Aethomys Chrysophilus Research Articles

Prevalence and genetic diversity of Bartonella spp. in wild small mammals from South Africa.

Bartonella spp. are intracellular bacteria associated with several re-emerging human diseases. Small mammals play a significant role in the maintenance and spread of Bartonella spp. Despite the high small mammal biodiversity in South Africa, there is limited epidemiological information regarding Bartonella spp. in these mammals. The main aim of this study was to determine the prevalence and genetic diversity of Bartonella spp. from wild small mammals from 15 localities in 8 provinces of South Africa. Small mammals (n = 183) were trapped in the Eastern Cape, Free State, Gauteng, Limpopo, Mpumalanga, Northern Cape, North West, and Western Cape provinces of South Africa between 2010 and 2018. Heart, kidney, liver, lung, and spleen were harvested for Bartonella DNA screening, and prevalence was determined based on the PCR amplification of partial fragments of the 16S-23S rRNA intergenic spacer (ITS) region, gltA, and rpoB genes. Bartonella DNA was detected in Aethomys chrysophilus, Aethomys ineptus, Gerbillurus spp., Lemniscomys rosalia, Mastomys coucha, Micaelamys namaquensis, Rhabdomys pumilio, and Thallomys paedulcus. An overall prevalence of 16.9% (31/183, 95% CI: 12.2%-23%) was observed. Bartonella elizabethae, Bartonella grahamii, and Bartonella tribocorum were the zoonotic species identified, while the remaining sequences were aligned to uncultured Bartonella spp. with unknown zoonotic potential. Phylogenetic analyses confirmed five distinct Bartonella lineages (I-V), with lineage IV displaying strong M. coucha host specificity. Our results confirm that South African wild small mammals are natural reservoirs of a diverse assemblage of Bartonella spp., including some zoonotic species with high genetic diversity, although prevalence was relatively low.IMPORTANCESmall mammals play a significant role in the maintenance and spread of zoonotic pathogens such as Bartonella spp. Despite the high small mammal biodiversity in southern Africa including South Africa, there is limited epidemiological information regarding Bartonella spp. in these mammals across the country. Results from our study showed the liver and spleen had the highest positive cases for Bartonella spp. DNA among the tested organs. Bartonella elizabethae, B. grahamii, and B. tribocorum were the three zoonotic species identified and five distinct Bartonella lineages (I-V) were confirmed through phylogenetic analyses. To the best of our knowledge, this study presents the first extensive nuclear diversity investigation of Bartonella spp. in South African small mammals in South Africa.

Forest holds high rodent diversity than other habitats under a rapidly changing and fragmenting landscape in Quirimbas National Park, Mozambique

Habitat loss and fragmentation have widely recognised as the major challenge for biodiversity conservation across the world. This is particularly true in Quirimbas National Park (QNP) where holds unique fauna, and anthropogenic factors have been intensifying leading to a significant loss of biodiversity, especially rodents which play a vital role for the functioning of ecosystems. However, studies assessing rodent diversity, and deeply analysing spatiotemporal dynamics of this vulnerable landscape are still lacking although they are decisive for successful wildlife management and monitoring. This study aimed to assess the rodent diversity, change intensity and its driving forces, and fragmentation of different habitat types in QNP. Multi-temporal satellite images and field data were used to analyse the habitat fragmentation and change intensities at three levels (time interval, category, and transition) from 1990 to 2020. The stratified sampling and capture-recapture approaches were used to survey rodents in three habitats: forest, grassland and cropland. Ecological metrics were employed to measure rodent diversity, distribution and composition. Statistical tests were applied to check differences in rodent abundance and diversity among habitats. The findings revealed an increase in fragmentation of all habitats, and forest experienced the highest losses (107.3 km2) during 1990–2020. The annual rate change intensity was fast from 2010 to 2020. Cropland and built-up land experienced greater intensively gains and losses, while the annual change intensity of forest was dormant over time. Cropland and built-up land expanded at the expense of forest from 2010 to 2020, whereas from 2000 to 2010, cropland's gain targeted intensively grassland, built-up land and water body, and avoided forest. We recorded four rodent species: Acomys spinosissimus, Mastomys verreauxii, Dasymys incomtus and Aethomys chrysophilus; the last three species are new records for the park. Forest revealed the highest rodent diversity (Shannon entropy = 3.0), and the total species richness was comparable to previous studies in eastern Africa. We found significant differences in rodent abundance among habitats. Turnover and nestedness were the main cause of the overall beta diversity. This study can provide vital information for wildlife managers to better understand the process of habitat loss and fragmentation and its implication to biodiversity, which is crucial for applying appropriate conservation management.

