Phylogeography of African fruitbats (Megachiroptera)

Interrogating Phylogenetic Discordance Resolves Deep Splits in the Rapid Radiation of Old World Fruit Bats (Chiroptera: Pteropodidae)

The family Pteropodidae (Old World fruit bats) comprises $>$200 species distributed across the Old World tropics and subtropics. Most pteropodids feed on fruit, suggesting an early origin of frugivory, although several lineages have shifted to nectar-based diets. Pteropodids are of exceptional conservation concern with $>$50% of species considered threatened, yet the systematics of this group has long been debated, with uncertainty surrounding early splits attributed to an ancient rapid diversification. Resolving the relationships among the main pteropodid lineages is essential if we are to fully understand their evolutionary distinctiveness, and the extent to which these bats have transitioned to nectar-feeding. Here we generated orthologous sequences for $>$1400 nuclear protein-coding genes (2.8 million base pairs) across 114 species from 43 genera of Old World fruit bats (57% and 96% of extant species- and genus-level diversity, respectively), and combined phylogenomic inference with filtering by information content to resolve systematic relationships among the major lineages. Concatenation and coalescent-based methods recovered three distinct backbone topologies that were not able to be reconciled by filtering via phylogenetic information content. Concordance analysis and gene genealogy interrogation show that one topology is consistently the best supported, and that observed phylogenetic conflicts arise from both gene tree error and deep incomplete lineage sorting. In addition to resolving long-standing inconsistencies in the reported relationships among major lineages, we show that Old World fruit bats have likely undergone at least seven independent dietary transitions from frugivory to nectarivory. Finally, we use this phylogeny to identify and describe one new genus. [Chiroptera; coalescence; concordance; incomplete lineage sorting; nectar feeder; species tree; target enrichment.].

Isolation of a Novel Bat Rhabdovirus with Evidence of Human Exposure in China

Bats are well-recognized reservoirs of zoonotic viruses. Several spillover events from bats to humans have been reported, causing severe epidemic or endemic diseases including severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), SARS-CoV, Middle East respiratory syndrome-CoV (MERS-CoV), henipaviruses, and filoviruses. In this study, a novel rhabdovirus species, provisionally named Rhinolophus rhabdovirus DPuer (DPRV), was identified from the horseshoe bat (Rhinolophus affinis) in Yunnan province, China, using next-generation sequencing. DPRV shedding in the spleen, liver, lung, and intestinal contents of wild bats with high viral loads was detected by real-time quantitative PCR, indicating that DPRV has tropism for multiple host tissues. Furthermore, DPRV can replicate in vitro in multiple mammalian cell lines, including BHK-21, A549, and MA104 cells, with the highest efficiency in hamster kidney cell line BHK-21, suggesting infectivity of DPRV in these cell line-derived hosts. Ultrastructure analysis revealed a characteristic bullet-shaped morphology and tightly clustered distribution of DPRV particles in the intracellular space. DPRV replicated efficiently in suckling mouse brains and caused death of suckling mice; death rates increased with passaging of DPRV in suckling mice. Moreover, 421 serum samples were collected from individuals who lived near the bat collection site and had fever symptoms within 1 year. DPRV-specific antibodies were detected in 20 (4.75%) human serum samples by indirect immunofluorescence assay. Furthermore, 10 (2.38%) serum samples were DPRV positive according to plaque reduction neutralization assay, which revealed potential transmission of DPRV from bats to humans and highlighted the potential public health risk. Potential vector association with DPRV was not found with negative viral RNA in bloodsucking arthropods. IMPORTANCE We identified a novel rhabdovirus from the horseshoe bat (Rhinolophus thomasi) in China with probable infectivity in humans. DPRV was isolated in vitro from several mammalian cell lines, indicating wide host tropism, excluding bats, of DPRV. DPRV replicated in the brains of suckling mice, and the death rate of suckling mice increased with passaging of DPRV in vivo. Serological tests indicated the possible infectivity of DPRV in humans and the potential transmission to humans. The present findings provide preliminary evidence for the potential risk of DPRV to public health. Additional studies with active surveillance are needed to address interspecies transmission and determine the pathogenicity of DPRV in humans.

