Herman van der Bank

Persistent organochlorine pesticides detected in blood and tissue samples of vultures from different localities in South Africa

Gas chromatography was used to establish the presence of quantifiable residues of 14 persistent chlorinated hydrocarbon pollutants in whole blood, clotted blood, heart, kidney, liver and muscle samples obtained from individual African whitebacked (Pseudogyps africanus), Cape griffon (Gyps coprotheres) and Lappetfaced (Torgos tracheliotos) vultures from different localities in South Africa. The levels of pesticides measured in whole blood samples of live specimens were compared between nestlings from two natural breeding colonies, adults from a wildlife area and birds held in captivity. Statistically significant (P<0.05) differences between populations were detected in geometric means calculated for gamma-BHC (lindane), alpha(cis)-chlordane and alpha-endosulfan. Five of the organochlorine contaminants displayed significant variations between concentrations detected in the clotted blood, organs and muscles excised from vulture carcasses. This includes residues of gamma-BHC, alpha-chlordane, dieldrin, beta-endosulfan and heptachlor epoxide. Values of the respective biocides measured in vulture samples were generally low in comparison to results documented for a number of avian species. Although no threat is posed by any of the organochloride pesticides, continual monitoring of especially breeding colonies is recommended. Furthermore, the suitability of African whitebacked vulture nestlings as basic bioindicators is highly advocated.

A review of the use of allozyme electrophoresis in plant systematics.

Abstract The role of electrophoretic data is discussed as it applies to plant taxonomy and systematic studies. Neis (Am. Nat. 106 (1972) 283–292; Genetics 89 (1978) 583–590) genetic distances calculated for a large number of populations, species and genera were taken from published data. The relation between Neis genetic identity measures and taxonomic rank (populations, species and genera) are shown graphically. The graphs obtained in this way (from 3021 pairs of plant taxa) differ substantially from previous graphs published by Thorpe (Ann. Rev. Ecol. Syst. 13 (1982) 139–168; in: G.S. Oxford, D. Rollinson (Eds.), Protein Polymorphism: Adaptive and Taxonomic Significance, Academic Press, London, 1983, pp. 131–152) and Thorpe and Sole-Cava (Zool. Scripta 23 (1994) 3–18). These authors suggested that the divergence between the different taxonomic ranks is roughly similar across a wide range of taxa. The latter was based on values for 2664 (Thorpe, 1982) and 8060 (Thorpe, 1983) pairs of animal and plant taxa, but the plant data contributed little to the total. For any given taxonomic rank, we found that plants are genetically more closely related than animals (possibly with the exception of birds). This result is important because the empirical relationships of genetic distance measures, to different levels of taxonomic separation, is often used for distinguishing and identifying cryptic or sibling species where conventional methods are unable to resolve systematic problems.

Allopatric differentiation in the Marcusenius macrolepidotus species complex in southern and eastern Africa: the resurrection of M. pongolensis and M. angolensis, and the description of two new species (Mormyridae, Teleostei)

We critically compared local populations of the bulldog fish, Marcusenius macrolepidotus (Peters 1852), from different watersheds, from the furthest south (28° South, South Africa) to the Equator in Kenya. We ascertained allopatric differentiation from topotypical M. macrolepidotus from the Lower Zambezi River (Mozambique) in morphology, electric organ discharges, and molecular genetics for: (1) samples from the Okavango and Upper Zambezi Systems (Botswana and Namibia), (2) samples from South Africas rivers draining into the Indian Ocean, and (3) samples from the East African Tana River (Kenya). Significant genetic distances in the mitochondrial cytochrome b gene and differing ISSR‐PCR profiles corroborate differentiation between the four taxa. We resurrect M. pongolensis (Fowler, 1934) for South Africa (sample 2), and M. angolensis (Boulenger, 1905) for the Quanza River/Angola. We recognize M. altisambesi sp. n. for the Upper Zambezi/Okavango specimens (sample 1), and M. devosi sp. n. for those from Kenya (sample 3).

