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1.
The recent discovery of hantaviruses in shrews and bats in West Africa suggests that other genetically distinct hantaviruses exist in East Africa. Genetic and phylogenetic analyses of newfound hantaviruses, detected in archival tissues from the Geata mouse shrew (Myosorex geata) and Kilimanjaro mouse shrew ( Myosorex zinki) captured in Tanzania, expands the host diversity and geographic distribution of hantaviruses and suggests that ancestral shrews and/or bats may have served as the original mammalian hosts of primordial hantaviruses.  相似文献   

2.
Forest or mouse shrews (Myosorex) represent a small but important radiation of African shrews generally adapted to montane and/or temperate conditions. The status of populations from Zimbabwe, Mozambique, and the north of South Africa has long been unclear because of the variability of traits that have traditionally been ‘diagnostic’ for the currently recognized South African taxa. We report molecular (mitochondrial DNA and nuclear DNA), craniometric, and morphological data from newly collected series of Myosorex from Zimbabwe (East Highlands), Mozambique (Mount Gorogonsa, Gorongosa National Park), and the Limpopo Province of South Africa (Soutpansberg Range) in the context of the available museum collections from southern and eastern Africa and published DNA sequences. Molecular data demonstrate close genetic similarity between populations from Mozambique and Zimbabwe, and this well‐supported clade (herein described as a new species, M yosorex meesteri sp. nov. ) is the sister group of all South African taxa, except for Myosorex longicaudatus Meester & Dippenaar, 1978. Populations of Myosorex in Limpopo Province (herein tentatively assigned to Myosorex cf. tenuis) are cladistically distinct from both Myosorex varius (Smuts, 1832) and Myosorex cafer (Sundevall, 1846), and diverged from M. varius at approximately the same time (2.7 Mya) as M. cafer and Myosorex sclateri Thomas & Schwann, 1905 diverged (2.4 Mya). Morphometric data are mostly discordant with the molecular data. For example, clearly distinct molecular clades overlap considerably in craniometric variables. On the other hand, extreme size differentiation occurs between genetically closely related populations in the Soutpansberg Range, which coincides with the bissection of the mountain range by the dry Sand River Valley, indicating the potential for strong intraspecific phenotypic divergence in these shrews. © 2013 The Linnean Society of London  相似文献   

3.
Five species of mouse or forest shrews (Myosorex) are endemic to South Africa, Lesotho and Swaziland, four of which (Myosorex varius, Myosorex cafer, Myosorex longicaudatus and Myosorex cf. tenuis) are associated with montane or temperate grassland, fynbos and/or forest habitats while a fifth (Myosorex sclateri) is associated with lowland subtropical forests. Due to their small size, specialised habitat, low dispersal capacity, high metabolism and sensitivity to temperature extremes, we predicted that, particularly for montane species, future climate change should have a negative impact on area of occupancy (AOO) and ultimately extinction risks. Species distribution models (SDMs) indicated general declines in AOO of three species by 2050 under the A1b and A2 climate change scenarios (M. cafer, M. varius, M. longicaudatus) while two species (M. sclateri and M. cf. tenuis) remained unchanged (assuming no dispersal) or increased their AOO (assuming dispersal). While temperate species such as M. varius appear to be limited by temperature maxima (preferring cooler temperatures), the subtropical species M. sclateri appears to be limited by temperature minima (preferring warmer temperatures). Evidence for declines in AOO informed the uplisting (to a higher category of threat) of the Red List status of four Myosorex species to either vulnerable or endangered as part of a separate regional International Union for Conservation of Nature (IUCN) Red List assessment.  相似文献   

4.
Seventeen extant populations of Microtus (Terricola) savii have been investigated for correlations of first lower molar shape to climatic variables by means of geometric morphometrics, and controlling for phylogenetic inheritance. Comparative methods revealed that climatic variables and phylogeography provide a very similar contribution to variation in first lower molars morphology, whereas tooth size does not appear to be affected by climatic conditions. Climate‐related changes have been recognized in the anteroconid portion of the tooth. This indicates that molar tooth variation is strongly influenced by climatic conditions, although in a complex way. Calabrian populations, often ascribed to Microtus (Terricola) brachycercus, form a distinct cluster, in agreement with the most recent genetic analyses. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 632–647.  相似文献   