The Gambian epauletted fruit bat shows increased genetic divergence in the Ethiopian highlands and in an area of rapid urbanization

The Gambian epauletted fruit bat (Epomophorus gambianus) is an abundant species that roosts in both urban and rural settings. The possible role of E. gambianus as a reservoir host of zoonotic diseases underlines the need to better understand the species movement patterns. So far, neither observational nor phylogenetic studies have identified the dispersal range or behavior of this species. Comparative analyses of mitochondrial and nuclear markers from 20 localities across the known distribution of E. gambianus showed population panmixia, except for the populations in Ethiopia and southern Ghana (Accra and Ve-Golokwati). The Ethiopian population may be ancestral and is highly divergent to the species across the rest of its range, possibly reflecting isolation of an ancient colonization along an east-west axis. Mitochondrial haplotypes in the Accra population display a strong signature of a past bottleneck event; evidence of either an ancient or recent bottleneck using microsatellite data, however, was not detected. Demographic analyses identified population expansion in most of the colonies, except in the female line of descent in the Accra population. The molecular analyses of the colonies from Ethiopia and southern Ghana show gender dispersal bias, with the mitochondrial DNA fixation values over ten times those of the nuclear markers. These findings indicate free mixing of the species across great distances, which should inform future epidemiological studies.

Phylogenetic and geographic patterns of bartonella host shifts among bat species

The influence of factors contributing to parasite diversity in individual hosts and communities are increasingly studied, but there has been less focus on the dominant processes leading to parasite diversification. Using bartonella infections in bats as a model system, we explored the influence of three processes that can contribute to bartonella diversification and lineage formation: (1) spatial correlation in the invasion and transmission of bartonella among bats (phylogeography); (2) divergent adaptation of bartonellae to bat hosts and arthropod vectors; and (3) evolutionary codivergence between bats and bartonellae. Using a combination of global fit techniques and ancestral state reconstruction, we found that codivergence appears to be the dominant process leading to diversification of bartonella in bats, with lineages of bartonellae corresponding to separate bat suborders, superfamilies, and families. Furthermore, we estimated the rates at which bartonellae shift bat hosts across taxonomic scales (suborders, superfamilies, and families) and found that transition rates decrease with increasing taxonomic distance, providing support for a mechanism that can contribute to the observed evolutionary congruence between bats and their associated bartonellae. While bartonella diversification is associated with host sympatry, the influence of this factor is minor compared to the influence of codivergence and there is a clear indication that some bartonella lineages span multiple regions, particularly between Africa and Southeast Asia. Divergent adaptation of bartonellae to bat hosts and arthropod vectors is apparent and can dilute the overall pattern of codivergence, however its importance in the formation of Bartonella lineages in bats is small relative to codivergence. We argue that exploring all three of these processes yields a more complete understanding of bat-bartonella relationships and the evolution of the genus Bartonella, generally. Application of these methods to other infectious bacteria and viruses could uncover common processes that lead to parasite diversification and the formation of host-parasite relationships.

Bat trait, genetic and pathogen data from large-scale investigations of African fruit bats, Eidolon helvum

Bats, including African straw-coloured fruit bats (Eidolon helvum), have been highlighted as reservoirs of many recently emerged zoonotic viruses. This common, widespread and ecologically important species was the focus of longitudinal and continent-wide studies of the epidemiological and ecology of Lagos bat virus, henipaviruses and Achimota viruses. Here we present a spatial, morphological, demographic, genetic and serological dataset encompassing 2827 bats from nine countries over an 8-year period. Genetic data comprises cytochrome b mitochondrial sequences (n=608) and microsatellite genotypes from 18 loci (n=544). Tooth-cementum analyses (n=316) allowed derivation of rare age-specific serologic data for a lyssavirus, a henipavirus and two rubulaviruses. This dataset contributes a substantial volume of data on the ecology of E. helvum and its viruses and will be valuable for a wide range of studies, including viral transmission dynamic modelling in age-structured populations, investigation of seasonal reproductive asynchrony in wide-ranging species, ecological niche modelling, inference of island colonisation history, exploration of relationships between island and body size, and various spatial analyses of demographic, morphometric or serological data.

