Josef Bryja

Institute of Vertebrate Biology · Research Facility Studenec

Crocidura (Eulipotyphla, Soricidae) is the most species-rich genus among mammals, with high cryptic diversity and complicated taxonomy. The hirta-flavescens group of Crocidura represents the most abundant and widespread shrews in savannahs of eastern and southern Africa, making them a suitable phylogeographical model for assessing the role of paleo...

The extremely species-rich genus Trypanosoma has recently been divided into 16 subgenera, most of which show fairly high host specificity, including the subgenus Herpetosoma parasitizing mainly rodents. Although most Herpetosoma spp. are highly host-specific, the best-known representative, Trypanosoma lewisi, has a cosmopolitan distribution and low...

Considering climate change and high population increase, the conversion of natural habitats into arable land is rising at an alarming rate in the Ethiopian highlands. The impact on the diversity of rodents and shrews is difficult to measure since historical data are often unavailable. However, the relative effects of such land-use changes could be...

The Ethiopian highlands represent the largest part of the Eastern Afromontane Biodiversity Hotspot (EAMBH). Their fauna and flora are largely unique. Particularly, Afroalpine habitats on isolated mountains are known to harbour a large number of highly specialized endemic species. In contrast to intensively studied Afroalpine ecosystems, the forests...

The Kafa Biosphere Reserve (KBR) is the largest montane forest reserve in Ethiopia and was declared officially a United Nations Educational, Scientific and Cultural Organization (UNESCO) biosphere reserve in 2010. Only recently, however, has the reserve been surveyed in terms of its small- and medium-sized mammal inhabitant species. The KBR support...

The Livingstone Mountains (LM; also known as the Kipengere Range) found in southwestern Tanzania at the northern end of Lake Nyasa are an important region for understanding the biogeography of Eastern Africa. The two branches of the East African Rift Valley meet here and the mountains might represent stepping stones for colonization and migration b...

The Afar Triangle in easternmost Africa is one of biogeographically important regions, whose recent biota is virtually unknown. Here we evaluated the level of evolutionary uniqueness of biodiversity of this region in a wide regional and continental biogeograph-ical context, using rodents as a model group. By combining our recent collections with hi...

Mammarenaviruses have been a growing concern for public health in Africa since the 1970s when Lassa virus cases in humans were first described in west Africa. In southern Africa, a single outbreak of Lujo virus was reported to date in South Africa in 2008 with a case fatality rate of 80%. The natural reservoir of Lassa virus is Mastomys natalensis...

Aim Assessment of phylogenetic diversity and biogeographical affinities of the rodent fauna from one of the most neglected areas in Africa. Location Angola (with biogeographical implications in adjacent areas). Methods Inference of mitochondrial phylogenies for rodent genera occurring in Angola, delimitation of molecular operational taxonomic uni...

en Despite the importance of rodents as agricultural pests and reservoirs of zoonoses, the taxonomy and evolutionary history of many groups is still not sufficiently understood. The genus Mastomys (multimammate mice or rats) comprises abundant and intensively studied rodents, widespread across sub-Saharan Africa. Here, we used an extensive dataset...

African mole-rats (Bathyergidae) are an intensively studied family of subterranean rodents including three highly social and three solitary genera. Although their phylogenetic interrelations are clear, genetic diversity and the number of species within each genus is much less certain. Among the solitary genera, Heliophobius and Georychus were for a...

The tribe Praomyini is a diversified group including 64 species and eight extant rodent genera. They live in a broad spectrum of habitats across whole sub-Saharan Africa. Members of this tribe are often very abundant, they have a key ecological role in ecosystems, they are hosts of many potentially pathogenic microorganisms and comprise numerous ag...

In 2012, Tigray orthohantavirus was discovered in Ethiopia, but its seasonal infection in small mammals, and whether it poses a risk to humans was unknown. The occurrence of small mammals, rodents and shrews, in human inhabitations in northern Ethiopia is affected by season and presence of stone bunds. We sampled small mammals in two seasons from l...

