• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 17
  • 7
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 31
  • 6
  • 5
  • 5
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Comparative morphological and biochemical study of the pineal complex in geckos / thesis presented for the degree of Doctor of Philosophy by Robert Walter Moyer.

Moyer, Robert Walter January 1998 (has links)
Copies of author's previously published articles inserted. / Bibliography: leaves 161-187. / 187, [53] leaves, [54] leaves of plates : ill., maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The pineal complex in gekkotans was examined and compared under the optical and transmission electron microscope in order to elucidate the morphological evidence supporting a role for the pineal organ of these lizards in circadian function. / Thesis (Ph.D.)--University of Adelaide, Dept. of Anatomical Sciences, 1998
12

Auditory nerve fibre activity in the Tokay gecko

Eatock, Ruth Anne January 1978 (has links)
No description available.
13

An ecological study of the lizard fauna of Kaitorete Spit, Canterbury

Freeman, A. B. January 1994 (has links)
Baited pitfall traps were used to sample the lizard fauna at Birdlings Flat on Kaitorete Spit, Canterbury. Four species had been recorded previously from this area; Leiolopisma maccanni Patterson and Daugherty, Leiolopisma nigriplantare polychroma Patterson and Daugherty, Leiolopisma lineoocellatum (Dumeril and Dumeril) and Hoplodactylus maculatus (Gray). Three of these species (L. maccanni, L. n. polychroma and H. maculatus) were captured during the course of the study. The aim of this present study was to examine the nature of the ecological relationship among these three species at Birdlings Flat. Capture data indicated that L. maccanni was almost entirely confined to the dunelands while L. n. polychroma was associated exclusively with shrublands on old dune ridges behind the sand dunes. H. maculatus' distribution encompassed both of these major habitats. Separation on the basis of habitat was thought to be the most important niche variable for these two diurnal skinks. There was some temporal separation in activity of these two species, with L. maccanni active earlier in the day than L. n. polychroma. However, there was a high degree of overlap in the activity periods of these two species. Temporal differentiation between the nocturnal gecko H. maculatus and the two diurnal skinks is thought to be an important means by which these species coexist. The most common prey items consumed by all three species were Diptera, Araneae, C. propinqua seeds, Hemiptera, unidentified arthropod eggs, Coleoptera and Hymenoptera. Dietary differences between the two skink species were apparent although these differences appeared to be related to the preferred habitats of the respective species. Density estimates for L. maccanni varied between 1050/ha and 1850/ha while L. n. polychroma density varied between 200/ha and 400/ha. The density of H. maculatus was not calculated but appeared to be intermediate to the density of the two skink species. The apparent disappearance of L. lineoocellatum from an area where they were once relatively common is cause for concern. There is no obvious reason for this decline although it may be related to the combined impacts of predation, collection and habitat disturbance.
14

Nanoscale adhesion of individual gecko spatulae explored by atomic force microscopy

Huber, Gerrit. January 2006 (has links)
Zugl.: Stuttgart, Univ., Diss., 2005.
15

Spatial and Temporal Patterns of Diversification in Leaf-toed Geckos (Phyllodactylidae: Phyllodactylus) throughout the Mexican Dry Forest

Blair, Christopher 10 December 2012 (has links)
Understanding the ecological and evolutionary processes responsible for shaping patterns of genetic variation in natural populations is a long-standing goal in molecular ecology. Although an extensive number of recent studies focus on patterns and processes throughout tropical rain forest ecosystems, substantially less effort has been placed on tropical dry forests (TDFs); a habitat known to harbour a large percentage of Earth’s diversity. In this thesis I use leaf-toed geckos of the genus Phyllodactylus to understand both the historical and contemporary processes influencing diversification throughout Mexico’s TDFs. In Chapter 2 I isolate and characterize microsatellite markers for the gecko P. tuberculosus. Chapter 3 uses these loci to conduct a landscape genetic analysis of the species near Alamos, Sonora. I find that the inclusion of landscape variables explains more genetic variance versus Euclidean distance alone. Chapter 4 examines the evolutionary history of the P. tuberculosus group throughout western Mexico. Results suggest that habitat and climate shifts during the Miocene and Pleistocene were important divers of diversification. Chapter 5 uses microsatellite and mtDNA markers to compare historical and contemporary demographic parameters in P. tuberculosus. I find evidence for low historical gene flow and high female philopatry, recent reductions in population sizes, and higher correlations between landscape and contemporary gene flow versus historical gene flow and mtDNA divergence. In Chapter 6 I examine the biogeographic and taxonomic consequences of the dynamic history of Baja California. My phylogenetic results provide evidence for a trans-peninsular seaway in the Isthmus of La Paz region and suggests that P. xanti nocticolus warrants species status. My results also suggest the possibility of a seaway near the Loreto area that needs to be evaluated further. By combining multiple molecular marker-types and analytical methods, this thesis adds to our understanding of diversification processes throughout the threatened Mexican TDF.
16

