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Variation in chelonian reproductive patterns is well documented. Previous studies of loggerhead musk turtles (Sternotherus minor) reproduction have not attempted to control for variation in latitude, local population differences, and seasonal variation. The present study attempts to control for these variables by collecting turtles from one population for one reproductive season. The reproductive pattern of S. minor at the southern limit of its range (Central Florida) is compared to those of S. minor studied elsewhere. Both male and female musk turtles mature after five to six years and at approximately 60mm plastron length. No sexual dimorphism in overall body size is evident. There is a significant relationship between testis mass and male body size. Spermatogenesis begins in June as testes begin to enlarge. A peak in the testicular cycle is observed in August and September followed by testicular regression from October through January. A germinal quiescent phase is evident from February through April. Vitellogenesis in females begins in mid-September and the first clutch is laid in late October. Ovipositions continue until mid-June when follicular regression begins. A brief but distinct ovarian quiescent period occurs in August. Mean clutch size is 3.0 (range= 1-5). Clutch size and clutch mass were significantly correlated with body size. Egg length is not significantly correlated with clutch size or plastron length. Four clutches per year are common and some females probably produce five. Reproductive potential and individual reproductive effort are both correlated with body size. Testicular activity peaks six months after a peak in the ovarian cycle. Similarities with other studies of Sternotherus minor include: timing of the reproductive cycles, mean female size, and size and age at maturity. Mean clutch size in Central Florida is significantly larger than elsewhere. This difference is explained by the fact that more females produce three and four eggs. While similarities and differences in reproductive characteristics do exist between Central Florida S. minor and more northern populations, it is clear that those similarities and differences must be interpreted with respect to the methods of data collection used. Annual reproductive potential is enhanced in the Central Florida population. This is explained by greater resource availability which is translated into a greater reproductive output.

No description available.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 3 May 2018. / The movement ecology of a species can dictate their survival and success. Animals are motivated to move depending on resource priorities and in turn their movements are influenced by the surrounding environment. Natural habitats are being increasingly disturbed by anthropogenic changes which often creates several implications for the existing wildlife. One of these changes include extensive road networks that may fragment landscapes and increase mortality risks for local fauna. This current and global issue is often researched with the aid of road kill statistics which can create a biased view. My study highlights a more realistic method for understanding how organisms interpret and react to road infrastructure by using the movement patterns of 109 telemetered Puff Adders (Bitis arietans). To assess the effect of roads on these snakes within Dinokeng Game Reserve (Gauteng, South Africa) over eight years, Puff Adder lie-up locations (to the nearest road) and movement paths were analysed. Sex, season, years, and the types of roads within the reserve were included to evaluate the motivation for movement and if roads were inhibiting or aiding movement patterns. Compared to random, Puff Adders were closer too, and crossed roads more often. Males crossed roads more frequently than females and during non-mating season, both sexes were closer to roads. Narrow roads with low levels of traffic were also crossed more often. Overall, the roads in Dinokeng Game Reserve do not inhibit movement and patterns suggest that roads may be advantageous for Puff Adders. Roads appear to be foraging hotspots because of micro habitats created along the verges. However, these positive attributes could result in a potential risk when road usage is intensified by traffic. Understanding how species interact with changes to their environment is essential for appropriate management and mitigation and this study illustrates the necessity for unbiased research to properly evaluate these changes and reactions. / EM2018

Student Number : 0316126G - MSc dissertation - School of Animal, Plant and Environmental Sciences - Faculty of Science / I investigated whether inorganic contaminants associated with gold mining waste discharges in the Free State Province, South Africa, were accumulated by a threatened species of lizard, Cordylus giganteus; if the route of exposure could be dietary, and whether accumulation of contaminants could be associated with potential physiological costs. I compared elemental concentrations in tissue and blood samples between populations of this species, from four sites around the province. Inorganic contaminants were known to be elevated in soils, water, sediments and vegetation of the first mining site, and to a lesser extent at the second mining site. The third site was not known to be contaminated by mining discharges, but was selected because of its potential to be contaminated by wind-blown contaminants. This site was also heavily overgrazed. The fourth site was both uncontaminated by mining and relatively undisturbed. Lizards from the most contaminated site had significantly higher blood concentrations of Li, Na, Al, S, Ca, P, Si, Cr, Mn, Fe, Ni, W and Bi when compared with all the other sites investigated. Based upon a comparison of elemental concentrations in selected lizard prey items found at these sites (Coleoptera, Tenebrionidae) I did not find conclusive evidence for a dietary route of exposure to contaminants. I tested for significant differences in body condition among populations. Lizards from the heavily grazed site were in similar condition to lizards from the most contaminated site, and all these lizards were in significantly poorer condition than lizards from the undisturbed site. The adult sex ratio of the population inhabiting the most contaminated site also deviated significantly from an expected 1:1 ratio in favour of females. The reason for this deviation is not understood, but may be a consequence of sexes being differentially affected by inorganic contaminants. My research demonstrates that the disposal of gold and uranium mine waste has resulted in the accumulation of contaminants by a representative resident vertebrate, and that this accumulation is potentially associated with poorer body condition which might affect fitness. It highlights the potential threat of mining-waste discharges to lizards, shows the need for site remediation measures, and also highlights the need for further investigation into the potential effects of environmental contaminants from gold and uranium mine waste on exposed vertebrates in South Africa.