5.
This represents the first study of the soricid community from the Early Pliocene site of Langebaanweg (LBW) which is represented by four species, two of which belong to the soricid genus Myosorex (Forest shrew). Using geometric morphometrics the two Myosorex fossil species are compared with each other, and the extant western and eastern Cape species: Myosorex varius, M. cafer and M. longicaudatus. In addition, the results from an analysis of a number of non-metric characters and linear measurements on the fossil species are presented. The mandibles of the fossil species are characterized by extremely broad teeth, ascending rami which are relatively gracile and differ in shape and size from modern species, and the existence of a number of primitive features of the mandibles and teeth. This evidence is interpreted as indicating that the two LBW Myosorex species represent an archaic lineage now extinct in southern Africa.  相似文献   

6.
Parnassius apollo (Linnaeus, 1758) is probably the most renowned Eurasian montane butterfly. Its specialized ecology makes it very sensitive to habitat and climate changes, so that it is now experiencing range contraction and local extinction across most of its range. We sequenced 869 bp of the mitochondrial DNA (mtDNA) cytochrome oxidase I gene in 78 P. apollo populations (201 individuals) in order to: (1) assess the phylogeographic pattern of the species; (2) shed light on the historical biogeographic processes that shaped the distribution of the species; and (3) identify geographic population units of special value for the conservation of the species' genetic diversity. Our analyses revealed a very strong phylogeographic structure in P. apollo, which displays a number of distinctive mtDNA lineages populating geographically distinct areas. Overall sequence divergence is relatively shallow, and is consistent with a recent (late Pleistocene) colonization of most of the range. We propose that P. apollo is best viewed as an atypical glacial invader in southern and western Europe, the isolated, montane populations of which, threatened by climate warming, retain a large fraction of the species evolutionary heritage. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 169–183.  相似文献   

7.
Lake Biwa is an ancient freshwater lake that was formed approximately 4 Mya and harbours many coastal plants that commonly inhabit the seashore. We used chloroplast DNA haplotype analysis using two spacer sequences and simple sequence repeat (SSR) analysis using eight nuclear microsatellite markers to detect genomic signatures indicating long‐term isolation of inland populations of Calystegia soldanella in Lake Biwa from coastal populations. We used 348 samples from 63 populations for haplotype analysis and 478 samples from 27 populations for SSR analysis covering the inland and coastal distribution of the species. We detected seven haplotypes, and the distribution pattern of these haplotypes was geographically highly structured between Lake Biwa and the coast. Nuclear SSR analysis also supported genetic differentiation between Lake Biwa and coastal populations (analyses of molecular variance, 43%), and the grouping of Lake Biwa and coastal populations by a Neighbour‐joining tree. In addition, genetic diversity of the inland populations (mean HE = 0.153) was significantly lower than that of coastal populations (mean HE = 0.328). These results suggested that inland populations at Lake Biwa have been isolated from coastal populations for a very long time. The inland populations most likely experienced a bottleneck effect, resulting in sufficient in situ genetic divergence to clearly distinguish them from coastal populations. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 51–66.  相似文献   

8.
The Caribbean archipelago offers one of the best natural arenas for testing biogeographic hypotheses. The intermediate dispersal model of biogeography (IDM) predicts variation in species richness among lineages on islands to relate to their dispersal potential. To test this model, one would need background knowledge of dispersal potential of lineages and their biogeographic patterns, which has been problematic as evidenced by our prior work on the Caribbean tetragnathid spiders. In order to investigate the biogeographic imprint of an excellent disperser, we study Trichonephila in the Americas. Trichonephila is a nephilid genus that contains globally distributed species known to overcome long, overwater distances. The results of our phylogenetic and population genetic analyses on T. clavipes suggest that populations over the Caribbean and North America maintain a lively gene flow. However, the single species status of T. clavipes over the entire New World is challenged by our species delimitation analyses. Combined with prior evidence from spider genera of different dispersal ability, these patterns coming from an excellent disperser (Trichonephila) that is species-poor and of a relatively homogenous genetic structure, support the IDM predictions.  相似文献   

