Molecular phylogeny of relict-endemic <Emphasis Type="Italic">Liquidambar orientalis</Emphasis> Mill based on sequence diversity of the chloroplast-encoded <Emphasis Type="Italic">mat</Emphasis>K gene

The genetic diversity and evolutionary divergence in Liquidambar species and Liquidambar orientalis varieties were compared with respect to the matK gene. A total of 66 genotypes from 18 different populations were sampled in southwestern Turkey. The matK region, which is about 1,512 bp in length, was sequenced and studied. L. orientalis, L. styraciflua, and L. formosana had similar magnitude of nucleotide diversity, while L. styraciflua and L. acalycina possessed higher evolutionary divergence. The highest evolutionary divergence was found between L. styraciflua and eastern Asian Liquidambar species (0.0102). However, the evolutionary divergence between L. orientalis and other species was of a similar magnitude. The maximum-parsimony phylogenetic tree showed that L. styraciflua and L. orientalis formed a closer clade while East Asian species were in a separate clade. This suggests that the North Atlantic Land Bridge through southern Greenland may have facilitated continuous distribution of Liquidambar species from southeastern Europe to eastern North America in early Tertiary period. The maximum-parsimony tree with only 18 Oriental sweetgum populations indicated that there were two main clusters: one with mainly L. orientalis var. integriloba and the other with var. orientalis and undetermined populations. High nucleotide diversity (0.0028) and divergence (0.00072) were found in L. orientalis var. integriloba populations and Muğla-1 geographical region. This region could be considered as the major refugium and genetic diversity center for the species. The low genetic diversity and divergence at intraspecies level suggest that L. orientalis populations in Turkey share an ancestral polymorphism from which two varieties may have evolved.     

Differences between sympatric populations of <Emphasis Type="Italic">Eotetranychus carpini</Emphasis> collected from <Emphasis Type="Italic">Vitis vinifera</Emphasis> and <Emphasis Type="Italic">Carpinus betulus</Emphasis>: insights from host-switch experiments and molecular data

Eotetranychus carpini (Oudemans) is an important pest of grapevine (Vitis vinifera L.) in southern Europe. This mite is also found on a number of different plants, including Carpinus betulus L., which commonly occurs in stands and hedgerows bordering vineyards, where it may serve as a potential mite reservoir. The economic importance of this pest has motivated a number of studies aimed at investigating whether the mites found on V. vinifera and C. betulus are conspecific. The results obtained to date have been inconclusive. In this study, we used biological and molecular approaches to investigate this issue. First, we conducted host-switch experiments to test the ability of E. carpini to develop on an alternative host plant, using mite populations originally collected on either C. betulus or V. vinifera plants from the same area. Second, we investigated DNA-based differentiation using nucleotide sequences of the ITS1-5.8S-ITS2 region of the ribosomal DNA of individual E. carpini from the populations examined in our host-plant experiments. We also analyzed sequences of individuals collected in other regions (Italy and Slovenia) to estimate species variation. The results from our host-switch experiments suggest the differentiation of mites collected on the two hosts. Mites collected from C. betulus did not survive and reproduce on V. vinifera and vice versa. Our molecular work revealed significant genetic differentiation between the mites collected from the two hosts, but no evidence of genetic variation among specimens collected from the same host species. Our results indicate the existence of host races of E. carpini.     

Population genetic analysis of European Prunus spinosa (Rosaceae) using chloroplast DNA markers

Chloroplast DNA diversity in Prunus spinosa, a common shrub of European deciduous forests, was assessed using the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) technique. Thirty-two haplotypes were detected in 25 populations spread across the European continent. Ten haplotypes were shared by two or more populations, and 22 were private. The major proportion of the total cpDNA diversity (H(T) = 0.73) was located within the populations (H(S) = 0.49), and differentiation between populations was low (G(ST) = 0.33) compared with other forest species. Haplotype diversity was higher in southern Europe than in northern Europe, indicating probable localization of glacial refugia in southern Europe. The minimum-length spanning tree of haplotypes showed incongruency between the phylogeny of haplotypes and their geographic locations. This might be the result of intensive seed movements following recolonization, which thereby erased the phylogeographic structure in P. spinosa.     