The genus Kannemeyeria is one of the most important and distinctive taxa of the Triassic dicynodonts. It became the first Triassic dicynodont known to science, and thus forms the benchmark for the comparison of the evolution and morphology of other Triassic dicynodonts. An understanding of this genus forms an integral part of the biozonation of the Beaufort Group, and is pivotal in influencing the interpretation of the evolution, physiology and phylogenetic relationships of the Triassic dicynodonts. This study focuses on the detailed cranial morphology and relationships of the Kannemeyeria, and uses a rigorous morphological investigation as the basis for a meaningful elucidation of the functional and thus physiological aspects of this dicynodont. The descriptions demonstrate that variations related to the skull size, distortion or naturally occurring variation within the genus allow for the synonymy of the formerly recognised species K. latifrons Broom (1898; 1913), K. erithrea Haughton (1915) and K. wilsoni Broom (1937). This conclusion is further supported by the allometric analysis which cannot distinguish the variation observed in the holotypes with that occurring naturally within a growth series. Apart from the large specimen, the other smaller individuals are accommodated in the genus as different ontogenetic stages of the growth series represented by K. simocephalus Weithofer (1888). Several allometric variables show unusual patterns of development, indicating that Kannemeyeria can be subdivided into ontological classes, as juvenile and adult forms, separated from each other by a particular level of development. An age-related threshold level is suggested, and considered to represent an animal reaching sexual maturity. It is consequently proposed that the Kannemeyeria population was, at an age-related level, subdivided into sexually mature and immature groups but remained ecologically homogeneous. Both the descriptions and the allometric analysis of the species K. cristarhynchus Keyser & Cruickshank (1979) clearly indicate that it does not conform to the growth series of K. simocephalus and thus the differences observed between these two taxa are not constrained to size increases. Consequently, the recognition of the species K. cristarhynchus is considered valid. From the observations of the cranial morphology, tested using an allometric analysis, generic and specific diagnoses are constructed for Kannemeyeria and its two African species. Several features of Kannemeyeria are discussed in a functional context. A corrugated hom-covered snout and large caniniform processes are considered to be associated with defence and posturing behaviour. Several features of the braincase also suggest herding behaviour. Kannemeyeria also has a slightly different occipital musculature arrangement than that proposed for many other dicynodonts. Most Kannemeyeria cranial features are related to its masticatory function. From the analysis of masticatory cycle it is clear that the jaw action is described via a single pivot-point, which in Kannemeyeria approached the original, primitive position of the jaw hinge. The vertical orientation of the articulation and this pivot-point ensured that the muscle action during second phase of mastication produced an upward crushing and grinding action instead of the typical fore-and-aft motion of many other dicynodonts. It also meant that the muscle force was at their maximum, and little or no energy was lost to translation of the moment arm at the jaw articulation. Consequently, the Kannemeyeria masticatory cycle was both highly effective and extremely efficient. The morphology, and resultant physiology, of Kannemeyeria skull is considered to represent the innovative foundation for much of the success of many of the later Triassic dicynodonts.