9.
Subterranean rodents of the genus Ctenomys are an interesting system to assess the effects of habitat instability on the genetic structure of populations. The perrensi group is a complex of three species (C. roigi, C. perrensi and C. dorbignyi) and several forms of uncertain taxonomic status, distributed in the vicinity of the Iberá wetland in Argentina. Because of limited availability of suitable dry habitat, Ctenomys populations are distributed patchily around a vast mosaic of marshes, swamps and lagoons and become connected or isolated over time, depending particularly on the precipitation regime. Genetic variation at 16 microsatellite loci in 169 individuals collected in the area revealed eight clusters of populations which are thought to be evolutionary units, but which do not fit previous species limits. We interpret this lack of congruence between taxonomy and genetic structure as the result of a dynamic population structure. Where populations become connected, hybridization is possible. Where populations become isolated, rapid genetic divergence may occur. In the perrensi group, it appears that both of these factors disrupt the association between different genetic and morphological characters. The study of multiple characters is crucial to the understanding of the recent evolutionary history for dynamic systems such as this. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 368–383.  相似文献   

10.
Geographically structured variation in morphology is a common phenomenon in animals with environmental factors covarying with both latitude and biogeographic barriers having profound impacts on body size and shape. The Pacific blue-eye (Pseudomugil signifer) is a freshwater fish that lives along Australia’s east coast and occurs on either side of a terrestrial barrier, the Burdekin Gap. By quantifying the size and shape of males and females from 10 populations we found that Pacific blue-eyes are not sexually size dimorphism north of the Burdekin Gap whereas the degree of dimorphism was dependent upon latitude south of the barrier. Rensch’s rule was not supported as the degree of male-biased size dimorphism did not increase with increasing population mean body size. Body shape was related to body size and was sexually dimorphic south of the Burdekin Gap but not north of it. Our study represents a rare case of identifying how both body size and shape differ with respect to latitude and a major terrestrial biogeographic barrier and lends further support to the notion that P. signifer may comprise two species, or incipient species, that are separated by the Burdekin Gap.  相似文献   

11.
We examined approximately 600 specimens that represent the Praomys delectorum species group (Muridae: Murinae: Praomyini), a rodent complex restricted to Afromontane landscapes in East Africa and currently viewed as a single species. Morphometric analyses of 21 population samples consistently disclosed cohesive patterns of craniodental differentiation that support the recognition of three species: Praomys delectorum Thomas, confined to extreme southern Malawi; P. melanotus Allen & Loveridge, found in highlands of south‐western Tanzania and contiguous northern Malawi; and P. taitae Heller (including octomastis Hatt), distributed in mountains and foothills of southern Kenya and northern and central Tanzania. Populations of the P. delectorum group are patchily distributed in moist montane forest, most collecting localities falling within 1000–2400 m, and their range collectively coincides with the Tanganyika–Nyasa Montane Forest Group sensu Moreau. Patterns of faunal similarity derived from distributions of 65 species of terrestrial small mammals recorded from Tanzania's highlands, including the Eastern Arc Mountains, demonstrated pronounced geographical discontinuities in montane associations but failed to uncover a prominent vicariant role for the Makambako Gap. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165 , 420–469.  相似文献   

12.
The flyingfish family Exocoetidae is a diverse group of marine fishes that are widespread and abundant in tropical and subtropical seas. Flyingfishes are epipelagic specialists that are easily distinguished by their enlarged fins, which are used for gliding leaps over the surface of the water. Although phylogenetic hypotheses have been proposed for flyingfish genera based on morphology, no comprehensive molecular studies have been performed. In the present study, we describe a species‐level molecular phylogeny for the family Exocoetidae, based on data from the mitochondrial cytochrome b gene (1137 bp) and the nuclear RAG2 gene (882 bp). We find strong support for previous morphology‐based phylogenetic hypotheses, as well as the monophyly of most currently accepted flyingfish genera. However, the most diverse genus Cheilopogon is not monophyletic. Using our novel flyingfish topology, we examine previously proposed hypotheses for the origin and evolution of gliding. The results support the progressive transition from two‐wing to four‐wing gliding. We also use phylogenetic approaches to test the macroecological effects of two life history characters (e.g. egg buoyancy and habitat) on species range size in flyingfishes. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102, 161–174.  相似文献   