Effects of prescribed burning on rodents in an East African woodland ecosystem

AbstractThe name “miombo” is a vernacular term for the forests in central, southern, and eastern Africa that are dominated by the closely related legume family genera Brachystegia, Julbernardia and/or Isoberlinia. Prescribed burning is a common management practice in most miombo woodland in protected areas that highly influences vegetation structure and composition which in turn influences small mammals' distribution and abundance. This practice if not checked might significantly affect the ecosystems. We investigated the effects of prescribed burning on rodent's ecology in the miombo woodland ecosystem in the Selous game reserve, Tanzania, between July 2018 and June 2020. A total of 473 individuals comprising six rodent species; Acomys ngurui (31.50%), Aethomys chrysophilus (28.96%), Mastomys natalensis (18.82%), Lemniscomys rosalia (14.16%), Mus minutoides (2.33%), Paraxerus flavovittis (0.85%) and two insectivorous shrew species; Petrodromus tetradactylus (3.17%) and Crocidura hitra (0.21%) were captured during 14,112 trap nights. There were no statistically significant differences in the abundance of A. ngurui between burnt and unburnt areas but its abundance was statistically significantly different between seasons. M. natalensis abundance was not statistically significantly different between burnt and unburnt areas or across seasons. The burnt sites had the highest species diversity than the unburnt in both wet and dry seasons. A. ngurui and M. natalensis survival and recruitment between burnt and unburnt sites were not statistically significantly different. The study shows that prescribed burning has an effect on specific species and demographic characteristics both positive and negative.

Small mammal species diversity and distribution in the Selous ecosystem, Tanzania

Threats to ecosystems are ever increasing from different drivers mostly being linked to anthropogenic activities. This has brought about various measures to restore/protect the wildlife in these areas. Considering the background of most protected areas in East Africa, small mammals have been given least attention, compared with large mammals, although they play a fundamental role in maintaining ecosystem health. It is therefore necessary to understand how small mammals are distributed in any given ecosystem as a baseline information to enable holistic and informed management. We investigated the diversity and distribution of small mammals in the Selous ecosystem, Tanzania. Two methods were used; Capture Mark Recapture (CMR) using grids of 70 m x 70 m and random placement of havahart traps in the selected habitats. Between July 2018 and June 2020, a total of 887 individuals belonging to 20 species were captured in 28 224 trap nights with 3% trap success. The small mammal species captured consisted of rodents (91.8%), Macroscelidea (3.9%), Carnivores (2.4%) Eulipotyphla (1.6%), and Primates (0.3%). Acomys ngurni (36%) and Aethomys chrysophilus (17%) were the most captured species, whereas Atilax paludinosus (0.23%), Helogale pervula (0.23%), Rattus rattus (0.23%) and Galerella sanguinea (0.11%) were the least contributing species. Acomys ngurui and Lemniscomys rosalia were the most distributed species occurring in all four habitats, whereas Cricetomys ansorgei, Rattus rattus, Mungos mungo and Genetta genetta had low occurrence. Grammomys selousi is reported for the first time in the northern part of the Rufiji River. Acomys ngurni abundance differed significantly (χ2 = 12, df = 3, p = 0.007) between the four habitats being higher in the seasonal riverine forest and across seasons (χ2 = 6, df = 2, p = 0.049), with more individuals occurring in the wet season. The Sable Forest habitat had the highest species diversity (H' = 2.065) and the lowest diversity (H' = 1.506) was recorded in perennial riverine forest/thickets. The highest species diversity (H' = 1.65) was recorded in the dry season and the lowest diversity in the wet season (H' = 1.445). Most small mammals were associated with seasonal riverine forest than other habitats. Overall, the results from this study show that, the park is rich in small mammal fauna. Therefore, considerations in updating the General Management Plan (GMP) and other plans to include the small mammals in the park management actions is recommended.

Two New Species of Sucking Lice (Phthiraptera: Anoplura: Hoplopleuridae and Polyplacidae) from Grant's Rock Mouse, Micaelamys granti, in South Africa.