Background: The speckled-pelage brush-furred rats (Lophuromys flavopunctatus group) have been difficult to define given conflicting genetic, morphological, and distributional records that combine to obscure meaningful accounts of its taxonomic diversity and evolution. In this study, we inferred the systematics, phylogeography, and evolutionary hist...

Hepatitis C virus (HCV; genus Hepacivirus) represents a major public health problem, infecting about 3% of the human population. Because no animal reservoir carrying closely related hepaciviruses has been identified, the zoonotic origins of HCV still remain unresolved. Motivated by recent findings of divergent hepaciviruses in rodents and a plausib...

The Ethiopian highlands represent a remarkable biodiversity “hotspot” with a very high number of endemic species, even among vertebrates. Ethiopian representatives of a species complex of speckled brush‐furred rats (Lophuromys flavopunctatus sensu lato) inhabit highland habitats ranging from low‐elevation forests to Afroalpine grasslands. These may...

The evolutionary history of sengis (Macroscelidea), an order of Afrotheria, has been studied in last decades by molecular phylogenetic approaches. These studies proposed an evolutionary scenario for this group of mammals and, surprisingly, revealed the presence of two new genera, delimited and described in the last five years. However, most researc...

Climbing mice in the genus Dendromus (sensu lato) are widely distributed in Africa, south of the Saharan Desert. The 17 currently recognized species in the genus range from widespread taxa to single-mountain endemics, and there is considerable variation across species with respect to habitats occupied. These habitats range from arid grasslands and...

Background: The speckled-pelage brush-furred rats (Lophuromys flavopunctatus group) has been difficult to define given conflicting genetic, morphological, and distributional records that combine to obscure meaningful accounts of its taxonomic diversity. In this study, we inferred the systematics, phylogeography, and evolutionary history of the L. f...

The tribe Arvicanthini (Muridae: Murinae) is a highly diversified group of rodents (ca. 100 species) and with 18 African genera (plus one Asiatic) represents probably the most successful adaptive radiation of extant mammals in Africa. They colonized a broad spectrum of habitats (from rainforests to semi-deserts) in whole sub-Saharan Africa and thei...

Organisms living in high altitude must adapt to environmental conditions with hypoxia and low temperature, e.g. by changes in the structure and function of proteins associated with oxidative phosphorylation in mitochondria. Here we analysed the signs of adaptive evolution in 27 mitogenomes of endemic Ethiopian rats (Stenocephalemys), where individu...

We describe two new species of white-toothed shrews from south-western and central Ethiopia, based on recent collections and an application of morphological and genetic methods, Crocidura similiturba sp. nov. and Crocidura makeda sp. nov. Comparisons are provided with other Crocidura species known to occur in the country. Both new species are curre...

Murine rodents are one of the most evolutionary successful groups of extant mammals. They are also important for human as vectors and reservoirs of zoonoses and agricultural pests. Unfortunately, their fast and relatively recent diversification impedes our understanding of phylogenetic relationships and species limits of many mu-rine taxa, includin...

Hepatitis C virus (HCV; genus Hepacivirus) represents a major public health problem, infecting about 3 % of the human population (± 185,000,000 people). Because no plausible animal reservoir carrying closely related hepaciviruses has been identified, the zoonotic origins of HCV still remain elusive. Motivated by recent findings of divergent hep-aci...

Ethiopian rats (genus Stenocephalemys) represent a monophyletic group of Ethiopian endemic rodents that diverged in the Ethiopian Highlands during the Pleistocene. Because of the frequent occurrence of so-called reticulate evolution (i.e. repeated hybridization of partially diverged populations), their taxonomy has not been adequately resolved, des...