A herpetofauna do Cerrado foi investigada ao longo de extensa área da bacia do rio Tocantins de três formas distintas e complementares. Primeiro, uma amostragem rápida realizada em 11 áreas situadas entre o Planalto Central em Goiás e o norte da depressão do Tocantins na divisa dos estados de Tocantins e Maranhão obteve dados menos completos, porém em toda a extensão estudada. Segundo, na parte central da área a UHE LEM, foi intensamente amostrada, obtendo-se uma lista completa de espécies para a área e dados sobre sua distribuição na paisagem. As informações reunidas também permitiram identificar alguns dos impactos causados pelo empreendimento. Terceiro, nesta área, seis pontos foram amostrados bimestralmente ao longo de três anos, permitindo obter informações mais finas sobre o efeito do habitat, da sazonalidade e do deslocamento da fauna pelo enchimento do reservatório nas assembléias de anuros e lagartos. Os dendrogramas construídos com índices de similaridade de Jaccard entre áreas do Cerrado e de outras paisagens neotropicais adjacentes relativamente bem amostradas indica que a fauna de serpentes, lagartos e anuros do Cerrado forma um grupo em relação outras paisagens, subdivido em dois grupos. Um deles está asssociado às depressões de baixa altitude, o outro aos planaltos centrais ou meridionais. No norte do Cerrado a riqueza de espécies é maior, ocorrendo espécies compartilhadas com a Amazônia ou com a Caatinga. No sul, ocorrem espécies com distribuição meridional. O número de espécies geralmente aumenta das áreas meridionais mais áridas para as áreas mais chuvosas próximas ao Equador. Os grupos aquáticos, fossoriais e arborícolas são especialmente mais diversos nas áreas equatoriais. O Cerrado da Depressão do Tocantins é, após as áreas Amazônicas, geralmente a área mais rica em espécies. Lagartos de alta temperatura corporal são mais freqüentes nos cerrados abertos situados nos interflúvios; espécies mais sensíveis a desidratação e de menor temperatura corporal ocorrem nas florestas de fundo de vale. No baixo curso dos rios, nas planícies aluviais e terraços registraram-se abundâncias elevadas de anuros de reprodução aquática, que usam habitats abertos ou florestados. Nas áreas de relevo mais encaixado das cabeceiras estes espécies são menos freqüentes. Os lagartos são menos afetados pelas sazonalidade climática que os anuros. Na estação chuvosa, especialmente em dezembro, ocorreram picos de freqüência de ocorrência, de atividade e maior riqueza de anuros. A reprodução e os nascimentos ocorrem concentrados na estação chuvosa na maioria das espécies, mas esta é especialmente mais concentrada nesta época nos anuros. A diferenciação filogenética dos nichos termo-hídricos das espécies de anuros e lagartos nas assembléias permite a partilha de recursos no tempo e no espaço. Os nichos termo-hídricos das espécies variam entre espécies com maior temperatura corporal e resistência elevada à desidratação e espécies com menor temperatura corporal e baixa resistência a desidratação. A organização espaço temporal das assembléias é fortemente influenciada pela distribuição dos recursos termo-hídricos (microhabitats e microclimas) e pelos fatores que determinam esta distribuição: as interações entre perfis topográficos, o embasamento geológico e a sazonalidade climática. A temperatura e a pluviosidade determinam a organização das assembléias e a distribuição geográfica das espécies. As variações históricas da temperatura podem influenciar a diferenciação das espécies tanto quanto as variações de pluviosidade. O enchimento do reservatório causou a perda de populações de muitas espécies, mas os efeitos foram especialmente graves sobre as espécies de distribuição restrita ou que ocorriam em densidades elevadas em ambientes exclusivos da área inundada. Também houve fragmentação de habitats e alteração dos regimes fluviais a jusante, afetando os habitats inundáveis a jusante. O represamento também impede o transporte de animais em balsas de vegetação pelo rio, interrompendo o provável fluxo gênico entre as margens e rio abaixo. Nas comunidades da margem do reservatório o efeito principal do enchimento foi um aumento extraordinário da freqüência de Chaunus gr. granulosus e Physalaemus centralis nos meses de dezembro. No cerrado, o aumento das freqüências de várias espécies de anuros, principalmente Chaunus gr. granulosus ocorreu logo após o inicio do enchimento. Na floresta o grande aumento de freqüência de Physalaemus centralis ocorreu na próxima estação chuvosa, quando houve também uma redução dos lagartos. Nos estudos de impacto ambiental realizados em 1998 uma parcela pequena da diversidade foi registrada. Um esforço muito maior é necessário para diagnosticar os impactos de um empreendimento do porte da UHE LEM. O estudo dos impactos ambientais é fundamental para permitir desenvolver procedimentos menos prejudiciais ao meio ambiente, mas também é uma estratégia para investigar como as condições ambientais influenciam a organização das comunidades biológicas. / The Cerrado herpetofauna was studied along the basin of the Tocantins river using