Two new species of sucking lice (Phthiraptera: Anoplura), Hoplopleura granti n. sp. (Hoplopleuridae) and Polyplax megacephalus n. sp. (Polyplacidae), are described from Grant's rock mouse, Micaelamys granti (Wroughton), from Northern Cape Province, South Africa. Adults of both sexes are illustrated via line drawings and differential interference contrast microscopy images, and are compared with previously described related species that parasitize related hosts: Hoplopleura patersoni Johnson from Aethomys chrysophilus (de Winton) (red veld rat), Aethomys kaiseri (Noack) (Kaiser's aethomys), and Micaelamys namaquensis (A. Smith) (Namaqua rock mouse); Hoplopleura aethomydis Kleynhans from M. namaquensis; Polyplax praomydis Bedford from A. chrysophilus and M. namaquensis; and Polyplax solivaga Johnson from A. chrysophilus. It is not known if these new species of lice are vectors of any pathogens.

Morphometric analysis of the gastrointestinal tract of four African muroid rodent species (Rhabdomys dilectus, Rhabdomys pumilio, Aethomys chrysophilus, and Lemniscomys rosalia).

Several muroid rodent species are distributed throughout southern Africa. Some species are reportedly classified as opportunistic omnivorous rodents consuming plant, seed, and insect material. This study aims to provide a detailed morphometric analysis of the gastrointestinal tract (GIT) of four such omnivorous species, including stomach content analysis. Fixed GIT specimens (n = 5 of each) of Rhabdomys dilectus (Mesic four-striped grass mouse), Rhabdomys pumilio (Xeric four-striped grass mouse), Aethomys chrysophilus (Red rock rat), and Lemniscomys rosalia (Single-striped grass mouse) were weighed. Length and circumference measurements of each anatomically distinct GIT region were determined to calculate the basal surface area (BSA). Histological sections from each GIT region were used to calculate a surface enlargement factor (SEF). The BSA and SEF were multiplied to calculate the luminal surface area (LSA) of each GIT region. Stomach content was analyzed both macroscopically and histologically. All species had a similar GIT morphology, namely a unilocular, hemiglandular stomach with a clear limiting ridge, which indicated the transition from stratified squamous epithelium to glandular epithelium. A large loosely spiralled cecum was present in all species. A narrowing of the cecal apex accompanied by lymph aggregates, confirmed histologically in both Rhabdomys species, indicated a cecal appendix. A single short colonic loop with a unique folding pattern for each species was present in the proximal colon. The colonic mucosal surface presented with proximal V-shaped, and distal longitudinal folds. Intermediate transitional S-shaped folds were present in three species (R. dilectus, R. pumilio, and L. rosalia). Colonic mucosal folds indicated hindgut specialization similar to other muroid rodents. The hindgut specialization was further supported by morphometric analysis, which indicated large BSA and LSA measurements in the cecum and colon. These adaptations are consistent with herbivory, despite stomach content analysis revealing omnivorous tendencies.

Identity of Haemaphysalis (Rhipistoma) muhsamae Santos Dias, 1954 (Acari: Ixodidae) and H. (R.) subterra Hoogstraal, El Kammah & Camicas, 1992, parasites of carnivores and rodents in eastern and southern Africa.

Haemaphysalis (Rhipistoma) muhsamae Santos Dias, 1954 (Acari: Ixodidae) and H. (R.) subterra Hoogstraal, El Kammah & Camicas, 1992, are redescribed based on males and females. Adults of H. muhsamae were mostly collected from various mongooses (Carnivora: Herpestidae) but also from the striped polecat, Ictonyx striatus (Perry) (Carnivora: Mustelidae), serval, Leptailurus serval (Schreber) (Carnivora: Felidae), red veld rat, Aethomys chrysophilus (de Winton) and Selinda veld rat, Aethomys silindensis Roberts (Rodentia: Muridae) in Botswana, Kenya, Mozambique, South Africa, Tanzania and Zimbabwe. Adults of H. subterra were mostly found on various species of African mole rats, Tachyoryctes spp. (Rodentia: Spalacidae) but also on striped polecat, I. striatus and slender mongoose, Galerella sanguinea (Rüppell) (Carnivora: Herpestidae) in Ethiopia and Kenya. Males and females of both species can be differentiated from each other and other H. spinulosa-like ticks by their size, pattern of punctations on conscutum/scutum, shape of genital structures, shape and size of posterodorsal and posteroventral spurs on palpal segment II, hypostome dentition, and shape and size of spurs on coxae. Taxonomic issues of both species and those related to the identity of H. (R.) spinulosa Neumann, 1906 are discussed and a neotype of H. muhsamae has been designated.

