Conservation status of the two cryptic species of Hamatocaulis vernicosus (Bryophyta) in Sweden

Cryptic species are rarer than their combined, morphologically recognisable species. Each cryptic species may have its own habitat requirements and distribution, and each should be considered separately in biodiversity conservation. This investigation explores how well the two cryptic species of the wetland moss Hamatocaulis vernicosus (Mitt.) Hedenäs s.l., included in Annex II of the EU Habitat Directive, are safeguarded in existing protected sites in Sweden. Further, the northern distribution limit of the southern of the two cryptic species is explored. The distributions of the two cryptic species and their intraspecific variation are judged by the nuclear ITS1?+?2 and the two chloroplast markers rpl16 and trnL-trnF for a set of 89 specimens. The genetic differences between the two cryptic species are significant, but there are no differences between the protected and non-protected subsets within the respective species. The protected areas therefore represent these two species’ genetic variation well. The populations of both cryptic species appear stable, according to their genetic signals. One of the two cryptic species occurs almost throughout Sweden, whereas the other occurs only to the south of the southern limit of the southern boreal zone, except for two finds slightly further north in climatically mild areas.     

基于线粒体细胞色素b基因分析海南岛褐家鼠种群遗传多样性

褐家鼠(Rattus norvegicus)是海南岛的主要害鼠之一,海南岛是我国南方海上的重要交通口岸,但关于海南岛褐家鼠的种群遗传多样性以及和邻近地区褐家鼠种群间的基因交流情况还缺乏了解。本研究测序分析了来自海南岛、广东、越南等地91只褐家鼠的细胞色素b基因,分析了不同种群中的Cyt b单倍型,种群间的遗传分化程度(F_(st)),构建了全世界60个褐家鼠的Cyt b单倍型之间的系统进化关系。结果发现,海南岛琼中/澄迈和崖城的褐家鼠种群没有共享的Cyt b单倍型,种群间出现了明显的遗传分化(F_(st)=0.453),但这两个群体分别与广东和菲律宾/越南的褐家鼠分享共同的单倍型,表明海南岛褐家鼠与广东和菲律宾/越南褐家鼠近代存在着基因交流。系统进化分析结果表明,多数海南岛和广东褐家鼠的Cyt b单倍型来自共同的单倍型组CⅢ和CⅦ,说明海南岛和广东省的褐家鼠可能由一个或多个共同的祖先种群扩散而来。由于褐家鼠喜欢与人伴生,褐家鼠很可能随着黎族人在新石器时代中期(大约3 000年前)或更早以前,从广西、广东沿海地区迁移至海南。     

Molecular phylogeography of two sibling species of <Emphasis Type="Italic">Eurema</Emphasis> butterflies

The common yellow butterfly Eurema hecabe is widely distributed in East Asia, and is one of the most burdensome species for taxonomists due to the numerous geographic and seasonal wing colour patterns. Moreover, within this species, individuals with a yellow wing fringe that occur in temperate regions of Japan (Y type) proved to be biologically different from others that occur widely in subtropical regions of Japan and all over East Asia (B type). To unveil the genetic variation within and between the two types, a total of 50 butterflies collected at 18 geographic localities in East Asia were examined for nucleotide sequence variation of three mitochondrial regions: cytochrome c oxidase subunit I (COI), cytochrome c oxidase subunit III (COIII) and NADH dehydrogenase subunit 5 (ND5). In addition, they were also examined for infection status with the endosymbiotic bacteria Wolbachia. The three mitochondrial sequences consistently showed that (i) Y type and B type were highly divergent, (ii) nucleotide variation within B type was very small although sampled from a geographically wide range, and (iii) a weak association existed between mitochondrial DNA haplotypes and Wolbachia infection status.     

Phylogeography of <Emphasis Type="Italic">Ceriops tagal</Emphasis> (Rhizophoraceae) in Southeast Asia: the land barrier of the Malay Peninsula has caused population differentiation between the Indian Ocean and South China Sea

The genetic structure of mangrove species is greatly affected by their geographic history. Nine natural populations of Ceriops tagal were collected from Borneo, the Malay Peninsula, and India for this phylogeographic study. Completely different haplotype compositions on the east versus west coasts of the Malay Peninsula were revealed using the atpB-rbcL and trnL-trnF spacers of chloroplast DNA. The average haplotype diversity (Hd) of the total population was 0.549, nucleotide diversity (θ) was 0.030, and nucleotide difference (π) was 0.0074. The cladogram constructed by the index of population differentiation (G _ST) clearly separated the South China Sea populations from the Indian Ocean populations. In the analysis of the minimum spanning network, the Indian Ocean haplotypes were all derived from South China Sea haplotypes, suggesting a dispersal route of C. tagal from Southeast Asia to South Asia. The Sunda Land river system and surface currents might be accountable for the gene flow directions in the South China Sea and Bay of Bengal, respectively. The historical geography not only affected the present genotype distribution but also the evolution of C. tagal. These processes result in the genetic differentiation and the differentiated populations that should be considered as Management Units (MUs) for conservation measurements instead of random forestation, which might lead to gene mixing and reduction of genetic variability of mangrove species. According to this phylogeographic study, populations in Borneo, and east and west Malay Peninsula that have unique genotypes should be considered as distinct MUs, and any activities resulting in gene mixing with each other ought to be prevented.     

