Abstract Multi‐mammate rats (Muridae, Murinae, Mastomys spp.) are Sub‐Saharan pest rodents, the systematics of which has long remained confused due to poor morphologic differentiation. Cytotaxonomy and DNA sequencing have provided excellent diagnostic markers for species identification, thus improving the assessment of taxonomic diversity within the genus. In West and Central Africa, three species have been unambiguously identified and are now well documented: Mastomys erythroleucus, Mastomys natalensis and Mastomys huberti . However, recent studies suggest the existence of two other taxa on the basis of morphology, DNA sequencing ( Mastomys verheyeni , from Nigeria and Northern Cameroon) or karyotypes ( Mastomys cf. kollmannspergeri , from Northern Niger and Chad). In order to clarify the systematic status of the latter taxa, we collected all the available cytotaxonomic as well as cytochrome b sequencing data to which were added results obtained from recently trapped specimens in Northern Cameroon. Our combined molecular and cytogenetic analyses unambiguously confirm the presence of another Mastomys species inhabiting various habitats in Niger, Nigeria, Cameroon, Chad and Sudan. This taxon is clearly differentiated from M. erythroleucus, M. huberti and M. natalensis . Furthermore, the inclusion in our analysis of two M. verheyeni paratypes as well as individuals trapped in close vicinity to the type locality of M. kollmannspergeri supports the assignation of all specimens to M. kollmanspergeri , thus making M. verheyeni its junior synonym. Our study once again highlights the reliability of DNA‐ and karyotype‐based methods to accurately assess specific diversity in African rodents, particularly in the Mastomys genus, which shelters several species of agricultural and epidemiological importance.

Mastomys

Cytotaxonomy

Muridae

Synapomorphy

10.1111/j.1469-7998.2008.00500.x

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Citations (35)

Polymorphism of the age population structure of two wild Mastomys natalensis (Rodentia: Muridae) Tanzanian habitat samples: a multicriteria comparison / Polymorphisme de la structure de l'âge dans deux populations sauvages de Mastomys natalensis (Rodentia: Muridae) de Tanzanie: une comparaison sur la base de plusieurs critères d'étude

Mammalia (2006)

Aude Lalis Émilie Lecompte Raphaël Cornette Sybille Moulin Robert S. Machang’u

To study the age structure of two different samples of Mastomys natalensis during a dry period, we use three different approaches: body weight, tooth wear and eye lens weight. According to each of these techniques, our samples are made up principally of young individuals. Fisher's exact test of significance shows that gender does not appear to be a significant variable between the two samples. These results are consistent with the population cycling of this species and confirm its important dispersion potential. Moreover, in the low rainfall context of winter 2003, our data suggest age differences between the two samples from different habitats. In this study, the variable best correlated with age was eye lens weight for the first age class. The body weight method seems the best adapted to the sampling conditions (small sample size, reproduction period) and its objectives (instantaneous age determination of samples). This study shows that even with limited data sets, some simple precautions during manipulation and a clear understanding of methodological limits provide informative results. If combined with detailed morphological descriptions and molecular variation, these results should give new insights into differentiation processes and models for M. natalensis.

Mastomys

Muridae

10.1515/mamm.2006.052

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Citations (8)

The antique genetic plight of the Mediterranean monk seal (Monachus monachus)

bioRxiv (Cold Spring Harbor Laboratory) (2021)

Jordi Salmona Julia Dayon Émilie Lecompte Alexandros A. Karamanlidis Àlex Aguilar

Abstract Disentangling the impact of Late Quaternary climate change from human activities can have crucial implications on the conservation of endangered species. We investigated the population genetics and demography of the Mediterranean monk seal ( Monachus monachus ), one of the world’s most endangered marine mammals, through an unprecedented dataset encompassing historical (extinct) and extant populations from the eastern North Atlantic to the entire Mediterranean Basin. We show that Cabo Blanco (Western Sahara/Mauritania), Madeira, Western Mediterranean (historical range), and Eastern Mediterranean regions segregate into four populations. This structure is likely the consequence of recent drift, combined with long-term isolation by distance ( R 2 = 0.7), resulting from prevailing short-distance (< 500 km) and infrequent long-distance dispersal (< 1,500 km). All populations (Madeira especially), show high levels of inbreeding and low levels of genetic diversity, seemingly declining since historical time, but surprisingly not being impacted by the 1997 massive die-off in Cabo Blanco. Approximate Bayesian Computation analyses support scenarios combining local extinctions and a major effective population size decline in all populations during Antiquity. Our results suggest that the early densification of human populations around the Mediterranean Basin coupled with the development of seafaring techniques were the main drivers of the decline of Mediterranean monk seals.

