Population genetic structure of Sorex unguiculatus and Sorex caecutiens (Soricidae, Mammalia) in Hokkaido, based on microsatellite DNA polymorphism

We investigated the genetic structure of Sorex unguiculatus and Sorex caecutiens populations in Hokkaido, Japan, using hypervariable microsatellite DNA markers. We used five microsatellite loci to type 475 S. unguiculatus individuals from 20 localities on the Hokkaido mainland and four localities from each of four offshore islands (and 11 shrews from one locality in southern Sakhalin for a particular analysis). We used six microsatellite loci to type 240 S. caecutiens individuals from 13 localities on the Hokkaido mainland. Genetic variation was high in mainland populations of both species and low in the island populations of S. unguiculatus. Allelic richness and island size were positively correlated for S. unguiculatus, suggesting that genetic drift occurred on those islands due to small population size. In addition, four insular populations of S. unguiculatus were genetically differentiated from the mainland populations, although clear phylogeographic clustering was not confirmed among populations on the Hokkaido mainland for either S. unguiculatus or S. caecutiens. Heterozygosity excess was observed in more than half of the populations including the mainland populations of the two species, suggesting recent bottleneck events in these populations. Population dynamics of the shrews might be explained by a metapopulation scheme. According to autocorrelation analysis, the extent of non-random spatial genetic structure was approximately 100 km. Isolation by distance was observed in S. unguiculatus, but not in S. caecutiens although there is a positive trend. The lack of correlation for S. caecutiens might have been due to small sample size. Thus, no obvious differences in population genetic structure were found between the two species on the Hokkaido mainland in the present study, while previous investigations using mitochondrial DNA sequences inferred that these two species might have rather different biogeographic histories.     

Isolation and characterization of polymorphic microsatellite DNA markers in two shrew species,Sorex unguiculatus and S. caecutiens

We isolated six microsatellite markers from the partial genomic libraries of two Sorex shrews, S. unguiculatus and S. caecutiens, and examined their allelic variation. All loci showed high allelic variation ranging from 15 to 19 alleles and all but one locus conformed to Hardy–Weinberg expectations in the species where the loci were isolated. Cross-species amplifications showed that all primers derived from S. unguiculatus were useful for S. caecutiens, while among primer sets derived from S. caecutiens only one was useful for S. unguiculatus. Accordingly, at least five microsatellite markers were useful in S. caecutiens and three in S. unguiculatus.     

Borrelia japonica in Nature: Genotypic Identification of Spirochetes Isolated from Japanese Small Mammals

Spirochetes were isolated from earlobe tissues of shrews (Sorex unguiculatus, Sorex caecutiens, and Crocidura dsinezumi), voles (Clethrionomys rufocanus), and mice (Apodemus argenteus and Apodemus speciosus) captured in various localities in Japan. The isolates were identified as Borrelia japonica by rRNA gene restriction fragment length polymorphism analysis. The data suggest that these small mammals are candidates of reservoir hosts for B. japonica.     

Analysis of biodiversity parameters of shrew communities of the Altai Mountains

The communities of insectivorous mammals of the Altai Mountains, each consisting of 4–9 species, are quite similar in species composition and principles of organization. The forest belt of mountains is dominated by the common shrew (Sorex araneus), with the Laxmann’s (Sorex caecutiens), lesser (Sorex minutus), and tundra (Sorex tundrensis) (rarely even-toothed (Sorex isodon)) shrews being codominants. With altitude, the dominants change and some species disappear but no significant changes in the dominance structure of the community occur. Positive correlations between abundance rates recorded in different years and on different plots indicate the stability of communities under study. Analysis of informational indices of diversity reveals four basic possible conditions of communities: a) relatively safe, b) slightly disturbed, c) disturbed, and d) high-altitude slightly evened.     