Phylogeography, genetic diversity and conservation of the large copper butterfly Lycaena dispar in Europe

We argue that insect species conservation at large scales should take account of the distribution of genetic diversity among populations. Maintenance of genetic diversity may be vital in retaining a species' adaptive capacity and evolutionary potential. We illustrate the concept using the example of the large copper butterfly Lycaena dispar in Europe. This species has become extinct in parts of its range and is declining rapidly in others, whilst conversely, increasing in many areas. The latter has recently reduced its conservation status. Mitochondrial DNA analysis is used to construct a phylogeography from a preliminary sample set obtained from across Europe. A cytochrome b fragment of 402 base pairs was sequenced and 10 haplotypes were found. Relatedness among populations suggest that those from northern and central Europe are closely related and probably form one evolutionary significant unit (ESU) reflecting post-glacial colonization from southeast Europe. In contrast, the sample from Italy is divergent and should be considered a separate ESU. Our results, combined with ecological data, suggest that conservation action for this species should be targeted on specific regions and populations.     

Phylogeography and Pleistocene refugia of the Little Owl Athene noctua inferred from mtDNA sequence data

Pleistocene glaciations greatly affected the distribution of genetic diversity in animal populations. The Little Owl is widely distributed in temperate regions and could have survived the last glaciations in southern refugia. To describe the phylogeographical structure of European populations, we sequenced the mitochondrial cytochrome c oxidase I (COI) and control region (CR1) in 326 individuals sampled from 22 locations. Phylogenetic analyses of COI identified two deeply divergent clades: a western haplogroup distributed in western and northwestern Europe, and an eastern haplogroup distributed in southeastern Europe. Faster evolving CR1 sequences supported the divergence between these two main clades, and identified three subgroups within the eastern clade: Balkan, southern Italian and Sardinian. Divergence times estimated from COI with fossil calibrations indicate that the western and eastern haplogroups split 2.01–1.71 Mya. Slightly different times for splits were found using the standard 2% rate and 7.3% mtDNA neutral substitution rate. CR1 sequences dated the origin of endemic Sardinian haplotypes at 1.04–0.26 Mya and the split between southern Italian and Balkan haplogroups at 0.72–0.21 Mya, coincident with the onset of two Pleistocene glaciations. Admixture of mtDNA haplotypes was detected in northern Italy and in central Europe. These findings support a model of southern Mediterranean and Balkan refugia, with postglacial expansion and secondary contacts for Little Owl populations. Central and northern Europe was predominantly recolonized by Little Owls from Iberia, whereas expansion out of the Balkans was more limited. Northward expansion of the Italian haplogroup was probably prevented by the Alps, and the Sardinian haplotypes remained confined to the island. Results showed a clear genetic pattern differentiating putative subspecies. Genetic distances between haplogroups were comparable with those recorded between different avian species.     

Geographically congruent large‐scale patterns of plastid haplotype variation in the European herbs Silene dioica and S. latifolia (Caryophyllaceae)

The closely related dioecious herbs Silene latifolia and Silene dioica are widespread and predominantly sympatric in Europe. The species are interfertile, but morphologically and ecologically distinct. A study of large‐scale patterns of plastid DNA (polymerase chain reaction–restriction fragment length polymorphism) haplotypes in a sample of 198 populations from most of the European ranges of both species revealed extensive interspecific haplotype sharing. Four of the 28 detected haplotypes were frequent (found in > 40 populations) and widespread. Three of these frequent haplotypes occurred in both species and the geographic distribution of each haplotype was broadly congruent in both species. Each of these three, shared and widespread haplotypes is likely to have colonized central and/or northern Europe after the last glaciation from one or more of refugial areas in southern Europe. Interspecific hybridization and plastid introgression within refugial regions and/or during the early stages of postglacial expansion is the most plausible explanation for the broadly similar distribution patterns of the shared, frequent chloroplast haplotypes in the two species. The fourth frequent, widespread haplotype was absent from S. latifolia and almost entirely restricted to Nordic S. dioica. It is most likely that this haplotype spread into the Nordic countries from a central or northern European source or from a refugial area in Russia. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161 , 153–170.     