Mediterranean Basin

Mediterranean Islands

10.1101/2021.12.23.473149

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Citations (1)

Fluctuation of Abundance and Lassa Virus Prevalence in Mastomys natalensis in Guinea, West Africa

Vector-Borne and Zoonotic Diseases (2007)

Elisabeth Fichet‐Calvet Émilie Lecompte Lamine Koivogui Barré Soropogui Amadou Doré

Based on empiric surveillance data, the incidence of human Lassa fever (LF) cases in Guinea and other West African countries has been reported to increase during the dry season compared to the rainy season. To investigate possible links with the ecology of the rodent reservoir of the virus, we conducted a 2-year longitudinal survey of Mastomys natalensis in a region of high human Lassa virus (LASV) seropositivity in Guinea. Standardized rodent trapping with similar trapping efforts between seasons was performed in three villages and 53.5% (601/1123) of the animals were identified as M. natalensis using morphometric and molecular criteria. Mean trapping success (TS) of M. natalensis was always higher inside houses than in proximal cultivations. In the dry season, mean TS increased 2-fold inside houses and decreased up to 10-fold outside (p < 0.0001), suggesting aggregation of rodents inside houses due to restricted food supply. 14.5% (80/553) of M. natalensis were tested positive for Lassa virus by reverse transcription-polymerase chain reaction (RT-PCR; range, 5%–30%) and prevalence of the virus was two to three times higher in rodents captured in the rainy season than in the dry season (p < 0.05). Inside houses, however, the LASV prevalence fluctuated nonsignificantly with season. These data suggest that in Guinea the risk of LASV transmission from rodents to humans is present both in the rainy and the dry season, reflected by the occurrence of LF cases throughout the year. In the dry season, however, the increased risk of humans encountering Mastomys and their excreta inside of houses may result in an increase of human Lassa fever cases. Vector-Borne Zoonotic Dis. 7, 119–128.

Mastomys

Lassa fever

Dry season

Wet season

Lassa virus

Arenavirus

10.1089/vbz.2006.0520

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Citations (130)

Phylogeny and historical demography of economically important rodents of the genus Arvicanthis (Mammalia: Muridae) from the Nile Valley: of mice and men

Biological Journal of the Linnean Society (2008)

E. H. ABDEL RAHMAN AHMED J.-F. Ducroz Andrew Mitchell Jennifer Lamb G. Contrafatto

The present study clarified the taxonomy, phylogeny and historical demography of semicommensal Nile rats (Arvicanthis) from the Nile Valley in Sudan. Nile rats are important crop pests and zoonotic disease reservoirs and are closely associated with agricultural settlements in the Nile Valley. Phylogenetic analysis of the complete cytochrome b gene (1140 bp) of 23 individuals from six localities in Sudan (from two previously recognized species, Arvicanthis niloticus and Arvicanthis testicularis), supported the existence of only a single species, A. niloticus, from the Nile Valley. Historical demography of the Sudanese Nile Valley population inferred from mismatch coefficients indicated that an exponential population expansion event occurred approximately 144 000–288 000 years ago, corresponding in time with early human expansion and colonization from Africa to the Middle East, Europe, and the world. The inferred high level of gene flow and large size of Sudanese Nile populations of A. niloticus is consistent with historically recent (300 years ago) exponential human population growth and intense agricultural activity inferred from archaeological and historical evidence. Two African Arvicanthis clades were well supported by the broader phylogenetic analysis: (1) A. niloticus, Arvicanthis abyssinicus and Arvicanthis neumanni and (2) Arvicanthis rufinus and Arvicanthis ansorgei from western Africa. Within the first clade, divergence between lineages of A. niloticus s.s. from west and north-east Africa (8.9%) suggests specific recognition, but sampling of geographically intermediate localities is required. Based on hypothesized palaeodrainage and palaeoclimatic patterns, we propose a simple model for speciation of Arvicanthis in Africa.

10.1111/j.1095-8312.2007.00895.x

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Citations (17)

First case of parthenogenesis in ladybirds (Coleoptera: Coccinellidae) suggests new mechanisms for the evolution of asexual reproduction

Journal of Zoological Systematics & Evolutionary Research (2019)

Alexandra Magro Émilie Lecompte Jean‐Louis Hemptinne António O. Soares Anne‐Marie Dutrillaux

Parthenogenesis, the development of unfertilized eggs resulting in the exclusive production of female offspring, is rare in animals relative to sexual reproduction and is mainly reported in invertebrates. It has been hypothesized that polyploidy, hybridization and endosymbiont infections are its major causal events but the mechanisms triggering asexual reproduction remain unclear. Here, we study the proximate causes at the origin of parthenogenesis in the first reported case of asexuality in the Coccinellidae (Coleoptera). The asexual populations were found in the Azores and the Mascarene archipelagos, and were identified as Nephus voeltzkowi Weise, a bisexual species widespread in sub-Saharan Africa. The specimens from both populations are diploid but present different karyotypes and heterozygosities that evoke hybrid origins, commonly associated with parthenogenesis in Coleoptera. However, the close proximity of their genomes (99.8% homology for the complete mitochondrial genome and 99.9% for the complete nuclear ribosomal cluster) together with the congruence between the mtDNA tree and the nuclear tree, and the low heterozygosity levels, suggests that the two populations are not hybrid. We propose that they belong to a single chromosomally polymorphic species undergoing Robertsonian fusions. Furthermore, specimens from both populations are infected with Wolbachia (supergroup B strain), contrary to sympatric bisexual species of the same genus. Although Wolbachia has been shown to induce parthenogenesis in haplodiploid organisms, it has been recently suggested that it could also induce parthenogenesis in hosts with other sex determination systems. Whether chromosome rearrangements and/or Wolbachia infections are post-parthenogenetic events or are at the origin of parthenogenesis still needs to be determined.

Parthenogenesis

Asexuality

Asexual reproduction

10.1111/jzs.12339

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Citations (15)