An analysis of interspecific relationships ofSaguinus based on cranial measurements

The interspecific relationships of the following nine forms ofSaguinus were analyzed applying the multivariate analysis to the cranial measurements;S. oedipus, S. geoffroyi, S. leucopus, S. nigricollis, S. fuscicollis, S. labiatus, S. mystax, S. midas midas, andS. midas niger. Penrose's size distance was used to express the size factor among the nine forms; and for the shape factor, Q-mode correlation coefficients were utilized. The shape distance betweenS. oedipus andS. geoffroyi was almost equal to that betweenS. nigricollis andS. fuscicollis which are recognized as different species based on biogeographical evidence. Furthermore, the Penrose's size distance betweenS. oedipus andS. geoffroyi was quite large. Therefore, the results of this study support the hypothesis thatS. oedipus andS. geoffroyi are valid species. The analysis of the phylogenetic relationships among the nine forms was based on the shape factor only. The forms were divided into two main clusters: (1)S. oedipus, S. geoffroyi, andS. leucopus; (2)S. nigricollis, S. fuscicollis, S. labiatus, S. mystax, S. midas midas, andS. midas niger. In the former cluster,S. oedipus was more closely related toS. geoffroyi than either was toS. leucopus. The latter cluster was subdivided in two subclusters based on the degree of their affinity: (2a)S. nigricollis, S. fuscicollis, S. labiatus, andS. mystax; and (2b)S. midas midas andS. midas niger. In the former subcluster, [S. nigricollis, S. fuscicollis] and [S. labiatus, S. mystax] were classified into clusters, respectively. The ancestor of theS. nigricollis group differentiated intoS. oedipus, S. geoffroyi, andS. leucopus with the narrowing of the maxilla in the facial region, andS. midas midas andS. midas niger with the downward movement of rhinion.     

Hyphomorpha als Phycobiont in Flechten

Hyphomorpha, a genus of theStigonematales, is confirmed to be a phycobiont in twoSpilonema species (Coccocarpiaceae). The morphology of the symbiotic algae inSpilonema dendroides andS. schmidtii is described. The phycobiont inS. dendroides is possiblyHyphomorpha antillarum, the alga inS. schmidtii might be a species related toH. perrieri. New localities for the rare lichens are reported: Alaska forS. dendroides and Ceylon forS. schmidtii.

     

Intraspecific invariability of the internal transcribed spacer region of rDNA of the truffleTerfezia terfezioides in Europe

ITS regions (internal transcribed spacers—ITS1 andITS2—with the 5.8S gene of the nuclear rDNA) of 25 fruit body samples ofTerfezia terfezioides, originating from Hungary and Italy, were compared. The amplification and sequencing of the ITS region was successful with both theITS1-ITS4 andITSIF-ITS4 primer pairs. No differences of the restriction fragment length polymorphism profiles were detected among 19 samples collected in one place at the same time. The sequences of the ITS region of 9 samples collected in different localities were highly invariable, differing in only two bases. Thus the intraspecific homogeneity of the ITS region seems to be an important species-specific characteristic ofT. terfezioides in contrast to otherTerfezia species. As the samples of the species were collected from different and distant localities of Europe, the ITS sequence ofT. terfezioides can be considered a very conservative, reliable molecular marker of the fungus. *** DIRECT SUPPORT *** A00EN076 00008     

Cranial adaptation to a high attrition diet in Japanese macaques

Primates with diets that require greater occlusal forces to process exhibit anteroposteriorly shorter, vertically deeper faces, more anteriorly placed masseter attachment areas, and broader, taller mandibular corpora compared to closely related species/populations. Japanese macaques (Macaca fuscata)eat different, perhaps mechanically tougher to process, foods than other macaques do. Accordingly, they should exhibit structural features of the skull related to dissipating great occlusal loads. To test this hypothesis I compared cranial variables amongst wild-caught, adult female skulls (n = 85) of M. fuscataand three other macaque species (M. mulatta, M. fascicularis,and M. nemestrina)and applied least-squares and reduced-major-axis regression analysis and principal components analysis (PCA) to 17 cranial variables reflecting facial, vault, and mandibular dimensions. When scaled for size, the Japanese macaque has a vertically deeper and anteroposteriorly shorter face,a broader but not taller mandibular corpus, and a more anteriorly placed masseter muscle than the other three macaques do. The first PCA axis isolates variation due to a suite of characters related to mechanical efficiency in dissipating occlusal loads (vertically deep face and broad corpus) and differentiates the Japanese macaques from the other species. This, coupled with reported dietary differences among species, suggests that Japanese macaques are selected for dissipating greater occlusal loads than other macaques are. The presence of a narrow mandible relative to cranial breadth and a hyperrobust mandibular corpus width suggests that axial torsion is a significant influence in the masticatory regime of M. fuscata.The lack of an increase in corpus height indicates that parasagittal bending is not as significant an influence. Geographic and climatic influences cannot account for the patterns of variation between M. fuscataand the other macaques.     

