Petrodromus Research Articles

Four-toed sengi (Petrodromus tetradactylus, Afrotheria, Mammalia) museomics reveals a crucial role of East African forests in macroscelidean diversification

Abstract Sengis (Macroscelidea) are members of the Afroinsectivora, a group of mammals belonging to the supercohort Afrotheria. Sengis’ low population densities and their distribution, which includes politically unstable regions with ongoing armed conflicts, hinder contemporary sampling of comprehensive datasets. We overcome this obstacle for the species Petrodromus tetradactylus, one of the most widely distributed sengi species, by utilizing 44 historical museum samples from multiple natural history museums. These historical samples were combined with newly generated or published data of 11 modern samples, thus creating a dataset of 55 P. tetradactylus individuals covering most of the species’ distribution. Phylogenetic reconstruction with 11 nuclear loci in conjunction with mostly complete mitochondrial genomes reveals multiple deeply divergent and formerly unknown lineages within this monotypic genus, highlighting the need for a taxonomic revision. Furthermore, we can show that the assumed allopatric distribution of P. tetradactylus in Central Africa most likely represents a sampling artifact. Biogeographic character mapping indicates that the African forest system and its dynamics through climate fluctuations shaped the evolutionary and biogeographic history of this taxon. We show that lineages within Petrodromus that were able to adapt to dryer woodland ecosystems are much more widely distributed than lineages restricted to moist forest systems. The evolution and radiation of the four-toed sengi (P. tetradactylus) mirrors the patterns of its distant relative, the giant sengis (Rhynchocyon) in both ecotype variation and overall distribution, implying a significant influence of climate and landscape features in shaping diversification.

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.

Drawn out of the shadows: Surveying secretive forest species with camera trap distance sampling

Abstract With animal species disappearing at unprecedented rates, we need an efficient monitoring method providing reliable estimates of population density and abundance, critical for the assessment of population status and trend. We deployed 160 camera traps (CTs) systematically over 743 locations covering 17,127 km2 of evergreen lowland rainforest of Salonga National Park, block South, Democratic Republic of the Congo. We evaluated the applicability of CT distance sampling (CTDS) to species different in size and behaviour. To improve precision of estimates, we evaluated two methods estimating species' availability (‘A’) for detection by CTs. We recorded 16,700 video clips, revealing 43 different animal taxa. We estimated densities of 14 species differing in physical, behavioural and ecological traits, and extracted species‐specific availability from available video footage using two methods (a) ‘ACa’ (Cappelle et al. [2019] Am. J. Primatol., 81, e22962) and (b) ‘ARo’ (Rowcliffe et al. [2014] Methods Ecol. Evol. 5, 1170). With sample sizes being large enough, we found minor differences between ACa and ARo in estimated densities. In contrast, low detectability and reactivity to the camera were main sources of bias. CTDS proved efficient for estimating density of homogenously rather than patchily distributed species. Synthesis and applications. Our application of camera trap distance sampling (CTDS) to a diverse vertebrate community demonstrates the enormous potential of this methodology for surveys of terrestrial wildlife, allowing rapid assessments of species' status and trends that can translate into effective conservation strategies. By providing the first estimates of understudied species such as the Congo peafowl, the giant ground pangolin and the cusimanses, CTDS may be used as a tool to revise these species' conservation status in the IUCN Red List of Threatened Species. Based on the constraints we encountered, we identify improvements to the current application, enhancing the general applicability of this method.

African chiggers (Acariformes: Trombiculidae) in the collection of Alex Fain, with a description of a new genus and three new species

A series of African chigger mites from the collection donated by Alex Fain (1912-2009) to the Royal Belgian Institute of Natural Sciences is revised. One new genus and species, Makwacarus petrodromi n. gen., n. sp. from an elephant shrew Petrodromus tetradactylus tordayi Thomas and two new species, Herpetacarus junkeri n. sp. from a snake Boaedon fuliginosus (Boie) and Microtrombicula livingstonei n. sp. from a lizard Holaspis guentheri Gray, are described from DR Congo. One new subjective synonym is proposed: Schoutedenichia musaranei Taufflieb, 1966 (= Schoutedenichia tanzaniaensis Goff, 1983, n. syn). Nineteen species have been recorded in new countries and/or on new hosts for the first time. Nine of them have been found outside their type localities for the first time. In total, the examined collection now includes 27 species belonging to 14 genera and collected from rodents, bats, tenrecs, elephant shrews, primates, birds, lizards and snakes of DR Congo, Rwanda, Kenya, Cameroon, Côte d’Ivoire, Senegal and South Africa

Assessing Monkeypox Virus Prevalence in Small Mammals at the Human-Animal Interface in the Democratic Republic of the Congo.