Mastomys natalensis is widespread in sub-Saharan Africa and hosts several arenavirus species, including the pathogenic zoonotic Lassa virus in West Africa. Mitochondrial lineages sub-divide the range of M. natalensis and have been associated with cryptic structure within the species. To test specificity of arenaviruses to hosts carrying these linea...

Faunal studies of rodent assemblages from the areas on and around Choke Mountain (north-western Ethiopia) were conducted during two field seasons in 2012 and 2018. Here we present results of a genetic study of nine rodent species, and evaluate their genetic diversity and evolutionary relationships between conspecific populations from neighbouring m...

Key adaptations enabling mammals to cope with oxygen deficiency at high elevations relate to oxygen transfer into the blood. Among others, the efficiency of this mechanism depends on haematocrit (Hct, the volumetric fraction of red blood cells in blood). Although blood of high-elevation mammals is usually characterised by normal or slightly increas...

The 13th African Small Mammal Symposium (ASMS) was organized on September 16-21, 2019, at Mekelle University in Mekelle, Tigray, Ethiopia. Starting in 1977, these symposia are organized every four years and since 2003 have been held in tropical Africa. The aim of the meetings is to promote communication among researchers and students interested in...

Climatic data, including mean ± standard deviation, range, and sample size of days measured (number of days receiving rainfall in parentheses) for each site sampled between September and November 2015 in Simien Mountains National Park, Ethiopia.

Field guide with representative photos of select small mammal species in Simien Mountains National Park, Ethiopia. Species 1–11 were sampled during our 2015 survey.

Despite the presence of mostly endemic species, the most comprehensive data set on the distribution and ecology of small mammals inhabiting Simien Mountains National Park (SMNP) dated from 1927. The study we carried out and report here provides a unique opportunity to assess the possible role of climate change over the last 88 years on the elevatio...

Multimammate mice of the genus Mastomys are widespread in sub-Saharan Africa and occur in a wide range of open habitats. Representatives of this genus are the most common African rodents, the main vertebrate agricultural pests and vectors of human pathogens. In Ethiopia, the biogeographically most complex eastern African country, several species ha...

As in many other small mammal groups from the Afrotropics, the number of species recognized within the genus Hylomyscus has increased considerably over the past dozen years. The last comprehensive review (2005) of the genus recognized eight species. Since that time, nine additional species have been elevated from synonymy (n = 4) or described as ne...

The murid rodent Praomys daltoni is widespread in Sudanian savanna and woodlands of West Africa, and previous study of mitochondrial DNA variability suggested that it encompasses the phenotypically (small, grey-bellied) and ecologically (commensal) distinct form, Praomys derooi. Here, we comprehensively examined the genetic and morphological divers...

Wood mice of the genus Hylomyscus, are small-sized rodents widely distributed in lowland and montane rainforests in tropical Africa, where they can be locally abundant. Recent morphological and molecular studies have increased the number of recognized species from 8 to 18 during the last 15 years. We used complete mitochondrial genomes and five nuc...

Little is known about the distribution and ecology of small mammals inhabiting Simien Mountains National Park despite the presence of mostly endemic species. Prior to this study, the most comprehensive dataset was collected in 1927. This provides a unique opportunity to assess the possible role of climate change over the last 88 years on the elevat...

We provide an annotated checklist of rodents of Ethiopia. For each species we show a distributional map based on critically revised data from: (1) published literature; (2) museum collections, including records in the Global Biodiversity Information Facility (GBIF); and (3) recent field surveys performed in the last three decades as part of the Joi...

Orthohantaviruses are RNA viruses that some members are known to cause severe zoonotic diseases in humans. Orthohantaviruses are hosted by rodents, soricomorphs (shrews and moles), and bats. Only two orthohantaviruses associated with murid rodents are known in Africa, Sangassou orthohantavirus (SANGV) in two species of African wood mice (Hylomyscus...