Out-of-Africa,human-mediated dispersal of the common cat flea,Ctenocephalides felis: The hitchhiker’s guide to world domination

The cat flea (Ctenocephalides felis) is the most common parasite of domestic cats and dogs worldwide. Due to the morphological ambiguity of C. felis and a lack of — particularly largescale — phylogenetic data, we do not know whether global C. felis populations are morphologically and genetically conserved, or whether human-mediated migration of domestic cats and dogs has resulted in homogenous global populations. To determine the ancestral origin of the species and to understand the level of global pervasion of the cat flea and related taxa, our study aimed to document the distribution and phylogenetic relationships of Ctenocephalides fleas found on cats and dogs worldwide. We investigated the potential drivers behind the establishment of regional cat flea populations using a global collection of fleas from cats and dogs across six continents. We morphologically and molecularly evaluated six out of the 14 known taxa comprising genus Ctenocephalides, including the four original C. felis subspecies (Ctenocephalides felis felis, Ctenocephalides felis strongylus, Ctenocephalides felis orientis and Ctenocephalides felis damarensis), the cosmopolitan species Ctenocephalides canis and the African species Ctenocephalides connatus. We confirm the ubiquity of the cat flea, representing 85% of all fleas collected (4357/5123). Using a multigene approach combining two mitochondrial (cox1 and cox2) and two nuclear (Histone H3 and EF-1α) gene markers, as well as a cox1 survey of 516 fleas across 56 countries, we demonstrate out-of-Africa origins for the genus Ctenocephalides and high levels of genetic diversity within C. felis. We define four bioclimatically limited C. felis clusters (Temperate, Tropical I, Tropical II and African) using maximum entropy modelling. This study defines the global distribution, African origin and phylogenetic relationships of global Ctenocephalides fleas, whilst resolving the taxonomy of the C. felis subspecies and related taxa. We show that humans have inadvertently precipitated the expansion of C. felis throughout the world, promoting diverse population structure and bioclimatic plasticity. By demonstrating the link between the global cat flea communities and their affinity for specific bioclimatic niches, we reveal the drivers behind the establishment and success of the cat flea as a global parasite.     

Phylogeography of the component species of broad-leaved evergreen forests in Japan,based on chloroplast DNA variation

In order to elucidate the past distribution and colonization routes of broad-leaved evergreen (lucidophyllous) forests, we investigated the intraspecific phylogeographic patterns of lucidophyllous forests in Japan and surrounding areas. We selected 6 component species with a similar geographic distributions growing in Castanopsis-dominant forests. We defined possible important refugia during the glacial periods as the regions rich in rare haplotypes (with a frequency of 5% or less), or as regions rich in the number of common haplotypes (with a frequency of more than 5%). We then located the sites of refuge by comparing the intraspecific phylogeographic patterns among 6 component species of lucidophyllous forests with respect to these two parameters (i.e., haplotype uniqueness and the number of haplotypes). The following results were obtained during the course of this study: (1) rare haplotypes were distributed among islands around the main islands of Japan; (2) rare subtypes and the greatest numbers of common haplotypes were observed in Kyushu, a finding which agreed with fossilized pollen data demonstrative of the past existence of refugia in southern Kyushu; and (3) rare haplotypes were found on the Muroto Peninsula, and the second greatest numbers of common haplotypes were observed on the Kii Peninsula, a finding which suggested the existence of additional important refugia along the Pacific coast of Japan during the glacial ages.     