three distinct and complementary approaches. First, a fast sampling scheme, covering all the studied area, was conducted in 11 sites between the Central Plateau, in the state of Goiás, and the northern portion of the Tocantins depression, at the border of the states of Tocantins and Maranhão. Second, the central portion of the studied area, the UHE LEM, was intensively sampled, resulting in a complete list of species for this area and data about their distribution in the landscape in a way that allowed the identification of some of the impacts caused by the construction of the dam. Third, six sites were sampled in two months intervals during three years, providing accurate information about the effects of habitat, seasonality, and of the movement of the fauna in response to the filling of the lake on the anuran and lizard assemblages. The comparisons among Cerrado sites and sites in other adjacent Neotropical landscapes that have been relatively well sampled, based on Jaccard similarity indices, indicate that the Cerrado snakes, lizards and anurans constitute a distinct group relative to the other landscapes. The Cerrado group can be further subdivided in two groups: one associated to the depressions in low altitude, and the other associated to the central or southern plateaus. In northern Cerrado, species richness is greater, and some species are shared with Amazonia or with Caatinga. The number of species generally increases from the more arid, southern areas to the more humid areas close to the Equator. The aquatic, fossorial, and arboreal groups are specially more diverse in the Equatorial areas. The Cerrado of the Tocantins Depression is, after the Amazonian areas, the area with larger species richness. Lizards with high body temperature are more common in the open cerrados located in the interfluvia; species that are more susceptible to dehydration and with lower body temperature occur in the forests at the bottom of the valleys. In the lower portion of the rivers, at the alluvial plains and terraces, there was a high abundance of anurans with aquatic reproduction, occurring in open or forested habitats. In the headwater regions, were the relief is more steep, these species are less common. Lizards are less affected by climatic seasonality than anurans. In the rainy season, specially in December, there were peaks in the frequency of occurrence, activity and richness of anurans. Reproduction is concentrated in the rainy season for most species, but specially for the anurans. The phylogenetic differentiation of the thermo-hydric 329 niches of the anuran and lizard species in the assemblages allows for the partitioning of the resources in time and space. The thermo-hydric niches vary between species with larger body temperature and less susceptibility to dehydration, and species with smaller body temperature, and more prone to dehydration. The spatial and temporal organization of the assemblages is highly influenced by the distribution of the thermohydric resources (microhabitats and microclimates) and by the factors that determine this distribution: the interactions among topography, geology, and seasonality. Temperature and pluviosity determine the organization of the assemblages and the geographic distribution of the species. Historical variations in both temperature and pluviosity may influence the differentiation of species. The filling of the lake caused the loss of populations of many species, but the effects were specially important on species with restricted distributions or that occurred in high densities in habitats that were exclusive of the flooded area. There was also fragmentation of habitats and alterations in the fluvial regimen upriver, affecting the seasonally flooded habitats in this region. The lake also restricts the movement of animals on top of vegetation fragments that are carried by the river, interrupting a possible gene flow between the opposite margins and to the regions downriver. In the communities at the margins of the lake, the main effect of the lake formation was a high increase in the frequency of Chaunus gr. granulosus and Physalaemus centralis in the month of December. In the cerrado, the increase in frequency of several anuran species, mainly Chaunus gr. granulosus, occurred closely after the formation of the lake. In the forest, the high increase in frequency of Physalaemus centralis happened in the next rainy season, when a reduction in the frequency of lizards was also observed. In the Environmental Impact studies conducted in 1998, a small portion of the diversity was recorded. A larger effort is necessary to diagnose the impacts of such a large dam as was UHE LEM. The study of environmental impacts is of fundamental importance to allow the development of techniques that cause less harm to the environment, but is also a strategy to investigate how the environmental conditions influence the organization of biological communities.

Thesis (Ph. D.)--University of Chicago, Dept. of Organismal Biology and Anatomy, June 2001. / Includes bibliographical references. Also available on the Internet.