During 2012, 2013 and 2015, we collected small mammals within 25 km of the town of Boende in Tshuapa Province, the Democratic Republic of the Congo. The prevalence of monkeypox virus (MPXV) in this area is unknown; however, cases of human infection were previously confirmed near these collection sites. Samples were collected from 353 mammals (rodents, shrews, pangolins, elephant shrews, a potamogale, and a hyrax). Some rodents and shrews were captured from houses where human monkeypox cases have recently been identified, but most were trapped in forests and agricultural areas near villages. Real-time PCR and ELISA were used to assess evidence of MPXV infection and other Orthopoxvirus (OPXV) infections in these small mammals. Seven (2.0%) of these animal samples were found to be anti-orthopoxvirus immunoglobulin G (IgG) antibody positive (six rodents: two Funisciurus spp.; one Graphiurus lorraineus; one Cricetomys emini; one Heliosciurus sp.; one Oenomys hypoxanthus, and one elephant shrew Petrodromus tetradactylus); no individuals were found positive in PCR-based assays. These results suggest that a variety of animals can be infected with OPXVs, and that epidemiology studies and educational campaigns should focus on animals that people are regularly contacting, including larger rodents used as protein sources.

Petrosal and Bony Labyrinth Morphology Supports Paraphyly of Elephantulus Within Macroscelididae (Mammalia, Afrotheria)

Interest in the phylogeny of Macroscelididae (sengis or elephant shrews) has been prompted by molecular studies indicating that Elephantulus rozeti is best placed as the sister group of Petrodromus tetradactylus (this clade being in turn the sister taxon to Macroscelides proboscideus) than among other species of the genus Elephantulus. Until now, no discrete morphological characters have been proposed to support the grouping of E. rozeti, Petrodromus, and Macroscelides into this single so-called ‘Panelephantulus’ clade. Here, we employed μCT scanning in order to investigate the petrosal and bony labyrinth (bony capsule of the inner ear) morphology of most species of extant Macroscelididae. We performed a cladistic analysis on ear traits and found that despite some convergences (e.g., concerning the bony arterial canals in Macroscelides and Rhynchocyon) the middle and inner ear morphology furnishes significant support for the ‘Panelephantulus’ clade. In our analysis, this clade is unambigously supported by the presence of a fully ossified stapediofacial tube. Two additional characters (the presence of a bony septum at the mouth of the fenestra cochleae dividing the D3 sinus into two distinct cavities and the absence of an accessory lateral pneumatic fossa) could also support ‘Panelephantulus.’ These newly discovered morphological characters support the molecular phylogenies published and highlight the importance of coding hitherto difficult to sample morphologies within cladistic analyses using micro-CT techniques. Taxonomic implications are briefly discussed.

Ticks of four-toed elephant shrews and Southern African hedgehogs

Several studies on ticks infesting small mammals, including elephant shrews, have been conducted in South Africa; however, these studies have included only a single four-toed elephant shrew and no hedgehogs. This study thus aimed to identify and quantify the ixodid ticks infesting four-toed elephant shrews and Southern African hedgehogs. Four-toed elephant shrews (Petrodromus tetradactylus) were trapped in dense shrub undergrowth in a nature reserve in north-eastern KwaZulu-Natal. They were separately housed, first in cages and later in glass terraria fitted with wire-mesh bases to allow detached ticks to fall through for collection. Southern African hedgehogs (Atelerix frontalis) were hand caught on a farm in the eastern region of the Northern Cape Province and all visible ticks were collected by means of tweezers while the animals were anaesthetised. The ticks from each animal were preserved separately in 70% ethanol for later identification and counting. The immature stages of five ixodid tick species were collected from the elephant shrews, of which Rhipicephalus muehlensi was the most common. It has not been recorded previously on any species of elephant shrew. Three ixodid tick species were collected from the hedgehogs. Large numbers of adult Haemaphysalis colesbergensis, which has not been encountered previously on hedgehogs, were collected from these animals. Four-toed elephant shrews are good hosts of the larvae and nymphs of R. muehlensi, and Southern African hedgehogs are good hosts of adult H. colesbergensis.