DNA barcoding for identification of cryptic species in the field and existing museum collections: a case study of Aethomys and Micaelamys (Rodentia: Muridae)

DNA barcoding has been proposed as a method for species identification. However, this method has been criticised for its over-reliance on a single mitochondrial gene. In this study, four mitochondrial gene regions and one nuclear gene region were used to investigate their different abilities to identify tissue associated with museum specimens of Aethomys chrysophilus, Aethomys ineptus and Micaelamys namaquensis. Aethomys chrysophilus and the more recently elevated A. ineptus are indistinguishable on morphological grounds; however, their ranges are largely parapatric with only one syntopic locality currently known. All of the mitochondrial gene regions were able to separate M. namaquensis from A. chrysophilus and A. ineptus, but they varied in their abilities to resolve differences between A. chrysophilus and A. ineptus. The sequence results identified a specimen from KwaZulu-Natal that was misclassified and should have been identified as A. ineptus. Seven specimens that had not been reclassified following the elevation of A. ineptus to species level were identified as A. ineptus. Individuals of A. chrysophilus from Malawi could not be classified as either A. chrysophilus or A. ineptus, and may be a hybrid or a new, distinct species. This study indicates that DNA barcoding may be used to separate M. namaquensis from A. chrysophilus and A. ineptus, and although it was not able to separate A. chrysophilus and A. ineptus, it did indicate specimens from Malawi may be a new cryptic species.

Habitat-specific shaping of proliferation and neuronal differentiation in adult hippocampal neurogenesis of wild rodents

Daily life of wild mammals is characterized by a multitude of attractive and aversive stimuli. The hippocampus processes complex polymodal information associated with such stimuli and mediates adequate behavioral responses. How newly generated hippocampal neurons in wild animals contribute to hippocampal function is still a subject of debate. Here, we test the relationship between adult hippocampal neurogenesis (AHN) and habitat types. To this end, we compare wild Muridae species of southern Africa [Namaqua rock mouse (Micaelamys namaquensis), red veld rat (Aethomys chrysophilus), highveld gerbil (Tatera brantsii), and spiny mouse (Acomys spinosissimus)] with data from wild European Muridae [long-tailed wood mice (Apodemus sylvaticus), pygmy field mice (Apodemus microps), yellow-necked wood mice (Apodemus flavicollis), and house mice (Mus musculus domesticus)] from previous studies. The pattern of neurogenesis, expressed in normalized numbers of Ki67- and Doublecortin(DCX)-positive cells to total granule cells (GCs), is similar for the species from a southern African habitat. However, we found low proliferation, but high neuronal differentiation in rodents from the southern African habitat compared to rodents from the European environment. Within the African rodents, we observe additional regulatory and morphological traits in the hippocampus. Namaqua rock mice with previous pregnancies showed lower AHN compared to males and nulliparous females. The phylogenetically closely related species (Namaqua rock mouse and red veld rat) show a CA4, which is not usually observed in murine rodents. The specific features of the southern environment that may be associated with the high number of young neurons in African rodents still remain to be elucidated. This study provides the first evidence that a habitat can shape adult neurogenesis in rodents across phylogenetic groups.

Breeding Dynamics of Rodent Species Inhabiting Farm—Fallow Mosaic Fields in Central Tanzania†

The breeding dynamics of three species of rodents, Mastomys natalensis, Aethomys chrysophilus and Gerbilliscus vicina were investigated in a seasonal environment (wet versus dry) in Berega in the eastern parts of central Tanzania. Berega has a distinct unimodal rainfall pattern, with most rainfall from November to April/May. We hypothesized that breeding of rodents in central Tanzania would be confined to the wet season, when unlimited resources would be available for reproduction. We provide evidence of breeding discontinuity in the three species, showing that breeding was seasonally restricted to the wet season and early in the dry season. The observed discontinuity could largely be ascribed to variation in primary productivity between the wet and dry seasons. Reproductively active females were found in the population as early as November, a month into the rainy season, but when early rains occurred, some individuals were already breeding in October. Breeding was more intensive in the latter part of the wet season (March–May) and completely ceased during the dry season. For M. natalensis, survival was highest in the wet period and low in the dry season. The study provides knowledge on the breeding dynamics of rodents in central Tanzania, which can help farmers to take proactive rodent management decisions to prevent high rodent densities and reduce crop damage in the fields. Application of control measures by the community early in the season when populations of reproductive females is lowest will be most rewarding.

