1,472 research outputs found
Reproduction and sexual dimorphism in the montane viviparous lizard, Pseudocordylus capensis (Sauria: Cordylidae)
Pseudocordylus capensis, a melanistic lizard, is regarded as a basal species in the phylogeny of the family Cordylidae and is endemic to the Cape Fold Mountains. Data for this study were obtained from measurements and dissections of museum specimens (N = 68). Sexual maturity in both sexes is attained at around 80-90 mm snout-vent length (SVL). Body sizes (SVL) differed significantly between sexes, the mean SVL of adult males being 92.3 mm (range 78.4−104.2) and that of adult females 95.9 mm (range 83.1-108.5). Although the rate of increase in head measurements did not differ significantly between sexes, analysis of covariance (ancova) indicated that head dimensions are marginally, but significantly, larger in males than in females of equivalent SVL. The slight female-plus dimorphism in SVL and male-plus dimorphism in head dimensions is suggested to be related to life in the cold montane environment, and to differential growth to increase female reproductive fitness, rather than to be the result of sexual selection. Males exhibit testicular recrudescence during autumn, with full spermiogenesis during winter maintained through spring (October). The testicular cycle shows characteristics of both ‘post-nuptial’ and ‘pre-nuptial’ cycles previously described in Cordylidae lizards. Small testicular volume, associated with testicular regression, was recorded during summer (November/December). Spermatozoa were present in the epididymis from May through to October. In synchrony with the spermatogenic cycle, the onset of vitellogenesis in females starts in autumn, culminating in ovulation during spring (September-October). Females are gravid during summer and give birth to 2-3 young in late summer (December-January). The timing of events during the reproductive cycle of females corresponds to the autumn cycles reported for all other female Cordylidae lizards studied to date, therefore pointing to strong conservatism regarding the timing of female reproductive cycles in this lizard family. Fatbody size in individuals of both sexes is largest during late summer and autumn, and progressively declines during winter to reach smallest sizes during the summer months. The fact that this phylogenetically basal species exhibits well-synchronised male and female autumn gonadal cycles adds to the data that suggest these reproductive traits evolved during the early divergence from the Cordyliformes ancestor and that the evolution of viviparity may be linked to this event or followed soon after
Cordylus Minor: A valid species of South african lizard (Reptilia: Cordylidae)
The taxonomic status of Cordylus cordylus minor FitzSimons 1943 is reconsidered. An analysis of variation in external morphological characters shows minor and cordylus to be two non-overlapping sets of organisms. A phylogenetic study shows the minor-cordylus set to be non-monophyletic, leaving no option than to consider minor a separate species
Taxonomic status of the melanistic forms of the Cordylus cordylus complex (Reptilia: Cordylidae) in the south-western Cape, South Africa
The taxonomic status of the two melanistic morphotypes belonging to the Cordylus cordylus complex in the south-western Cape, South Africa, is considered. It is proposed that the coastal melanistic form, previously described as subspecies of C. cordylus,be considered a separate species, while the previously unknown montane melanistic form is also described as a new species. Areas of uncertainty, which may affect the status of the two melanistic species in the future, are discussed
Francois Jacobus van Zyl, hoogleraar 1960-1978
Francois Jacobus van Zyl, professor 1960-1978Professor Francois Jacobus van Zyl (6th May 1913-) served as head of the Department of Science of Religion and Missiology, Faculty of Theology (Sec A),University of Pretoria, during the period 1960-1978. This article (compiled from two previously published articles) contains a short biography, a discussion of hisviews on theology, Science of Religion, Philosophy of Religion, and Missiology. He is portrayed as a theologian with Barthian convictions. He worked from a broad theological base which can be described as ‘theology of the Word’. His primary audience was the Nederduitsch Hervormde Kerk and his theological activities(especially in the period 1960-1983) must be seen in relation to his influential role in the same church
Trauma, resilience and vulnerability to PTSD : a review and clinical case analysis
This article begins with two case examples of a girl and an adolescent who were raped and developed chronic PTSD. These are used as a basis for understanding the role of a range of factors that are associated with resilience and vulnerability in the face of traumatic events. A literature review examines the proportion of individuals who develop PTSD following trauma and the factors associated with vulnerability and resilience. These include gender, developmental factors, social support and personality factors. Psychological factors associated with maintenance of chronic PTSD are also briefly reviewed. This material is used as a basis for reconsidering the case examples. Each case is formulated within a framework based on sources of vulnerability and qualities of resilience. Approaches to intervention are suggested that could address the range of factors making the individuals vulnerable to chronic psychological problems and support resiliency and recovery
Chenin blanc Wine Volatiles and the Intensity of a Guava-like Flavour
A guava-like flavour occurring in some South African Chenin blanc and Colombard dry white wines was investigated. Headspace volatiles of some of these wines, as well as those of fresh guava fruits, were analysed by means of a gas chromatograph equipped with a "sniffer-detector". In contrast to the headspace concentrate of guava fruits, no single fraction with a typical guava flavour was found in the wines analysed. The pattern recognition system "ARTHUR" was therefore used to investigate relationships between the more important wine volatiles and the intensity of a guava-like flavour of a set of wines originating from the same Chenin blanc must. Sensory scores for this flavour were used in both category and continuous property analysis in each case. Category and correlation to property plots were used to elucidate the results. Several promising variables and ratios between variables were singled out for further investigation, notably ethyl butyrate and the ratios ethyl butyrate/ethyl decanoate and ethyl butyrate/ethyl octanoate
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