyuridine (BrdU) was used to quantify cell proliferation, migration, and survival in the ball python (Python regius). First, to determine the proper dose of BrdU for injection we subcutaneously injected 50mg/kg, 100mg/kg, and 250mg/kg into 15 adult male P. regius. We found the 250mg/kg dose marked significantly more cells than the 50mg/kg dose, but not the 100mg/kg dose. Then we subcutaneously injected 100mg/kg BrdU into 15 juvenile male P. regius at 3 different time points (2 days, 2 weeks, 2 months) prior to sacrifice to quantify proliferation, migration, and survival of cells in several telencephalic subregions. After sectioning and immunohistochemical staining, we found proliferation to be highest in the accessory olfactory bulb (AoB), retrobulbar regions (AD, AV), dorsal ventricular ridge (DVR), and dorsolateral amygdala/lateral amygdala (DLA/LA). Of the proliferating cells, the proportions of cells that migrated after 2 weeks were highest in the ventral lateral region (VL), anterior medial and lateral cortices (aMC, aLC), and anterior NS (aNS). After 2 months, the highest proportional survival was in the AoB, aLC, aMC, aNS, DVR, and ventral medial regions (VM). Regions involved in long-term functions like spatial memory may require less proliferation and longer survival, while regions involved in short-term functions undergo more proliferation with higher relative attrition.

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Dissertations / Theses on the topic 'Reptile'

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