Sengi (Elephant-Shrew) Observations from Northern Coastal Kenya

The biodiversity of northern coastal Kenya is poorly understood because security problems and poor infrastructure have discouraged access to the area. However, the wooded areas in the region have great potential for harbouring unique and rare species, including sengis or elephant-shrews (Macroscelidea). Based on recent surveys of the Boni and Dodori National Reserves, which are between the Tana River and the Somali border, the ranges of the rufous sengi (Elephantulus rufescens) and four-toed sengi (Petrodromus tetradactylus) have been extended. Although the golden-ramped sengi (Rhynchocyon chrysopygus) of coastal Kenya south of the lower Tana River was assumed to occur in the Boni forest region, this now appears to be incorrect. The Rhynchocyon east of the lower Tana River is definitely not R. chrysopygus, but rather resembles taxa found hundreds of kilometres to the south. Determining the taxonomic status of what may be a new form of Rhynchocyon will require the collection of voucher specimens and DNA tissues for detailed analyses.

The Spatial Organization of the Four-Toed Elephant-Shrew (Petrodromus tetradactylus) in Tembe Elephant Park, KwaZulu-Natal, South Africa

Radio-tracking was undertaken over two months to investigate the social organization of the four-toed elephant-shrew (Petrodromus tetradactylus) in sand forest at Tembe Elephant Park, South Africa. Petrodromus tetradactylus occurred in monogamous male-female pairs that defended partially overlapping home ranges. There was virtually no overlap between the ranges of adjoining pairs, indicating low population density although not negating mutual avoidance or territorial defence, which could be inferred by incongruent intra-pair ranges. Our findings largely concur with those of a similar study of P. tetradactylus in Kenya and studies of other elephant-shrew species elsewhere. Home ranges estimated from a mean of >34 radio-tracking fixes over a short period suggest that male home range areas were similar to those reported in previous studies, while home range areas of females, although variable, were on average smaller than those previously reported. Most males and some females had two separate centres of activity that confounded the accurate estimation of their home ranges. The reason for this is unclear but may be related to habitat characteristics and quality, as it was not the result of home range shifts.

The topographic distribution of the penis and mammary glands in sengis (Macroscelidea) and its usefulness for taxonomic distinctions

The positions of the penis and nipples relative to the length and circumference of the body are investigated in each of the genera of Macroscelidea. The location of the penis is useful for the distinction between Macroscelides and Petrodromus, but not between any other genera of sengi, whereas nipple position is not useful in taxonomic distinctions among the four genera. Nipples were found on males in two species of sengi: Elephantulus rozeti and Petrodromus tetradactylus (but not on other species examined) supporting recent taxonomic conclusions regarding the relationship of these two taxa. No sengi exhibited nipples situated dorsolaterally to the extent of those in rock-dwelling mammals such as Petromus. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Use of space by the four-toed elephant-shrew Petrodromus tetradactylus (Macroscelidae) in Kwazulu-Natal (South Africa)

Four four-toed elephant-shrews Petrodromus tetradactylus were radio-tracked at Sodwana Bay National Park in the dune forest situated on sand-hills above the high water mark along the east coast of KwaZulu-Natal, South Africa. Tracking was conducted over 5 months during summer and the results were used to explore the use of space by the elephant-shrews. None of the topographical or vegetational features of the study area had any great influence on the distribution of the elephant-shrews. Both sexes occupied highly symmetrical (circular) home ranges that were similar in area. The elephant-shrews showed considerable fidelity to their home ranges, which had long-term permanence, but were not obviously defended as territories. Activity of the elephant-shrews, monitored for the first time during 24 h in the wild, was strongly crepuscular, with intense activity around dusk and dawn, much reduced during the day, with complete cessation of activity at night. There was considerable overlap between individual home ranges, suggesting a high population density. This may be related to the mild climate and ample food supply of the dune forest of northern KwaZulu-Natal or to the season of observation.

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.