Novel paramyxoviruses in Australian flying-fox populations support host-virus co-evolution

Understanding the diversity of henipaviruses and related viruses is important in determining the viral ecology within flying-fox populations and assessing the potential threat posed by these agents. This study sought to identify the abundance and diversity of previously unknown paramyxoviruses (UPVs) in Australian flying-fox species (Pteropus alecto, Pteropus scapulatus, Pteropus poliocephalus and Pteropus conspicillatus) and in the Christmas Island species Pteropus melanotus natalis. Using a degenerative reverse transcription-PCR specific for the L gene of known species of the genus Henipavirus and two closely related paramyxovirus genera Respirovirus and Morbillivirus, we identified an abundance and diversity of previously UPVs, with a representative 31 UPVs clustering in eight distinct groups (100 UPVs/495 samples). No new henipaviruses were identified. The findings were consistent with a hypothesis of co-evolution of paramyxoviruses and their flying-fox hosts. Quantification of the degree of co-speciation between host and virus (beyond the scope of this study) would strengthen this hypothesis.

Continent-wide panmixia of an African fruit bat facilitates transmission of potentially zoonotic viruses

The straw-coloured fruit bat, Eidolon helvum, is Africa’s most widely distributed and commonly hunted fruit bat, often living in close proximity to human populations. This species has been identified as a reservoir of potentially zoonotic viruses, but uncertainties remain regarding viral transmission dynamics and mechanisms of persistence. Here we combine genetic and serological analyses of populations across Africa, to determine the extent of epidemiological connectivity among E. helvum populations. Multiple markers reveal panmixia across the continental range, at a greater geographical scale than previously recorded for any other mammal, whereas populations on remote islands were genetically distinct. Multiple serological assays reveal antibodies to henipaviruses and Lagos bat virus in all locations, including small isolated island populations, indicating that factors other than population size and connectivity may be responsible for viral persistence. Our findings have potentially important public health implications, and highlight a need to avoid disturbances which may precipitate viral spillover.

Environmental margin and island evolution in Middle Eastern populations of the Egyptian fruit bat

Here, we present a study of the population genetic architecture and microevolution of the Egyptian fruit bat (Rousettus aegyptiacus) at the environmental margins in the Middle East using mitochondrial sequences and nuclear microsatellites. In contrast to the rather homogenous population structure typical of cave-dwelling bats in climax tropical ecosystems, a relatively pronounced isolation by distance and population diversification was observed. The evolution of this pattern could be ascribed to the complicated demographic history at higher latitudes related to the range margin fragmentation and complex geomorphology of the studied area. Lineages from East Africa and Arabia show divergent positions. Within the northwestern unit, the most marked pattern of the microsatellite data set is connected with insularity, as demonstrated by the separate status of populations from Saharan oases and Cyprus. These demes also exhibit a reduction in genetic variability, which is presumably connected with founder effects, drift and other potential factors related to island evolution as site-specific selection. Genetic clustering indicates a semipermeability of the desert barriers in the Sahara and Arabian Peninsula and a corridor role of the Nile Valley. The results emphasize the role of the island environment in restricting the gene flow in megabats, which is also corroborated by biogeographic patterns within the family, and suggests the possibility of nascent island speciation on Cyprus. Demographic analyses suggest that the colonization of the region was connected to the spread of agricultural plants; therefore, the peripatric processes described above might be because of or strengthened by anthropogenic changes in the environment.

Evolutionary relationships of the old world fruit bats (Chiroptera, Pteropodidae): another star phylogeny?