Breeding dynamics of rodent species inhabiting farm–fallow mosaic fields in Central Tanzania

The breeding dynamics of three species of rodents, Mastomys natalensis, Aethomys chrysophilus and Gerbilliscus vicina were investigated in a seasonal environment (wet versus dry) in Berega in the eastern parts of central Tanzania. Berega has a distinct unimodal rainfall pattern, with most rainfall from November to April/May. We hypothesized that breeding of rodents in central Tanzania would be confined to the wet season, when unlimited resources would be available for reproduction. We provide evidence of breeding discontinuity in the three species, showing that breeding was seasonally restricted to the wet season and early in the dry season. The observed discontinuity could largely be ascribed to variation in primary productivity between the wet and dry seasons. Reproductively active females were found in the population as early as November, a month into the rainy season, but when early rains occurred, some individuals were already breeding in October. Breeding was more intensive in the latter part of the wet season (March–May) and completely ceased during the dry season. For M. natalensis, survival was highest in the wet period and low in the dry season. The study provides knowledge on the breeding dynamics of rodents in central Tanzania, which can help farmers to take proactive rodent management decisions to prevent high rodent densities and reduce crop damage in the fields. Application of control measures by the community early in the season when populations of reproductive females is lowest will be most rewarding.

Natural hosts of the larvae of <i>Nuttalliella</i> sp. (<i>N. namaqua</i>?) (Acari: Nuttalliellidae)

The first collection of unengorged and fully engorged larvae of Nuttalliella sp. (N. namaqua?) from the murid rodents Micaelamys namaquensis, Aethomys chrysophilus and Acomys spinosissimus in Limpopo Province and from M. namaquensis in the Northern Cape Province, South Africa, is documented. A total of nine larvae were collected from two M. namaquensis in the Soutpansberg mountain range in the Limpopo Province during April 2009. During the last week of September 2011, 221 larvae were collected from rodents at the same locality and 10 of 48 M. namaquensis, 6 of 12 Ae. chrysophilus and 3 of 14 Ac. spinosissimus were infested. One of the M. namaquensis harboured 53 larvae. Five larvae were collected from two M. namaquensis in the Northern Cape Province. Total genomic DNA was extracted from two larvae and a region of the 18S rRNA gene was sequenced for these. BLASTn searches revealed similarity between these specimens and the Nuttalliella sequences published on GenBank.

Spatial and temporal population dynamics of rodents in three geographically different regions in Africa: Implication for ecologically-based rodent management

As part of a three-year study to develop ecologically-based rodent management (EBRM) in southern Africa, a capture–mark–recapture study was carried out in Tanzania, Namibia and Swaziland to establish the demographic patterns and population dynamics of rodents. Two study grids were established in each country. In Tanzania, ten species of rodents and one shrew (Crocidura sp.) were identified in the study area. The rodent species consisted of Mastomys natalensis, Aethomys chrysophilus, Arvicanthis neumanni, Gerbilliscus vicina, Acomys spinosissimus, Lemniscomys griselda, Lemniscomys zebra, Rattus rattus, Graphiurus sp. and Mus minutoides. Mastomys natalensis was dominant and contributed more than 70% of the captures. In Namibia, five species were captured, namely Mastomys natalensis, Gerbilliscus leucogaster, Saccostomus campestris, Mus minutoides and Steatomys pratensis. Mastomys natalensis contributed about 50% of the captures. In Swaziland, only M. natalensis was captured in the study grids. There was a clear pattern in the population dynamics, with breeding confined to the wet seasons in the three countries. Mastomys natalensis was the dominant pest species, for which EBRM should focus on. The highest population density of M. natalensis occurred during and after the rains, which coincided with the most susceptible phenological stage of crops. The breeding seasonality and density fluctuations observed in the three countries conform with observations made elsewhere in Africa, which support the hypothesis that rainfall events promote primary productivity on which murid rodents depend. Development of EBRM in these countries will be determined by the local conditions and how they influence the demographic processes of the rodent populations. EBRM should make use of the available ecological knowledge of the local rodent pest species and the focus should be on (ecological) management practices applicable at the community level including community based intensive trapping, field hygiene, removing cover and sources of food for rodents.