Placenta and fetal membranes of the four-toed elephant shrew, Petrodromus tetradactylus

The four-toed elephant shrew is the only extant member of the genus Petrodromus. Some features of its placentation are found in other elephant shrews and may be important in consolidating the elephant shrews in the order Macroscelidea. These include implantation in an embryo chamber at the caudal end of the uterine horn; a large yolk sac; a large, lobulated allantoic sac; a distinct layer of proliferative trophoblastic cells between the labyrinthine and spongy zones of the placenta; an accessory epitheliochorial placenta; and the formation of a mesoplacenta by the decidua basalis. Of particular note are the large granulated cells that occupy the walls of decidual, myometrial and mesometrial arteries. They appear to be uterine natural killer cells. The persistence of a relatively large yolk sac and a large lobulated allantoic sac is a feature which Petrodromus and other elephant shrews share with other members of the superordinal clade Afrotheria.

Relative occupancy, endemism, taxonomic distinctiveness and vulnerability: prioritizing regional conservation actions

A method is presented whereby regional species are scored and ranked in order of regional conservation importance according to a number of different but complementary 'rarity' criteria. Approaches for determining regional occupancy (RO), relative taxonomic distinctiveness (RTD), relative endemism (RE) and relative vulnerability (RV) rankings for regional faunas are proposed. The continuous variable approach and resultant positively skewed 'rarity' scores suggest easy identification of regional priority species. These methods are collectively applied to a regional mammalian fauna in order to prioritize species for conservation action using a regional priority score (RPS). The proposed method is a comparative relational approach aimed at determining which species require the establishment of viable populations within a regional context. The two species afforded highest RPSs for the Transvaal region, South Africa, are Gunning's golden mole Amblysomus gunningi and Juliana's golden mole A. julianae. These two species are true endemics, with geographic ranges completely restricted to the region. Also of high regional conservation importance are the four-toed elephant shrew Petrodromus tetradactylus, pangolin Manis temminckii and aardvark Orycteropus afer. Although these species have low RE scores, they have high RTD and RV scores. The equal weightings given to the four components of 'rarity' ensures that species achieving a high score in any of these categories will be considered for regional priority listing. This approach is simple, explicit and repeatable, circumventing problems of scale.

The thermal biology of three southern African elephant-shrews

1. 1. The thermal characteristics of Petrodromus tetradactylus, Elephantulus intufi and E. brachyrhynchus were investigated and compared with other elephant-shrews that occur in the southern African subregion. 2. 2. E. intufi and E. brachyrhynchus appear to have lower than expected basal metabolic rates (1.1185 ± 0.1623 and 0.9649 ± 0.1638 ml O 2 g −1 h −1, respectively) and high, narrow thermoneutral zones, similar to other elephant-shrews investigated previously. In contrast P. tetradactylus has a basal metabolic rate (0.871 ± 0.027 ml O 2 g −1 h −1) close to expected for body mass, and a broad, low thermoneutral zone. 3. 3. The thermal biology of macroscelids is discussed in terms of their distribution, microhabitat and body size.

Subsistence Hunting in Arabuko-Sokoke Forest, Kenya, and Its Effects on Mammal Populations.

Mammal populations in Arabuko-Sokoke Forest, Kenya, provide an important source of protein and income for local communities. The harvested biomass in 1991 was over 350 kg/km2 , and the economic value of the harvest was over 1.3 million KShs (approximately US$35,000). Bushpigs, aardvarks, and primates comprise 95% of the harvested biomass, but the main prey in terms of number of animals killed (35% of total) was the four-toed elephant shrew (Petrodomus tetradactylus). Trapping is concentrated on the periphery of the forest and reduces densities of four-toed elephant shrews within 1-2 km of the forest edge by 41%, squirrels by 66%, and Syke's monkeys by 55%. Yellow baboons (Papio cynocephalus), Syke's monkeys (Cercopithecus mitis), and the larger ungulates are also hunted with dogs throughout the forest. The results of our study suggest that yellow baboons and Syke's monkeys are overharvested, and current offtake rates of elephant shrews, squirrels, and duikers (Cephalophus spp.) are sustainable. Overharvesting has reduced the densities of large ungulates, including bushbuck (Tragelaphus scriptus) and buffalo (Syncerus caffer), to low levels. Differences in reproductive rates, abundance, population, dispersion, ease of capture, and relative vulnerability to hunting, as compared to trapping, influence the extent to which different prey species are affected by harvesting. Caza de subsistencia en la selva de Arabuko-Sokoke, en Kenia, y sus efectos sobra las poblaciones de mamíferos.