BACKGROUND

The family Pteropodidae comprises bats commonly known as megabats or Old World fruit bats. Molecular phylogenetic studies of pteropodids have provided considerable insight into intrafamilial relationships, but these studies have included only a fraction of the extant diversity (a maximum of 26 out of the 46 currently recognized genera) and have failed to resolve deep relationships among internal clades. Here we readdress the systematics of pteropodids by applying a strategy to try to resolve ancient relationships within Pteropodidae, while providing further insight into subgroup membership, by 1) increasing the taxonomic sample to 42 genera; 2) increasing the number of characters (to >8,000 bp) and nuclear genomic representation; 3) minimizing missing data; 4) controlling for sequence bias; and 5) using appropriate data partitioning and models of sequence evolution.

RESULTS

Our analyses recovered six principal clades and one additional independent lineage (consisting of a single genus) within Pteropodidae. Reciprocal monophyly of these groups was highly supported and generally congruent among the different methods and datasets used. Likewise, most relationships within these principal clades were well resolved and statistically supported. Relationships among the 7 principal groups, however, were poorly supported in all analyses. This result could not be explained by any detectable systematic bias in the data or incongruence among loci. The SOWH test confirmed that basal branches' lengths were not different from zero, which points to closely-spaced cladogenesis as the most likely explanation for the poor resolution of the deep pteropodid relationships. Simulations suggest that an increase in the amount of sequence data is likely to solve this problem.

CONCLUSIONS

The phylogenetic hypothesis generated here provides a robust framework for a revised cladistic classification of Pteropodidae into subfamilies and tribes and will greatly contribute to the understanding of character evolution and biogeography of pteropodids. The inability of our data to resolve the deepest relationships of the major pteropodid lineages suggests an explosive diversification soon after origin of the crown pteropodids. Several characteristics of pteropodids are consistent with this conclusion, including high species diversity, great morphological diversity, and presence of key innovations in relation to their sister group.

Phylogeny and biogeography of western Indian Ocean Rousettus (Chiroptera: Pteropodidae)

We examined patterns of genetic variation in Rousettus madagascariensis from Madagascar and R. obliviosus from the Comoros (Grande Comore, Anjouan, and Mohéli). Genetic distances among individuals on the basis of 1,130 base pairs of the mitochondrial cytochrome b (Cytb) locus were estimated from specimens collected from 17 sites on Madagascar, 3 sites on Grande Comore, 3 sites on Anjouan, and 2 sites on Mohéli. We observed little variation in Madagascar and nearshore island samples (maximum 1.1%) and interisland Comoros samples (maximum 1.8%). In contrast, pairwise distances between different sampled sites on Madagascar and the Comoros varied from 8.5% to 13.2%. For 131 Malagasy animals, 69 unique haplotypes were recovered with 86 variable sites, and for 44 Comorian individuals, 17 unique haplotypes were found with 30 variable sites. No haplotype was shared between Madagascar and the Comoros, adding to previous morphological evidence that these 2 populations should be considered separate species. Cytb data showed that Rousettus populations of Madagascar (including nearshore islands) and the Comoros are respectively monophyletic and display no geographic structure in haplotype diversity, and that R. madagascariensis and R. obliviosus are strongly supported as sister to each other relative to other Rousettus species. Genotypic data from 6 microsatellite loci confirm lack of geographic structure in either of the 2 species. In pairwise tests of population differentiation, the only significant values were between samples from the Comoro Islands and Madagascar (including nearshore islands). Estimates of current and historical demographic parameters support population expansion in both the Comoros and Madagascar. These data suggest a more recent and rapid demographic expansion in Madagascar in comparison with greater population stability on the Comoros. On the basis of available evidence, open-water crossings approaching 300 km seem rarely traversed by Rousettus, and, if successful, can result in genetic isolation and subsequent differentiation.