An analysis of the Aethomys (Murinae) community from Langebaanweg (Early Pliocene, South Africa) using geometric morphometrics

Subsequent to the initial description of two Aethomys species ( Aethomys adamanticola and Aethomys modernis) at the Early Pliocene site of Langebaanweg (LBW), an increase in sample size led to the secure identification of a third, as yet, undescribed species. In addition to this new species, three morphs of existing species, or possibly three new species, were also recognized. Geometric morphometrics was used to explore the relationship of fossil species and morphs with extant Aethomys species, and to assess the intra and inter-specific variation in the size and shape of modern, as well as the LBW, Aethomys specimens. Geometric morphometrics indicates a marked similarity in the upper first molar (M 1) shape between all the analyzed species, extant and extinct, and suggests the persistence, over a significant period of time, of a prototype Aethomys M 1 shape. The relative warp analyses indicate some overlap in shape between the two modern species, Aethomys chrysophilus and Aethomys namaquensis, as well as some inter-specific variation. These two species differ significantly from one another in terms of size. Variability in terms of size and to a minor extent, shape, was also evident in the fossil Aethomys, and it was concluded that the various fossil morphs investigated did not represent new species, or intra-specific sexual dimorphism, but rather, intra-specific variability in size and shape. Interestingly, the newly-identified LBW Aethomys species, which is similar in appearance to the extant east African Aethomys kaiseri, also showed a similarity in shape and size to A. adamanticola. These results indicate that geometric morphometrics has limitations when differentiating between morphologically similar species. The presence of Aethomys in Namibia at around 10.5 to 9.5 Ma, the degree of speciation of Aethomys at LBW, and the similarity of the LBW fossil species to the modern ones (including an East African species), provides good evidence for a southern African origin for modern Aethomys.

Aethomys chrysophilus (Rodentia: Muridae)

Abstract The genus Aethomys currently includes 11 species, but recent evidence indicates a need for taxonomic revision of the genus. Aethomys chrysophilus (De Winton, 1897) is a muroid rodent commonly called the red veld rat. A medium-sized rodent with a long, sparsely haired tail, A. chrysophilus is largely parapatric with its sibling species, A. ineptus, and in areas of co-occurrence, determination of chromosome number, mitochondrial DNA analysis, or morphology of spermatozoa are required to distinguish A. chrysophilus from A. ineptus. Endemic to Africa, A. chrysophilus is found in savanna–woodland habitats that include varying combinations of grass–herbaceous ground cover, shrub understory, and miombo or mopane woodlands. It is not of special conservation concern.

Intra‐individual variation in sperm tail length in murine rodents

AbstractIn eutherian mammals, there are marked interspecific differences in sperm head shape and tail length. In a few species, sperm head variability occurs but intra‐individual variation in sperm tail length has rarely been investigated or commented upon. Here, we ask the question: Do murine rodent species that have variable sperm head shapes exhibit greater intra‐individual variation in sperm midpiece and total tail lengths than closely related species where little, or no, sperm head variability occurs? From three separate lineages, we selected three pairs of murine rodents, one of which has monomorphic, and the other variable, sperm head shape. These were from southern Asia the bandicoot rats Bandicota bengalensis and Bandicota indica, from southern Africa the veld rats, Aethomys chrysophilus and Aethomys ineptus and from Australia the fawn hopping mouse Notomys cervinus and the spinifex hopping mouse Notomys alexis. Cauda epididymal sperm smears were prepared and sperm midpiece and total tail lengths were determined. A linear mixed‐effects model was used to estimate intra‐individual variance. The results showed that in all three species where there are variable sperm head shapes (B. indica, A. ineptus and N. alexis), statistically significantly greater intra‐individual variability of sperm midpiece and total tail lengths occurs (P<0.0001 in all cases). These species all have relatively smaller testes mass compared with the closely related species with monomorphic sperm populations. This suggests that depressed levels of intermale sperm competition may result in the occurrence of variability in not only the divergent sperm head shape but also in the length of the midpiece as well as that of the total length of the sperm tail.