13.
The parietal, or third, eye is a photosensory organ situated in the middle of the skull of many lizards. Despite many hypotheses, its exact ecological functions are still unclear. Studies have compared the presence and absence of a functioning parietal eye, although there are no quantitative studies of parietal‐eye traits in relation to ecology, physiology or behaviour. In the present study, we report the first comparative study of relative parietal‐eye size in relation to climatic and thermophysiological variables. We studied thirty species of Liolaemus, a genus of South‐American lizards inhabiting a range of climatic conditions, but found little evidence for adaptation to thermal environment, in that parietal‐eye size did not vary meaningfully with latitude, altitude or any measures of environmental temperature. Neither did it relate to thermophysiology; there was a weak relation to thermal tolerance, although this was partially confounded with body size, which explained 23% of the among‐species variance after controlling for within‐species variation. The negative results obtained could not be explained by phylogenetic constraints because we found no evidence of phylogenetic inertia. We also observed high intraspecific variation indicating that parietal‐eye size may not be under strong selection for accuracy. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 870–883.  相似文献   

14.
The study of intraspecific variation of acoustic signals and its relationship with genetic divergence is important for understanding the origin of divergence in communication systems. We studied geographical variation in the acoustic structure of advertisement calls from five populations of the four‐eyed frog, Pleurodema thaul, and its relationship with the genetic divergence among these populations. By analyzing temporal and spectral parameters of the advertisement calls, we report that the signals of northern, central, and southern populations have remarkable differences between them. A phylogeographical analysis from a mitochondrial DNA fragment demonstrated three phylogenetic groups coincident with those found with the bioacoustics analysis. Furthermore, bioacoustic and genetic distances show significant correlations after controlling for geographical distance. These results suggest that behavioural divergence among populations of P. thaul has a phylogenetic basis, supporting three evolutionary units within this species, as well as prompting the exploration of divergence processes in the sound communication system of this species. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110 , 142–155.  相似文献   

15.
Material ascribed to the genus Callulina from north‐east Tanzania and south‐east Kenya is assessed. Three new species of Callulina are described from the North ( Callulina laphami sp. nov. ) and South ( Callulina shengena sp. nov. and Callulina stanleyi sp. nov. ) Pare Mountains in Tanzania. The species are diagnosed based on morphological, acoustic, and molecular data. A new key to the species of Callulina is provided. Based on an interpretation of the International Union for Conservation of Nature (IUCN) red list, we suggest that the three species will qualify as critically endangered, because of their small distributions and the ongoing threat to their habitat. We reveal the high local endemism of Callulina in the northern part of the Eastern Arc Mountains, with each species restricted to no more than one mountain (fragment) block. This high local endemism in Callulina is probably widespread across the Eastern Arc, raising further conservation concern for this group of amphibians. Based on new molecular phylogenetic data for Callulina, we discuss biogeographical relationships among north‐east Tanzanian mountains, and evolutionary patterns in Eastern Arc breviciptids. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 496–514.  相似文献   

16.
Extreme variation in early life‐history strategies is considered a moderately good predictor of genetic subdivision and hence dispersal for a range of marine species. In reality, however, a good deal of population differentiation must reflect historical effects, more subtle variation in life histories, and, particularly, the interaction of larvae with oceanographic processes. Using a combination of allozyme and microsatellite markers, we show that the large‐scale genetic structure of populations of three species (direct and planktonically developing cushion stars and a planktonic developing sea anemone that is also asexually viviparous) varies consistently, in line with the predicted capacity for dispersal within three geographic regions. We detected high levels of genetic subdivision for the direct developing cushion star (FST = 0.6), low levels for the planktonically developing cushion star (FST = 0.009), and intermediate levels for the sexual/asexual sea anmone (FST = 0.19). These patterns are exhibited despite the highly variable patterns of current movement and the presence of biogeographic barriers. Our results suggest that, although there is large scale genetic differentiation for two species, patterns of population connectivity are remarkably consistent within major regions and do not reflect variation in major oceanographic processes or genetic discontinuity coincident with biogeographic boundaries. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 106–116.  相似文献   

17.
The present study employed basic and molecular cytogenetic methods to characterize three populations of Parauchenipterus galeatus from the basins of the Paraná and São Francisco Rivers, and a region of connection between the two basins. Although the diploid number was equal to 58 chromosomes, variations in karyotype formula were detected among the populations. B chromosomes were detected only in the population from the São Francisco River. Heterochromatin was located in the terminal position in almost all the chromosomes and in the pericentromeric position in some acrocentric chromosomes in the three populations. A single nucleolus organizer region was detected by silver nitrate and 18S rDNA‐fluorescent in situ hybridization in the short arm of one subtelocentric pair in the three populations, varying only in the chromosome pair bearing this site. The 5S rDNA sites were located in two submetacentric chromosome pairs in the three populations, varying only in the chromosome pairs bearing these sequences. Classic and molecular chromosome markers, along with the context of the natural history of the formation of hydrographic basins, ecological aspects, and the geographic isolation of populations between hydrographic basins and within the same basin, were important contributions to the discussion on possible biogeographic relations among the populations of Parauchenipterus galeatus. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 648–656.  相似文献   