Evidence for parapatric speciation in the Mormyrid fish, Pollimyrus castelnaui (Boulenger, 1911), from the Okavango-Upper Zambezi River Systems: P. marianne sp. nov., defined by electric organ discharges, morphology and genetics

We report on parapatric speciation in the mormyrid fish, Pollimyrus castelnaui (Boulenger, 1911), from the Okavango and the Upper Zambezi River systems. We recognise samples from the Zambezi River as a distinct species, P. marianne, displaying an eastern phenotype of electric organ discharge (EOD) waveform (Type 3) that is distinct from the western EOD phenotype (Type 1) observed in P. castelnaui samples from the neighbouring Okavango. Samples from the geographically intermediate Kwando/Linyanti River (a tributary of the Zambezi that is also intermittently connected to the Okavango) presented a more variable third EOD phenotype (Type 2). In 13 out of 14 morphological characters studied, the Zambezi River samples differed significantly from P. castelnaui. Morphologically and in EOD characters, the Kwando/Linyanti fish are distinct from both P. castelnaui and P. marianne. Sequence analysis of the mitochondrial cytochrome b gene unambiguously reveals that specimens from the Zambezi River System form a well supported taxon which clearly differs from P. castelnaui from the Okavango (1.5–2.5% sequence divergence). Within specimens from the Kwando–Zambezi System some geographic differentiation can be detected (nucleotide substitutions up to 0.6%); but groups cannot be resolved with certainty. Significant allozyme differences were found between the Okavango and all other EOD types from the Upper Zambezi System, and, within the Zambezi System, between the Kwando (Type 2) and Zambezi (Type 3) individuals. The low Wrights fixation index values, the lack of fixed allele differences, and small genetic distances provide little evidence for speciation between groups within the Zambezi System, but moderate to great fixation index values and significant allele frequency differences were observed between the Okavango and the other fishes. It is concluded that within the Zambezi System, differentiation between Kwando/Linyanti and Zambezi populations (as revealed by morphology and EOD waveform comparisons) is so recent that substantial genetic (allozyme and mitochondrial sequence) differences could not have evolved, or were not detected.

Dynamics of haematology and blood biochemistry in free-living African whitebacked vulture (Pseudogyps africanus) nestlings

Reference values for some haematological- and plasma chemical parameters were established in 33 apparently normal, free-living African whitebacked vulture (Pseudogyps africanus) nestlings. This information can be used in future ornithological research. A total of 27 variables were examined, which include: leucocyte- and erythrocyte counts, haemoglobin concentration, haematocrit, haematimetric indices, glucose, creatinine, urea, total protein, albumin, globulin, albumin/globulin ratio, cholesterol, total lipids, triglycerides, aspartate aminotransferase, cholinesterase, lactate dehydrogenase, alkaline phosphatase, calcium, phosphorus, chloride, potassium, sodium and osmolarity. Blood values of the different parameters were reported on the basis of the ranges and means described for several other raptors and avian species in general. Only five parameters exhibited statistically significant (P<0.05) differences between the two populations assayed. The Sandveld population showed elevated mean corpuscular haemoglobin concentration- (MCHC) and alkaline phosphatase (ALP) levels relative to the Dronfield population, whereas, the latter group displayed higher erythrocyte counts (RBC), potassium- and sodium values than birds from the Sandveld community. Evident dispersion around the means was encountered for estimates of globulin and cholinesterase.

Hippopotamyrus ansorgii species complex in the Upper Zambezi River System with a description of a new species, H. szaboi (Mormyridae)

Kramer, B., Van der Bank, & H., Wink, M. (2004) Hippopotamyrus ansorgii species complex in the Upper Zambezi River System with a description of a new species, H. szaboi (Mormyridae). — Zoologica Scripta, 33, 1–18.