Habitat preferences of small mammals in the Katavi ecosystem of western Tanzania

We sampled small mammals in numerous habitat types throughout the wet and dry seasons in and around Katavi National Park, a remote protected area in western Tanzania consisting of miombo woodland and seasonal floodplains. Although trap success was relatively low (6.6%), a minimum of 23 species were caught in over 11,000 trap nights. These were Crocidura hirta, Crocidura luna, Saccostomus campestris, Dendromus mystacalis, Steatomys pratensis, Tatera boehmi, Tatera leucogaster, Acomys spinosissimus, Aethomys chrysophilus, Aethomys kaiseri, Arvicanthis niloticus, Grammomys dolichurus, Lemniscomys rosalia, Lemniscomys striatus, Mastomys natalensis, Mus musculoides, Mus triton, Pelomys fallax, Graphiurus murinus, Petrodromus tetradactylus and probably Crocidura nanilla, an unidentified species of Mus, and an unidentified rodent species. Overall species richness and abundance did not differ between wet and dry periods of the year. There were few differences in species richness between major habitat types but relative abundance was the highest in cultivated landscapes. Species communities differed between habitats and detailed environmental measures showed that species were more diverse and lived at greater abundance in taller vegetation. Species-specific habitat preferences uncovered here extend a number of findings from several earlier studies in miombo woodland. This study highlights the importance of taking quantitative measures of vegetation at both coarse and fine scales, and the necessity of trapping across a wide variety of habitats.

MITOCHONDRIAL DNA DIFFERENTIATION BETWEEN TWO SPECIES OF AETHOMYS (RODENTIA: MURIDAE) FROM SOUTHERN AFRICA

The morphological identification of cryptic rodent species has historically been problematic. At best, many cryptic species have been identified by chromosomal differences. However, to study the life histories of such rodent species, there is a need for a molecular technique for cryptic species identification that does not involve destructive sampling. In this manuscript we examine mitochondrial DNA (mtDNA) cytochrome-b genetic variation in 2 cryptic murid rodent species, the red veld rat (Aethomys chrysophilus) and the Tete veld rat (A. ineptus) from southern Africa. Phylogenetic and phylogeographic analyses of these sequences showed reciprocal monophyly between populations of the 2 species in southern Africa, but no support for monophyly of A. chrysophilus from southern and eastern Africa. This suggests that the analysis of mtDNA can be used to distinguish these 2 sister species in southern Africa. However, these results need to be investigated further by DNA analyses of type specimens, topotypical material, or both from adjacent localities.

The systematic position of some Ethiopian Nippostrongylinae (Nematoda, Trichostrongylina, Heligmosomoidea) from the National Collection of Animal Helminths, Onderstepoort, South Africa

The taxonomic status of some nippostrongyline nematodes deposited in the National Collection of Animal Helminths, Onderstepoort, is revised. Heligmonina boomkeri n. sp. is described from Aethomys chrysophilus from South Africa. The most closely related species by the body measurements and the pattern of the caudal bursa is Heligmonina bignonensis Diouf, Bâ & Durette-Desset, 1997, a parasite of Mastomys erythroleucus from Senegal. It differs from the new species mainly in the number of ventral cuticular ridges at mid-body (four versus five) and the left ala in the male is shorter than the body diameter. The systematic position of Heligmonina spira (Ortlepp, 1939) and Neoheligmonella capensis (Ortlepp, 1939) is confirmed here through their synlophe, which was not previously studied.

Small mammals as hosts of immature ixodid ticks

Two hundred and twenty-five small mammals belonging to 16 species were examined for ticks in Free State, Mpumalanga and Limpopo Provinces, South Africa, and 18 ixodid tick species, of which two could only be identified to genus level, were recovered. Scrub hares, Lepus saxatilis, and Cape hares, Lepus capensis, harboured the largest number of tick species. In Free State Province Namaqua rock mice, Aethomys namaquensis, and four-striped grass mice, Rhabdomys pumilio, were good hosts of the immature stages of Haemaphysalis leachi and Rhipicephalus gertrudae, while in Mpumalanga and Limpopo Provinces red veld rats, Aethomys chrysophilus, Namaqua rock mice and Natal multimammate mice, Mastomys natalensis were good hosts of H. leachi and Rhipicephalus simus. Haemaphysalis leachi was the only tick recovered from animals in all three provinces.