Spatial and Temporal Patterns of Diversification in Leaf-toed Geckos (Phyllodactylidae: Phyllodactylus) throughout the Mexican Dry Forest

Blair, Christopher 10 December 2012 (has links)
Understanding the ecological and evolutionary processes responsible for shaping patterns of genetic variation in natural populations is a long-standing goal in molecular ecology. Although an extensive number of recent studies focus on patterns and processes throughout tropical rain forest ecosystems, substantially less effort has been placed on tropical dry forests (TDFs); a habitat known to harbour a large percentage of Earth’s diversity. In this thesis I use leaf-toed geckos of the genus Phyllodactylus to understand both the historical and contemporary processes influencing diversification throughout Mexico’s TDFs. In Chapter 2 I isolate and characterize microsatellite markers for the gecko P. tuberculosus. Chapter 3 uses these loci to conduct a landscape genetic analysis of the species near Alamos, Sonora. I find that the inclusion of landscape variables explains more genetic variance versus Euclidean distance alone. Chapter 4 examines the evolutionary history of the P. tuberculosus group throughout western Mexico. Results suggest that habitat and climate shifts during the Miocene and Pleistocene were important divers of diversification. Chapter 5 uses microsatellite and mtDNA markers to compare historical and contemporary demographic parameters in P. tuberculosus. I find evidence for low historical gene flow and high female philopatry, recent reductions in population sizes, and higher correlations between landscape and contemporary gene flow versus historical gene flow and mtDNA divergence. In Chapter 6 I examine the biogeographic and taxonomic consequences of the dynamic history of Baja California. My phylogenetic results provide evidence for a trans-peninsular seaway in the Isthmus of La Paz region and suggests that P. xanti nocticolus warrants species status. My results also suggest the possibility of a seaway near the Loreto area that needs to be evaluated further. By combining multiple molecular marker-types and analytical methods, this thesis adds to our understanding of diversification processes throughout the threatened Mexican TDF.
17

Testování vlivu hybridizace na fitness u gekončíků rodu Eublepharis pomocí performančních testů / Evaluation of hybridization effect on fitness of eyelid geckos (Eublepharis, Gekkota) by performance tests

Kohoutová, Tereza January 2021 (has links)
An interspecies hybridization is usually viewed from two sides - either as mistakes in a reproduction resulting in decrease of a hybrids fitness (e. g. loss or decrease of viability and fertility) or as a mechanism helping animals adaptively respond to environmental changes resulting in higher fitness. Fitness is usually represented as a set of correlates. One of the correlates is an organism performance which is represented by a set of maximal values from measured physical activities. This thesis focuses on the evaluation of the endurance and the bite force for gecko species E. macularius and E. angramayniu, their interspecies hybrids and intraspecies hybrids to determine their performance. The results show differences in the bite force among each of the tested groups. E. macularius has the lowest bite force, while the highest bite force was measured in E. angramayniu. The bite force of interspecies hybrids is intermediate in comparison to the parent species. Nevertheless, intraspecies hybrids of large form and white form of E. macularius exceeds their parents in measured bite force. The variability in bite force suggests a positive effect of hybridization on fitness. The bite force differences between the large form and the white form of E. macularius support the hypothesis that there exist more...
18

Vliv maternálních efektů na evoluci velikosti gekonů / Influence of maternal effect on body size evolution in geckos

Kubát, Jan January 2015 (has links)
In this diploma thesis has been tested potential of maternal influences on body growth at two model groups of geckos with large interspecific body size variability. The effect of egg manipulation to hatchling size was proved to be significant for hatchlings at both model species Paroedura picta and Goniurosaurus lichtenfelderi. However, in adult animals, there were no more significant body size differences caused by egg manipulation. It leads to conclusion that both species of geckos have compensatory growth and its adult size is likely to be primarily genetically determined. Key words: maternal effect, egg manipulation, body growth, allometric engeneering, Paroedura picta, Goniurosaurus lichtenfelderi
19