Allozyme and DNA sequence comparisons of nine species of Encephalartos (Zamiaceae)

Phylogenetic relationships between Encephalartos altensteinii Lehmann, E. arenarius R.A. Dyer, E. horridus (Jacquin) Lehmann, E. latifrons Lehmann, E. lehmannii Lehmann, E. longifolius (Jacquin) Lehmann, E. princeps R.A. Dyer and E. trispinosus (Hooker) R.A. Dyer were studied, using E. ferox Bertoloni f. as outgroup. Three continuous and one discontinuous buffer systems were used and gene products of 14 enzyme coding loci were examined by horizontal starch gel-electrophoresis. Genetic variation was studied in a cultivated population of E. lehmannii and the average heterozygosity value for this population is 13.5%, which falls within the range reported for other cycad species. Fixed allele differences between the species studied was not found at any of the loci studied, which suggest that these species are closely related. DNA sequence analysis of rbcL and ITS 1 & 2 genes (1428 and 895 basepairs, respectively) confirmed the close genetic relationships between these taxa. According to ITS and rbcL sequences E. altensteinii and E. princeps are sibling taxa which form a sister group to E. arenarius, E. horridus, E. latifrons, E. lehmannii, E. longifolius, and E. trispinosus. The genetic distances between both groups were 0.12-0.47% for ITS and 0.08-0.16% for rbcL DNA. The results indicate recent (probably pleistocenic) speciation for this group of cycads, and the relationships are discussed with reference to affinities based on morphology and distribution.

Biochemical genetic variation in four wild populations of Aspalathus linearis (Rooibos Tea)

Abstract Four morphologically different populations of Aspalathus linearis were examined by horizontal starch gel electrophoresis to assess levels and patterns of genetic variation and to estimate the amount of genetic differentiation within and between populations. Leaf extracts were surveyed for 13 enzymes, and gene products revealed genetic variation at six (40%) of 15 protein coding loci. The percentages of polymorphic loci range from 6.67 to 26.67% (0.95 criterion), values of 1.07–1.40 were obtained for the mean number of alleles per locus, and average heterozygosities per locus were calculated at 0.016–0.096. The mean genotypic distance index (Nei, 1978) between populations was 0.034. Enzyme electrophoresis appears to be a suitable method for studying genetic variation in A. linearis .

GENETIC VARIATION IN TWO ECONOMICALLY IMPORTANT ALOE SPECIES (ALOACEAE)

Abstract Four morphologically distinct and geographically separated populations of Aloe ferox and one population of A. marlothii were examined by horizontal starch gel electrophoresis to assess levels of genetic variation at 22 protein coding loci. Leaf extracts were surveyed for 26 proteins; gene products revealed no polymorphism in any of the populations studied in the former species, and genetic variation at one locus (4.55%) in the latter species. The percentage of polymorphic loci was 4.76%; a value of 1.05 (±0.05) was obtained for the mean number of alleles per locus, and the average heterozygosity per locus was calculated at 0.022 (±0.022) for A. marlothii . We propose the ecological theory to explain the low levels of genetic variation obtained (i.e. species that are well adapted to their environment need less genetic variation). Isozyme differences between species were encountered at two loci to produce a mean genotypic distance index of 0.056, indicating a high degree of differentiation between species. This is unexpected since the two species studied are closely related and known to produce natural hybrids with A. arborescens . Biochemical markers could not be found to distinguish different chemovars of the two species. The remarkably low levels of genetic variation may be related to the xerophytic habit of the plants, perhaps making them less sensitive to drought stress as a selection pressure.

Biochemical genetic markers to identify two morphologically similar South African Mastomys species (Rodentia: Muridae)

The two common southern African mice species (Mastomys coucha and M. natalensis) are morphologically almost identical, making field identification impossible at present. Specimens from two localities were collected and tissue and blood samples taken. The habitat type of each locality was studied, and a distribution map compiled. A definite correlation between biome-type and species range was found to be present. Three isozyme markers were identified: glucose phosphate isomerase in liver, and two general (non-specific) protein coding loci in muscle. In addition, we also identified species characteristic haemoglobin components in both species. This is the first study to report genetic variation within, and differentiation between these species. Our results are of medical importance because Mastomys coucha carries bubonic plague and M. natalensis carries Lassa Fever.