Evolution of the mandibular symphysis in Notharctinae (Adapidae,Primates)

The Eocene Notharctinae provide a record of increasing fusion of the mandibular symphysis. The two sympatric genera,Notharctus andSmilodectes, differed through time in two respects.Notharctus increased in body size and evolved a partially fused mandibular symphysis.Smilodectes changed little in body size and retained an unfused symphysis. Similarities in molar morphology between these two genera and extant leaf-eating mammals suggest thatNotharctus andSmilodectes were specialized for folivory, a dietary regime correlated with partial symphyseal fusion in many extant mammals. It is concluded that the presence and the extant of symphyseal fusion is a function of body size, diet, and jaw mechanics, complicated by lineagespecific factors that vary among higher mammalian taxa.     

Distribution patterns and microhabitat segregation in gastrointestinal helminths of Sorex shrews

We studied the distribution patterns and microhabitat use in gastrointestinal helminths of the shrews Sorex araneus and S. caecutiens in Finland. The distribution of species prevalences was bimodal, and in S. araneus the abundance (mean intensity) was positively associated with commonness (prevalence), as assumed by the core-satellite species hypothesis (Hanski 1982). However, the positive correlation between prevalence and intensity was observed only when the effects of helminth body size and taxonomic group (cestodes vs nematodes) on intensity were controlled for. The nematodes of the genus Longistriata occurred predictably as core species, whereas the identity of the core cestodes was more variable between host species and regions. Helminth body size and taxonomic group were not related to the degree of aggregation in shrew populations, but helminth body size seemed to explain the differences in the distribution patterns of helminths between shrews and voles. The core species did not show more segregation in microhabitat use than randomly selected species. In fact, the two core nematodes showed largely overlapping intestinal distributions. We conclude that linear intestinal space is not a key resource for shrew nematodes, but it may be for shrew cestodes.     

Differences in morphology and reproductive traits of Galerucella nymphaeae from four host plant species

The water lily beetle Galerucella nymphaeae L. (Coleoptera: Chrysomelidae) exploits different hosts, including Nuphar lutea Sm. and Nymphaea alba L. (both Nymphaeaceae), as well as Polygonum amphibium L. and Rumex hydrolapathum Hudson (both Polygonaceae). The present study investigates whether within-species differences in morphological and reproductive traits are associated with differences in host species exploitation. A total of 1103 adult beetles were collected from 11 localities in The Netherlands, one of which contained all four hosts and three other localities contained hosts from both families (sympatric localities). Adults originating from Nuphar and Nymphaea were on average darker in colour and larger in size and had disproportionally bigger mandibles than beetles originating from Polygonum and Rumex across the 11 localities. Head capsules of first instar larvae from Nymphaeaceae hosts were between 17% and 28% larger than those of larvae from Polygonaceae hosts. Furthermore, beetles from Nuphar and Nymphaea laid larger sized eggs, but fewer eggs per clutch than beetles originating from Polygonum and Rumex. Although host related variation was less pronounced at the sympatric localities than in the allopatric localities, differences in larval and adult size were still highly significant at the sympatric localities. It is not clear whether the observed differences are genetically based, as opposed to host induced. However, leaf toughness varied among species in a way suggesting that leaf toughness may be partly responsible for host related differences in G. nymphaeae.     

Tamarin polyspecific associations: Forest utilization and stability of mixed-species groups

Niche separation is likely to play a key role in the formation of mixed-species groups. Saddle-backed tamarins (Saguinus fuscicollis) were studied at three sites with different primate communities in northern Bolivia: (1) with red-bellied tamarins,S. labiatus; (2) with emperor tamarins,S. imperator; and (3) without a congeneric species. The degree of association is higher betweenS. labiatus andS. fuscicollis than betweenS. imperator andS. fuscicollis and is related to differences in forest utilization between associating pairs. Niche separation is found to be greater betweenS. labiatus andS. fuscicollis than betweenS. fuscicollis andS. imperator. The mean height and habitat utilization ofS. fuscicollis does not differ greatly across the three sites, nor does the height of tamarins in and out of association. It is concluded that combined with differences in body size and dietary overlap, vertical segregation plays an important role in tamarin polyspecific associations (increasing the potential of both foraging and anti-predatory benefits) and that this is not a consequence of vertical displacement ofS. fuscicollis by its dominant congeners.     