Evoluční a vývojové aspekty dentice šupinatých plazů / Evolutionary and developmental aspects of dentition of squamate reptiles

Zahradníček, Oldřich January 2011 (has links)
EVOLUTIONARY AND DEVELOPMENTAL ASPECTS OF DENTITION OF SQUAMATE REPTILES Summary of the PhD. thesis Dentition and its evolutionary modifications played important roles during the radiation of reptiles. It is generally accepted that a plesiomorphic state for reptiles is represented by homodont, polyphyodont dentition with conical or cylindroconical teeth. However, in contrast to mammalian dentition which is the object of intensive research, reptilian dentition is studied only rarely. I therefore focused on developmental and evolutionary aspects of squamate dentition and used histological, immunohistochemical and in situ hybridization methods, computerised tomography, rentgenography and scanning electron microskopy. The goals of this work were as following: (a) to choose the model taxa representing squamate lineages relevant from a phylogenetic position as well as possessing dissimilar types of dental adaptations; (b) to evaluate using of these taxa as model species; (c) in these taxa describe basic odontogenic features. As a species with generalized dentition gecko Paroedura picta was chosen, the up coming reptilian model species with features also present in a wide spectrum of other lizards. I focused mainly on the developmental differences between teeth of the null and functional generations, development...
20

Phylogeny And Biogeography Of Hemidactylus Oken, 1817 Geckos Of The Indian Subcontinent

Bansal, Rohini 07 1900 (has links) (PDF)
Geckos of the genus Hemidactylus Oken, 1817 are one of the most widely distributed and species-rich groups of gekkonids. With approximately 90 species, the genus Hemidactylus accounts for 10% of the total number of species in the family Gekkonidae (Carranza and Arnold, 2006). They are found in a range of ecological conditions from wet tropical forest to arid deserts. Their wide distribution is believed to have been facilitated not only naturally, but also through human mediated transport. Indian subcontinent houses 31 species of these geckos, 23 of which are endemic to the subcontinent. The aim of this study was to understand the phylogeny and biogeography of Hemidactylus geckos of the Indian subcontinent. In order to arrive at the conclusions regarding the biogeographic history of this widely distributed taxon on the Indian subcontinent, an integrative approach was followed. First the phylogenetic reconstruction of Indian species was undertaken. The ancestral areas of distribution were reconstructed on the phylogeny and the divergence dates of the species were also estimated. Finally, the biogeographic events were inferred in accordance with the geological events with respect to the divergent times for these radiations. Results indicated that Hemidactylus geckos of the Indian subcontinent belong to three geographical clades: Southeast Asian clade, West-Asian arid clade and a ‘unique Indian radiation’ which consisted majority of the species distributed in India that are largely confined to the Indian subcontinent. Additionally, the three widely distributed, commensal species (H. brookii, H. frenatus and H. flaviviridis) were nested within the Indian radiation suggesting their Indian origin. It was also seen that the endemic Hemidactylus geckos of Sri Lanka have been derived from India through multiple independent dispersal events spread across the Oligocene-Miocene. These dispersals were both geo dispersal as well as transmarine dispersal events. However, the species distributed both in India and Sri Lanka appear to have undergone recent dispersals into Sri Lanka and probably back into India, primarily through human agency. Thus, it was inferred that the Indian subcontinent has served as an important arena for diversification among the Hemidactylus geckos and their spread. In addition, it was discovered that H. anamallensis, a species endemic to Southern Western Ghats of peninsular India was probably genetically distinct from Hemidactylus, indicating that it could not be Hemidactylus at all. Thus, the phylogenetic position of H. anamallensis within the subfamily Gekkoninae was also investigated and its genetic distinctiveness from that of Hemidactylus was also tested. Results showed that H. anamallensis lineage was indeed distinct from Hemidactylus group, as well as from other closely related genera (Cyrtodactylus and Geckoella) in both nuclear and mitochondrial markers. Divergence estimates supported a scenario wherein H. anamallensis dispersed across marine barrier to the drifting peninsular Indian plate in the late Cretaceous, whereas Hemidactylus arrived on the peninsular India after the Indian plate collided with the Eurasian plate. Based on these molecular evidence and biogeographical scenario it was proposed that genus Dravidogecko should be resurrected.

Page generated in 0.028 seconds