Genetic and geographical differentiation of <Emphasis Type="Italic">Pandaka</Emphasis> gobies in Japan

The mitochondrial DNA (mtDNA) phylogeny of Japanese Pandaka species (Perciformes: Gobiidae) was inferred from partial nucleotide sequences of the mitochondrial 12S and 16S rRNA genes (1083bp). The resultant mtDNA tree showed two major clades (clade I and clade II), which were inconsistent with the present taxonomic classification. One of the major clades was further divided into two geographical groups, distributed on the Japanese Major Islands (clade I-A) and from Amami-oshima Island to Iriomote Island (clade I-B). The mtDNA haplotypes in clade II were found only on Iriomote Island. The mtDNA divergences in clade I indicated that the Japanese Major Island (clade I-A) and Ryukyu (clade I-B) groups have been geographically isolated from each other for millions of years, based on the putative molecular divergence rate. The geographical distributions of mtDNA haplotypes in clade I-A and clade I-B also suggested that Pandaka gobies had not dispersed to distant offshore islands, indicating that their geographical differentiation may be closely associated with the geological history of the Japanese and Ryukyu Archipelagos.This revised version was published online in January 2005 with corrections to the repetition of the 1st authors name.     

Molecular architecture of Pipistrellus pipistrellus/Pipistrellus pygmaeus complex (Chiroptera: Vespertilionidae): further cryptic species and Mediterranean origin of the divergence

Previous genetic analyses have demonstrated that two phonic types of one of the most common European bats, the Common pipistrelle, belong to distinct species, although they are almost identical morphologically (45 kHz Pipistrellus pipistrellus and 55 kHz Pipistrellus pygmaeus). To reconstruct the history of the species complex and explain the codistribution of both forms in Europe and the Mediterranean, we performed phylogenetic analysis based on a 402-bp portion of the cytochrome b gene. Particular attention was paid to the eastern and southern parts of the range where no data were available. We found further distinctive allopatric haplotypes from Libya and Morocco. The difference of about 6-7% described in the Libyan population suggests the occurrence of a new species in the southern Mediterranean. The species status of Moroccan population is also discussed. The phylogeographic patterns obtained and analysis of fossil records support the hypothesis of expansion of both species into Europe from the Mediterranean region during the Holocene. The allopatric speciation model fits our data best. The paleobiographic scenario envisaged is corroborated also by molecular clock estimations and correlations with Late Neogene environmental changes in the Mediterranean region which ended with the Messinian salinity crisis.     

Molecular phylogeography and systematics of the arid-zone members of the Egernia whitii (Lacertilia: Scincidae) species group

We assembled a molecular phylogeny for the arid-zone members of the Egernia whitii species group to test Pianka's [Zoogeography and speciation of Australian desert lizards: an ecological perspective, Copeia (1972) 127-145] hypothesis that habitat specificity to the three major arid-zone vegetation communities is the primary cause of lizard speciation within the arid interior of Australia. This hypothesis predicts that species should exhibit phylogeographic structuring concordant with the major arid-zone vegetation types. Sequence data were obtained from four of the five arid-zone members of the E. whitii species group, and from across the ranges of the ecologically generalized E. inornata and E. multiscutata and the more specialized E. striata. We targeted a fragment (696 base pair (bp)) of the mitochondrial genome comprising the 3' half of the ND4 gene. We analysed the data using parsimony, maximum likelihood and Bayesian methods. Our phylogeny confirms the monophyly of the arid-zone members of the species group, although the phylogenetic relationships among species were not fully resolved. Although our topology does not support the recognition of the existing subspecies within E. multiscutata, there is a substantial phylogeographic break between South Australian/Victorian (Clade 1) and Western Australian (Clade 2) populations. We found considerable phylogeographic structure within E. inornata, with six major clades identified. However, these clades were not concordant with the distribution of habitat types in the arid-zone. Phylogeographic structure was also observed in the more specialized E. striata, although our analysis revealed close phylogenetic affinities between the sympatric species E. striata and E. kintorei. Shimodaira-Hasegawa topology tests were equivocal in regard to whether the phylogeographic structure within E. striata was in accordance with Pianka's predictions. Although our data failed to provide strong support for the suggestion that ecological and habitat factors are responsible for the diversification of arid-zone lizards, most E. inornata and E. striata populations had similar habitats, indicating that adaptation to particular habitats may have some role in the speciation of lizards in the Australian arid-zone.     

Intraspecific sequence variation of chloroplast DNA among the component species of evergreen broad-leaved forests in Japan

For the purpose of phylogeographic study of lucidophyllous (evergreen broad-leaved) forests in Japan, we surveyed intraspecific chloroplast DNA (cpDNA) variation in 41 component species of such forests. Intraspecific cpDNA variations were detected in 14 species. In 15 species and one species group, 16 non-coding cpDNA regions were examined to find intraspecific sequence variation. The extent of variation in these regions was compared. The largest amount of intraspecific variation was detected in the rps16 region. A relatively large amount of intraspecific variation was detected in the petD-rpoA, rpl16, and trnL-F regions. It is suggested that these regions of cpDNA would be useful for detecting intraspecific variation in plant species, and could provide valuable information for various research purposes.