A phylogenetic analysis ofAcetobacterium woodii,Clostridium barkeri,Clostridium butyricum,Clostridium lituseburense,Uubacterium limosum,andEubacterium tenue

Acetobacterium woodii, Butyribacterium rettgeri, Clostridium barkeri, Clostridium butyricum, Clostridium lituseburense, Eubacterium limosum, andEubacterium tenue have been characterized by oligonucleotide cataloging of their 16S ribosomal RNAs.A. woodii, C. barkeri, andE. limosum form a related group.C. lituseburense andE. tenue are highly related. As previously reported,E. limosum andB. rettgeri are synonymous. TheEubacterium species examined here are less related to each other than they are to different species ofClostridium. Mol% G+C of DNA and murein composition support the 16S ribisomal RNA data. These findings question the validity of current taxonomic distinctions for these Gram-positive anaerobes.     

Phylogenetic evaluation of 5S ribosomal RNA gene and spacer in theCallistachys group (Fabaceae:Mirbelieae)

Sequences of 5S rDNA from an Australian group of papilionoid legumes were evaluated for phylogenetic informativeness. Twenty four sequences were sampled from ten species in five closely related genera:Brachysema, Callistachys, Jansonia, Nemcia andPodolobium. These sequences fell into two size classes, 200bp and 600bp, which appear to represent paralogous copies of the 5S unit at different loci. As in previous studies, the 5S rRNA gene and both ends of the inter-gene spacer are found to be conserved and almost uninformative about phylogeny at this taxonomic level. By contrast, the middle part of the spacer is highly variable, both in substitutions at individual sites and in length. The short sequences contain virtually no duplications. The long sequences contain numerous short repeats (c.20 bp) which form a regular pattern in the middle section. Phylogenies estimated from these data support monophyly of the study group, and of species. Relationships among species and genera are less clear, perhaps because divergence of the 5S spacer between species is too great. However, non-monophyly ofNemcia andBrachysema, indicated by other data, is corroborated.     

Preliminary analysis of numerical taxonomy of the genusSaguinus based on dental measurements

Although several investigations have been made from different viewpoints, the classification or interspecific relationships ofSaguinus still remain uncertain. In the present study, we applied multivariate analysis methods to dental measurements of part ofSaguinus populations of sufficient sample size and obtained the following conclusions.Saguinus can be classified into two main groups: one consists ofS. oedipus andS. leucopus, and the other ofS. fuscicollis, S. nigricollis, S. labiatus, andS. mystax. Concerning the former group, the two subspecies ofS. oedipus, S. o. oedipus, andS. o. geoffroyi, show a close affinity with each other and also a close relationship toS. leucopus, while the latter group consists of two subgroups of species, one includingS. fuscicollis andS. nigricollis, and the other includingS. labiatus andS. mystax. The biological distance betweenS. oedipus oedipus andS. o. geoffroyi is slightly larger than that between the pairs ofS. fuscicollis andS. nigricollis and ofS. labiatus andS. mystax. Factor analysis revealed significant factors which could explain the differences among the seven maleSaguinus populations. Taking all the results into account, it seems necessary to reconsider the phylogenetic relationships within the genusSaguinus.     

Phylogenetic relationships in theSideritis leucantha group (Lamiaceae)

Six closely related taxa of the sect.Eusideritis of the genusSideritis (S. leucantha, S. pusilla, S. flavovirens, S. granatensis, S. biflora andS. osteoxylla) are analysed to elucidate their phylogenetic relationships and position within the sect.Eusideritis. Meiotic behaviour, karyotype features, size and fertility of pollen grains, DNA amounts and seed protein profiles are reviewed. A polyploid origin of the group (from x = 7) and the further diversification through dysploidy and chromosome repatterning is postulated.S. osteoxylla is apparently of hybrid origin.     