18.
African mole‐rats of the family Bathyergidae are subterranean hystricomorph rodents found throughout sub‐Saharan Africa, where the distributional ranges of the most speciose taxa are divided by the African Rift Valley. In particular, mole‐rats of the genera Heliophobius and Fukomys are distributed widely, and their adaptive radiation appears to have been strongly influenced by the geological process of rifting. As a result, virtually all members of the genus Fukomys occur in locations west of the Rift Valley. However, a small number of isolated populations occur east of the Rift Valley in Tanzania, where Heliophobius is widespread and is the predominant bathyergid rodent. Phylogenetic analysis of mitochondrial cytochrome b sequences of previously unstudied Tanzanian mole‐rats (genus Fukomys) and geographically adjacent populations strongly suggests that vicariance in the Western Rift Valley has subdivided populations of mole‐rats and, together with climatic changes, played a role in the isolation of extralimital populations of Fukomys in Tanzania. Together with molecular clock‐based estimates of divergence times, these results offer strong support for the hypothesis that the observed patterns of cladogenesis are consistent with tectonic activity in the ‘Mbeya triple junction’ and Rungwe volcanic province between Lakes Rukwa and Nyasa. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 337–352.  相似文献   

19.
The world's richest mangrove‐restricted avifauna is in Australia and New Guinea. The history of differentiation of the species involved and their patterns of intraspecific genetic variation remain poorly known. Here, we use sequence data derived from two mitochondrial protein‐coding genes to study the evolutionary history of eight co‐distributed mangrove‐restricted and mangrove‐associated birds from the Australian part of this region. Utilizing a comparative phylogeographical framework, we observed that the study species present concordantly located phylogeographical breaks across their shared geographical distribution, a plausible signature of common mechanisms of vicariance underlying this pattern. Barriers such as the Canning Gap, Bonaparte Gap, and the Carpentarian Gaps all had important but varying degrees of impact on the studied species. The Burdekin Gap along Australia's eastern seaboard probably had only a minor influence as a barrier to gene flow in mangrove birds. Statistical phylogeographical simulations were able to discriminate among alternative scenarios involving six different geographical and temporal population separations. Species exhibiting recent colonizations into mangroves include Rhipidura phasiana, Myiagra ruficollis, and Myzomela erythrocephala. By contrast, Peneoenanthe pulverulenta, Pachycephala melanura, Pachycephala lanioides, Zosterops luteus, and Colluricincla megarhyncha all had deeper histories, reflected as more marked phylogeographical divisions separating populations on the eastern seaboard/Cape York Peninsula from more western regions such as the Arnhem Land, the Pilbara, and the Kimberley. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 574–598.  相似文献   

20.
We studied the phenotypic variation of the Atlantic Forest passerine Xiphorhynchus fuscus (Aves: Dendrocolaptidae) with the broad aim of addressing whether the history and type of forest affected the evolution of endemic taxa. We also tested whether the different subspecies and genetic lineages of X. fuscus could be considered full species. We collected plumage and body size measurements and, in combination with genetic data, used multivariate tests to evaluate the working hypotheses. Our results, combined with previous biogeographic analyses, indicate that vicariant events have been important determinants in the evolution of phenotypic characters of X. fuscus, once genetic isolation was complete. Our analysis also suggests that forest heterogeneity and ecotones are important factors in the early evolution of Atlantic Forest taxa, perhaps via divergent selection. Forest instability during the Pleistocene was critical in the evolution of phenotypic traits. We confirm that the subspecies atlanticus should be considered a full species. Other lineages or populations are also phenotypically differentiated but we do not suggest considering them as full species. They share high levels of gene flow and are part of a continuous latitudinal cline of phenotypic variation. Our study suggests that not all the historic events in the Atlantic Forest that affected the evolution of genetic lineages also influenced the evolution of phenotypic characters in the same direction and intensity. Undoubtedly, natural selection played a major role in the evolution of Atlantic Forest organisms. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 1047–1066.  相似文献   

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