The phylogenetic relationships of cynopterine fruit bats (Chiroptera: Pteropodidae: Cynopterinae)

The subfamily Cynopterinae comprises ca. 24 species of pteropodid bats (Family Pteropodidae) distributed exclusively in South and Southeast Asia. Although some studies have supported monophyly of the subfamily, molecular analyses have produced contradictory results and there has been little agreement on relationships of cynopterines to other megabat groups. However, no previous studies have included a complete sampling of cynopterine genera. Here we describe a phylogenetic analysis of Cynopterinae based on more than 6000 bp from six different genes sampled in representatives of all 14 recognized genera. Our results support the monophyly of Cynopterinae but refute a close relationship of cynopterines with Nyctimeninae. Within Cynopterinae, our analyses consistently recovered two monophyletic clades, which we recommend be recognized formally as tribes: Cynopterini and Balionycterini. Biogeographic analyses indicate a Sundaland origin of the Cynopterinae and divergence date estimates suggest different timing of diversification of the two major cynopterine clades.

Indirect flight of an African bat to Israel: an example of the potential for zoonotic pathogens to move between continents

The transmission of harmful pathogens during commercial air flights is an increasing health concern. A potential, yet relatively overlooked source of zoonotic infectious diseases involves collisions of birds and bats with aircraft and long distance transport of their carcasses. We report a case of aerial transportation of the remains of an African fruit bat over three continents, following a collision with an aircraft, and demonstrate the relative ease with which zoonotic pathogens, such as rabies virus or other viruses associated with bats, may cross national boundaries and continents even. Improper handling and disposal of animal remains by airport personnel, may lead to exposure of both humans and local fauna to exotic pathogens. This in turn may trigger an epidemic with potentially devastating results.

Phylogenetic systematics and tempo of evolution of the Viverrinae (Mammalia, Carnivora, Viverridae) within feliformians: Implications for faunal exchanges between Asia and Africa

We reconstructed the phylogeny of the subfamily Viverrinae (Mammalia, Carnivora, Viverridae) using a approximately 3kb data set in order to reassess timing and patterns of faunal exchanges between Asia and Africa. Maximum parsimony, maximum likelihood, and Bayesian analyses of separated and combined matrices (cytochrome b, transthyretin intron I and IRBP exon 1 [IRBP1]) recovered all the well-supported relationships within feliformian lineages. In addition, IRBP1 supported paraphyly of genus Herpestes and contributed to the resolution of equivocal hypotheses within Viverridae, including (1) the monophyly of Viverrinae, and (2) Viverricula sister-group of the other terrestrial civets (Civettictis and Viverra). The combined analysis yielded a robust phylogeny, recovering monophyly of Prionodontidae and yielding high posterior probabilities for nodes (1) (Prionodontidae, Felidae) and (2) ((Felidae, Prionodontidae), ((Hyaenidae, (Herpestidae, Eupleridae)), Viverridae)). Using a fossil cross-validation method, we estimated the emergence of Viverridae at 34.29Myr, with a separation between the three traditional subfamilies Hemigalinae, Paradoxurinae, and Viverrinae during the Late Oligocene-Early Miocene. The terrestrial civets and the splits between (1) Civettictis and Viverra and (2) Poiana and Genetta were estimated to appear during the Middle Miocene. Parsimony- and maximum likelihood-based methods yielded unambiguous ancestral area reconstructions, including the Asian origin of the family Viverridae, the subfamily Viverrinae, the terrestrial civets and the clade (Civettictis, Viverra). On the grounds of genetic distances, morphological divergence, and divergence time estimates, we propose the erection of the subfamily Genettinae (including Genetta and Poiana). Our analyses suggested two independent migration events from Asia to Africa, during the Middle Miocene (Civettictis) and between the Late Oligocene and Middle Miocene (Genettinae). These results are in agreement with the hypothesis of Miocene routes from Asia to Africa-via the Arabian microplate-that would have involved several independent events of migrations. Couched in the context of the viverrid fossil record, our study calls for a revision of the paleontological data in order to fully appreciate the complexity of Afro-Asian faunal exchanges.