Genetic variation in the mitochondrial 16S rRNA gene of the American dog tick,Dermacentor variabilis (Acari: Ixodidae)

Genetic variation in the mitochondrial (mt) 16S ribosomal RNA (rRNA) gene was examined for the American dog tick, Dermacentor variabilis (Say, 1821). Nine different haplotypes were detected among 369 adult D. variabilis collected from four localities in Canada. There were eight variable nucleotide positions in the 404 bp sequence alignment. Individuals of haplotype 1 occurred at frequency of >75% at all localities. Five haplotypes were detected at only one of the four localities. High haplotype diversity and low nucleotide diversity, combined with significantly negative F_s values for ticks at three localities, suggest a recent population expansion. Genetic differences were found between populations at different localities, but a Mantel regression analysis revealed no association between genetic differences and geographical distances. There was also no association between tick haplotype and the prevalence of the bacterium, Rickettsia montanensis Weiss and Moulder, 1984, in D. variabilis among localities or on opposite sides of Blackstrap Lake (Saskatchewan). The 16S rDNA haplotypes from Canadian populations of D. variabilis formed a clade with those from the eastern and central U.S.A., to the exclusion of D. variabilis from geographically isolated populations in the western U.S.A. Although sample sizes for D. variabilis in the eastern U.S.A. are small, there may be genetic divergence between populations in Canada and those in the eastern U.S.A., which may have implications for studies on the pathogenic agents transmitted by D. variabilis to its hosts.     

A revision of Sullivantia (Saxifragaceae)

Sullivantia (Saxifragaceae) is restricted to the United States; its species occur in very specialized habitats such as wet cliffs and moist canyon walls in scattered localities from Washington and Oregon, eastward to Wyoming, Montana, Colorado, Missouri, Iowa, Illinois, Minnesota, Wisconsin, Indiana, Ohio, and Virginia. Relationships in the genus were reevaluated using data from morphology (including the use of greenhouse-grown plants), crossability, and flavonoid chemistry. The conclusion of this study is thatSullivantia comprises four morphologically similar allopatric taxa:S. oregana, S. hapemanii var.hapemanii, S. hapemannii var.purpusii, andS. sullivantii.     

Ecology of epiphyllous liverworts: growth in three natural habitats in Western Nigeria

Abstract

The growth of four epiphyllous liverworts, Radula jiaccida, Caudalejeunea hanningtonii, Leptolejeunea astroidea, and Cololejeunea pusilla var. obtusifolia, has been followed for a period of about 18 months at three different localities in Western Nigeria over three height-ranges above the ground. The three localities experience different climatic conditions and possess different vegetation. Growth was found to be related to the size of the species, the larger ones always exhibiting faster growth. The liverworts also showed periodicity in growth, related to the wet and dry seasons. There was no period of dormancy, though growth was drastically reduced during the dry season.     

Systematic and morphological diversity of endosymbiotic methanogens in anaerobic ciliates

The identities and taxonomic diversity of the endosymbiotic methanogens from the anaerobic protozoaMetopus contortus, Metopus striatus, Metopus palaeformis, Trimyema sp. andPelomyxa palustris were determined by comparative analysis of their 16S ribosomal RNA sequences. Fluorescent oligonucleotide probes were designed to bind to the symbiont rRNA sequences and to provide direct visual evidence of their origins from methanogenic archaea contained within the host cells. Confocal microscopy was used to analyze the morphology of the endosymbionts in whole cells ofMetopus palaeformis, Metopus contortus, Trimyema sp. andCyclidium porcatum. The endosymbionts are taxonomically diverse and are drawn from three different genera;Methanobacterium, Methanocorpusculum andMethanoplanus. In every case the symbionts are closely related to, but different from, free-living methanogens for which sequences are available. It is thus apparent that symbioses have been formed repeatedly and independently. Ciliates which are unrelated to each other (Trimyema sp. andMetopus contortus) may contain symbionts which are closely related, and congeneric ciliates (Metopus palaeformis andM. contortus) may contain symbionts which are distantly related to each other. This suggests that some of the symbiotic associations must be relatively recent. For example, at least one of the symbioses inMetopus must postdate the speciation ofM. palaeformis andM. contortus. Despite this,Metopus contortus, Trimyema sp., Cyclidium porcatum and their respective endosymbionts show sophisticated morphological interactions which probably facilitate the exchange of materials between the partners.