Browsing by Author "Rautenbach, Ignatius Lourens."

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Infraspecific systematics of the yellow mongoose Cynictis penicillata.
(1990) Taylor, Peter John.; Meester, Jurgens Anthonie Jansen.; Rautenbach, Ignatius Lourens.
Geographic variation was analysed in morphological (colour, morphometric) and genetic (electrophoretic, chromosomal) characters in the yellow mongoose cynictis penicillata, a diurnal, colonial, burrow-dwelling viverrid, endemic to and widespread throughout Southern Africa. The causal bases of observed geographic patterns were investigated, and a taxonomic revision of the species was undertaken. Three physical properties of pelage colour (hue, value and chroma) were measured independently using Munsell colour charts and a tristimulus colorimeter. Hue and chroma varied from yellowish (hue) and bleached (chroma) in the north to a brighter, (chroma) tawny-orange (hue) in the south. A zone of rapid colour change separated northern and southern groups. Specimens from the drier western areas were paler (in value) than specimens from more easterly localities. Colour patterns were interpreted in terms in the principle of metachromism. Environmental correlates of colour were analysed. Non-geographic (age, sex, individual) and geographic variation was analysed in 14 cranial and two external characters, using multivariate and univariate techniques. The species does not show secondary sexual dimorphism. Multivariate analyses resulted in the description of four parapatric subspecies, three of which were distinguished on the basis of skull size (which accounted for 93% of geographic variation). Subspecies were separated by continuous zones of craniometric differentiation (transition zones). Craniometric overlap (intergradation) occurred across transition zones. The geographic pattern of craniometric variation in C. penicillata could be explained by either an allopatric or a parapatric mode of speciation. A cladistic analysis of coded cranial characters was used to infer the historical pattern of range expansion in the species. The population genetical structure, based on electrophoretic analysis of 28 loci in eight populations of yellow mongooses, was characterised by the absence of genetic divergence between morphometrically-defined subspecies, a mean expected heterozygosity of 3.4%, low genetic distances between populations (0.000--0.105 for Nei's genetic distance), and a surprisingly high fixation index (FST) of 0.585. The basic karyotype of the yellow mongoose was invariant geographically (2n = 36, NF = 72), although a single, supernumerary microchromosome was detected in four out of the five populations sampled. G- and C-banded karyotypes are presented. Evolutionary relationships among eight Southern African viverrid species, including the yellow mongoose, were inferred from phenetic and cladistic analyses of allelic variation at 18 protein loci. These data suggested the separate evolution of social and solitary lineages of mongooses.
The mammals of the Transvaal.
(1978) Rautenbach, Ignatius Lourens.; Meester, Jurgens Anthonie Jansen.
The primary object of this study is to provide a checklist of the mammals occurring within the Transvaal. A general biological account of each species forms the bulk of this treatise, - discussing, in order of sequence, firstly the taxonomic status of each species as based on a study of available museum specimens. Thereafter the distribution of each species is discussed, and illustrated with a map of known distribution. Remarks are presented on the various environmental factors that may influence individual species ranges. Habitat preferences, habits, and food preferences are then discussed. Available data on breeding seasonality, as based on the monthly ratio of reproductively active and inactive females, are given. External measurements and masses of males and females are tabulated. Records of occurrence based on the number of museum specimens from each locality, and the institution where these specimens are housed, are finally listed for each species. The text is supplemented by a gazetteer, giving the latitudinal and longitudinal coordinates of all the collecting localities. This study is based on some 12 000 museum specimens, the greatest majority housed in the Transvaal Museum collections. During the field work phase of this project, 57 localities were sampled. This yielded the majority of the specimens and the greater part of the data on which this book is based. Information gained from a study of earlier collected material supplements these data files. Additional information such as sight records, field observations, and the published accounts of other scientists, have also been incorporated into the central data files and have been discussed in relation to my own findings. The results of selected studies comprise the discussion. The basic behavioural trends and mean mass of all the carnivore species of the Transvaal are employed to speculate on how interspecific competition is avoided. The distribution of all southern African mammals is employed to statistically evaluate the validity of the biotic zones previously empirically recognized for this subcontinent. The distribution patterns of Transvaal mammals are statistically analysed to subdivide the biotic zones overlying the Transvaal into community types of zoogeographical significance. Other zoogeographical phenomena are discussed in relation to regional species diversity. Reprints of papers arising from this study, and particularly the discussion, are bound in as appendices to this report.
Systematic revision of the golden mole genera : Amblysomus, Chlorotalpa and Calcochloris (Insectivora : Chrysochloromorpha ; Chrysochloridae)
(1995) Bronner, Gary N.; Meester, Jurgens Anthonie Jansen.; Rautenbach, Ignatius Lourens.; Cooke, John Anthony.; Willan, Kenneth Brian Ronald.
Patterns of variation in hyoid morphology, chromosomal properties and craniodental characteristics among ten chrysochlorid species from South Africa were studied to clarify generic relationships among taxa assigned variably to Amblysomus, Chlorotalpa and Calcochloris by previous authors. Intra-specific variation in hyoid morphology was negligible, but inter-specific differences were marked. Similarly, intra-specific karyotypic variation was negligible, except in A. hottentotus, which displayed three cytotypes. These data supported the recognition of Chlorotalpa, Calcochloris and Neamblysomus as taxa distinct from Amblysomus. Only one (presence/absence of M3) of the seven dental traits used by previous authors was consistent enough within species to be taxonomically useful in this work. Dental variability within species appeared to arise from the morphological differences between deciduous and permanent teeth, which may occur together in the same toothrow. Intra-specific craniometric variation in most species involved pronounced sexual size dimorphism, but negligible age-related variation. In the more widespread species, patterns of geographic variation were dominated by divergence in overall size, although subtle differences in cranial shape were also evident. Multivariate analyses confirmed the validity of subspecies in Chlorotalpa sclateri and Calcochloris obtusirostris, and showed that A. hottentotus (as traditionally recognized) includes: four cryptic species; five subspecies (including A. h. iris); and several populations that should be relegated to A. corriae. Inter-specific morphometric variation was dominated by overall size. The species fell into two size groups, and eight phena that differed mainly in skull width, palatal shape, rostrum breadth and claw size. Inter-specific relationships suggested by phenetic analyses of metric and mixed-mode data were, however, incongruent owing to discordance between different data suites. Evolutionary relationships inferred by integrating data suites, using either equal or differential weights, indicated that a strong phylogenetic signal was present in the data. Phylogenetic analyses showed that the differentially weighted treatment was more consilient with character-state distributions. A phylogram based on the differential-weights cladogram was used to derive a revised phylogenetic classification for the Chrysochloridae. Unlike previous treatments, this classification affords Carpitalpa and Neamblysomus generic rank, and assigns C. leucorhina from equatorial Africa to Calcochloris, rather than to Chlorotalpa.