Aim We investigate the Plio‐Pleistocene evolutionary history of one of the most abundant rodents in Afrotropical forests. Specifically, we ask how their diversification was influenced by climate change, topography and major rivers. Location Tropical Africa: Lower Guinea (including Cameroon volcanic line; CVL), Congolia, Albertine Rift (AR), Kenyan...

African Grass Rats of the genus Arvicanthis Lesson, 1842, are one of the most important groups of rodents in sub‐Saharan Africa. They are abundant in a variety of open habitats, they are major agricultural pests, and they became a popular model in physiological research because of their diurnal activity. Despite this importance, information about t...

Background: Spiny mice of the genus Acomys are distributed mainly in dry open habitats in Africa and the Middle East, and they are widely used as model taxa for various biological disciplines (e.g. ecology, physiology and evolutionary biology). Despite their importance, large distribution and abundance in local communities, the phylogeny and the s...

Background Anthropogenic factors can have a major impact on the contemporary distribution of intraspecific genetic diversity. Many freshwater fishes have finely structured and locally adapted populations, but their natural genetic structure can be affected by river engineering schemes across river basins, fish transfers in aquaculture industry and...

South-east Europe, along with the adjacent region of south-west Asia, is an important biodiversity hotspot with high local endemism largely contributed by contemporary continental lineages that retreated to southern refugia during colder Quaternary periods. We investigated the genetic diversity of the European bitterling fish (Rhodeus amarus) speci...

Even though populations of many large carnivores are expanding throughout Europe, the Eurasian lynx population in the Western Carpathians seems unable to spread beyond the western boundaries of its current distributional range. Many factors, both extrinsic and intrinsic, can influence the potential for range expansion: landscape fragmentation, nata...

Murid rodents (Rodentia: Muridae) represent the most diverse and abundant mammalian family. In this study, we provide a refined set of fossil calibrations which is used to reconstruct a dated phylogeny of the family using a multilocus dataset (six nuclear and nine mitochondrial gene fragments) encompassing 161 species representing 82 murid genera f...

The Arsi Mountains (Southeastern Ethiopian mountain block) are a unique region comprising a range of habitats, including natural montane forest, extensive eri-caceous scrub and small, restricted patches of Afroalpine ecosystem. During 3 years of sampling small mammals, 13 rodent species were recorded, including the extremely rare Mus imberbis and D...

The silvery mole-rat (Heliophobius argenteocinereus) is a solitary subterranean rodent with its distribution centred mainly in miombo woodlands of eastern Africa. This part of the continent was significantly influenced by the formation of the East African Rift System (EARS) during the last 25 Mya and by pronounced climatic changes in the Plio-Pleis...

Understanding the invasive potential of species outside their native range is one of the most pressing questions in applied evolutionary and ecological research. Admixture of genotypes of invasive species from multiple sources has been implicated in successful invasions, by generating novel genetic combinations that facilitate rapid adaptation to n...

Dated phylogeny for family Muridae.

Positive selection acting on Toll‐like receptors (TLRs) has been recently investigated to reveal evolutionary mechanisms of host‐pathogen molecular co‐adaptation. Much of this research, however, has focused mainly on the identification of sites predicted to be under positive selection, bringing little insight into the functional differences and sim...

African Small Mammals Symposium, September 2019. Mekelle University, Mekelle, Ethiopia

Field Guide

Small Mammal Field Guide: Simien Mountains National Park, Ethiopia

Despite the high degree of biological diversity in the Zambezian region, little information is available regarding the evolutionary history of its biota, and this is especially true for the fauna and flora of non-forested habitats. Here we use the most comprehensive multi-locus genetic dataset available to (1) reconstruct the phylogeny of spiny mic...

Small terrestrial mammals and their biogeographical affinities were studied on Mount Kitumbeine, one of the little known volcanoes in the Gregory Rift Valley (northern Tanzania). In June, 2015, a total of 10 species, two insectivores and eight rodents, were recorded during a short-time sampling in two high altitude habitats. Taxonomic identificatio...