History, ocean channels, and distance determine phylogeographic patterns in three widespread Philippine fruit bats (Pteropodidae)

The comparative phylogeography of widespread, codistributed species provides unique insights into regional biodiversity and diversification patterns. I used partial DNA sequences of the mitochondrial genes ND2 and cyt b to investigate phylogeographic structure in three widespread Philippine fruit bats. Ptenochirus jagori is endemic to the oceanic region of the Philippines and is most abundant in lowland primary forest. Macroglossus minimus and Cynopterus brachyotis are most common in disturbed and open habitats and are not endemic. In all three, genetic differentiation is present at multiple spatial scales and is associated to some degree with Pleistocene landbridge island groups. In P. jagori and C. brachyotis, genetic distance is correlated with geographic distance; in C. brachyotis and M. minimus, it is correlated with the sea-crossing distance between islands. P. jagori has the least overall genetic structure of these three species, whereas C. brachyotis and M. minimus have more geographic association among haplotypes, suggesting that phylogeographic patterns are linked to ecology and habitat preference. However, contrary to expectation, the two widespread, disturbed habitat species have more structure than the endemic species. Mismatch distributions suggest rapid changes in effective population size in C. brachyotis and P. jagori, whereas M. minimus appears to be demographically more stable. Geologic and geographic history are important in structuring variation, and phylogeographic patterns are the result of dynamic long-term processes rather than simply reflecting current conditions.

A phylogenetic supertree of the bats (Mammalia: Chiroptera)

We present the first estimate of the phylogenetic relationships among all 916 extant and nine recently extinct species of bats Mammalia: Chiroptera), a group that accounts for almost one-quarter of extant mammalian diversity. This phylogeny was derived by combining 105 estimates of bat phylogenetic relationships published since 1970 using the supertree construction technique of Matrix Representation with Parsimony (MRP). Despite the explosive growth in the number of phylogenetic studies of bats since 1990, phylogenetic relationships in the order have been studied non-randomly. For example, over one-third of all bat systematic studies to date have locused on relationships within Phyllostomidae, whereas relationships within clades such as Kerivoulinae and Murinae have never been studied using cladistic methods. Resolution in the supertree similarly differs among clades: overall resolution is poor (46.4%, of a fully bifurcating solution) but reaches 100% in some groups (e.g. relationships within Mormoopidae). The supertree analysis does not support a recent proposal that Microchiroptera is paraphyletic with respect to Megachiroptera, as the majority of source topologies support microbat monophyly. Although it is not a substitute for comprehensive phylogenetic analyses of primary molecular and morphological data, the bat supertree provides a useful tool for future phylogenetic comparative and macroevolutionary studies. Additionally, it identifies clades that have been little studied, highlights groups within which relationships are controversial, and like all phylogenetic studies, provides preliminary hypotheses that can form starting points for future phylogenetic studies of bats.

Phylogeny and evolution of African shrews (Mammalia: Soricidae) inferred from 16s rRNA sequences

Current phylogenetic hypotheses on the African Crocidurinae (Soricidae) are based upon morpho-anatomical, karyological, and allozyme studies. The present study attempts to resolve the interrelationships among African Crocidurinae and their relationships to Eurasian Crocidurinae and to the subfamily Soricinae, on the basis of partial mitochondrial 16s rRNA sequences (549 bp). This is the first molecular study to include all but one of the nine currently recognized African shrew genera. In agreement with current views, two major lineages emerge. The first lineage includes Myosorex and Congosorex and supports the existence of a myosoricine taxon. The second lineage includes the six remaining genera. The genus Sylvisorex appears to be polyphyletic, whereas species of the controversial genus Crocidura are monophyletic. The genus Suncus presumably originated in Africa. The monospecific genera Ruwenzorisorex and Scutisorex and the two representatives of Paracrocidura cluster with species of other genera. Grouping patterns of species from different continents suggest that there have been multiple exchanges between Africa and Eurasia. The time estimates of these exchanges, inferred from two independent fossil-based calibrations of a molecular clock, coincide with the time estimates for migration events in other mammalian taxa.