Comparative ecology of two elephant‐shrew species in a Kenyan coastal forest

ABSTRACTThe Four‐toed Elephant‐Shrew Petrodromus tetradactylus is one of the most widely distributed elephant‐shrew species, ranging from Kenya to South Africa, while the Golden‐rumped Elephant Shrew Rhynchocyon chrysopygus has a limited distribution, being found only on the north Kenya coast. This paper compares the behaviour and ecology of the two species in Arabukc‐Sokoke Forest, Kenya. Compared with Four‐toed Elephant‐Shrews, Golden‐rumped Elephant‐Shrews have larger home ranges and maintain lower densities, as predicted from their greater body size. Both species prefer areas with dense vegetation cover, avoiding open areas, but the Four‐toed ElephantShrew shows a greater preference for dense thicket areas. Territory size was inversely correlated with dry‐season spider abundance in Golden‐rumped Elephant‐Shrews, and with dry‐season ant abundance in Four‐toed Elephant‐Shrews. Differences in activity patterns, as well as body size, may contribute to niche separation between the two species. Both species appear to be monogamous, with males and females defending overlapping territories. Male Golden‐rumped Elephant‐Shrews range over slightly larger areas than females, and are more likely to trespass into neighbouring territories. The less specific habitat requirements of Four‐toed Elephant‐Shrews and their higher densities are probably the two most important factors resulting in their wide distributional range.

Conservation issues and strategies for elephant‐shrews

ABSTRACTThe recommendations and implementation of the IUCN conservation plan for African Insectivora and elephant‐shrews (Nicoll & Rathbun, 1990) are reviewed. Of the 33 species and subspecies of elephant‐shrews, only six forest‐dwelling taxa are threatened. Until additional status data are gathered, assessed, and published no changes in the IUCN threatened categories should be made: Rhynchocyon chrysopygus is ‘vulnerable’; Rhynchocyon petersi petersi and Rhynchocyon petersi adersi are ‘rare’; and Rhynchocyon cirnei cirnei, Rhynchocyon cirnei hendersoni, and Petrodromus tetradactylus sangi are ‘insufficiently known’. Implementing status surveys that have not been completed, especially for the forms of R. petersi and P. t. sangi, are a high priority. Rhynchocyon petersi and R. chrysopygus densities are lower in altered and trapped forests compared with undisturbed forests. Because undisturbed forests in eastern Africa are highly fragmented, small, and disappearing due to human encroachment, it is important to determine the population dynamics of Rhynchocyon spp. that occupy degraded forest habitats, such as plantations, follow agricultural lands, and coastal scrub. In the face of the expanding human population, with its increasing need for land and natural resources, Rhynchocyon populations that occur in these degraded habitats may be all that remain in the future.

Biochemical systematics of elephant shrews from Southern Africa

Abstract The biochemical systematics of seven species of elephant shrews from southern Africa, based on allozyme variation and chromosomal analyses, was examined and compared to phylogenies based on morphological analyses. In addition, populations within three species, Elephantulus intufi , E. rupestris and E. myurus , were analysed for intrapopulational genetic variation. Both genetic and morphological data sets showed that all five species of Elephantulus examined were more closely related to each other than to either Petrodromus tetradactylus or Macroscelides proboscideus , but relationships within the Elephantulus differed among data sets. Genetic identify values indicated considerable divergence among species. Standard karyotypes showed 2 N = 30 for E. myurus , 2 N = 28 for P. tetradactylus and 2 N = 26 for the other five species. Levels of genetic heterozygosity ranged from 0.0 to 7.4%

Digestive tract dimensions and body mass of elephant shrews (Macroscelididae) and the effects of season and habitat

Macroscelidids have relatively short digestive tracts, consistent with their insectivorous diet. Compared with five species of Elephantulus, Macroscelides proboscideus had a relatively long large intestine and Petrodromus tetradactylus had a relatively short large intestine. These differences may reflect varying requirements for water conservation. E. myurus showed no seasonal changes in body weight but a significant reduction in the length of the small and large intestine in winter, the nonbreeding season.