Stem anatomy of Rhipsalis (Cactaceae) and its relevance for taxonomy

We used paternally inherited chloroplast microsatellites (cpSSR) to study population genetic structure in the endemic and highly restricted Serbian spruce Picea omorika. Fragment size polymorphism at the five cpSSR regions that could be amplified out of the nine tested combined into only four different haplotypes in the seven populations studied. Mean total haplotypic diversity was H _T = 0.395, and mean within-population diversity was H _s = 0.279. Haplotypic variation was lower than in most conifers described so far and partitioned into two geographical groups. All northern P. omorika populations were fixed or nearly fixed for the common haplotype, while southern populations exhibited two to three haplotypes. We suggest that current P. omorika populations are shaped by extreme demographic bottleneck and random genetic drift linked to Quaternary glacial cycles. P. omorika thus belongs to the small group of genetically depauperate tree species.     

Phylogeography of Populus alba (L.) and Populus tremula (L.) in Central Europe: secondary contact and hybridisation during recolonisation from disconnected refugia

The central aim of this paper is to clarify the picture of postglacial recolonisation and the reconstruction of refugia of Populus alba (L.) and Populus tremula (L.) in the light of hybridisation of the two species. We focussed our study on Central and Southeastern Europe including reference samples from Spain, Sweden and Northern Africa.We investigated 414 individuals of 26 populations using restriction fragment length polymorphisms (PCR-RFLPs) in six maternally inherited chloroplast markers. Altogether, 57 haplotypes were analysed of which four indicated hybridisation events in the past. Phylogeographic structure was found for P. alba with low diversity in Eastern Europe versus high diversity in Italy and Central Europe. A lack of phylogeographic structure was assessed for P. tremula as expected for a boreal forest tree, and diversity was evenly distributed in the studied populations. Two main refugia were identified for P. alba in Italy and Romania. A previously described hybrid zone between species in Central Europe turned out also to be a zone of contact between southern and eastern chloroplast lineages in P. alba. In contrast, P. tremula recolonised its present habitats in Central Europe from several refugia near the former ice cap. We assume separate disconnected refugia for P. alba and P. tremula and suggest an immigration scenario involving the mixing of colonisation routes and interspecific introgression to be responsible for the observed patterns.     

Cryptic invasion in Southern Europe: The case of <Emphasis Type="Italic">Ferrissia fragilis</Emphasis> (Pulmonata: Ancylidae) Mediterranean populations

Four populations of the North American ancylid gastropod Ferrissia fragilis have been found in Southern Italy, thus expanding the known Eurasian distribution range of this invasive gastropod to the Mediterranean area. Both mitochondrial markers used for the molecular identification of the sampled specimens (16S and COI) showed a modest to absent haplotypic diversity in the studied Ferrissia populations from Europe and Asia, and their perfect identity with some of the haplotypes observed in North American F. fragilis populations. In the light of the scarce molecular diversity observed in the whole Palaearctic area and of the growing evidences for the ongoing spreading of the species in Europe, the occurrence of a single invasion event from North America possibly linked with aquarium plant trade followed by a rapid spreading of the species in Eurasia is suggested. The record of F. fragilis in Southern Italy caused some doubts on the presence of autochthonous Ferrissia populations in Europe and on the actual existence of Ferrissia wautieri. A molecular analysis of Ferrissia specimens from the loci typici of F. wautieri (Northern Italy) and F. clessiniana (Egypt) is definitely opportune.     

Phylogeny and genetic structure of the goitered gazelle (Artiodactyla,Bovidae) in north-western China indicated by the hypervariable mitochondrial control region

The goitered gazelle, Gazella subgutturosa, is a medium-sized ungulate inhabiting arid and semi-arid regions in the Middle East and central Asia. The intraspecific classification of the species remains unclear. We analysed the genetic diversity in mitochondrial DNA control region (CR) sequences (976?bp) from 104 wild samples from the Xinjiang Uyghur Autonomous Region (XUAR) in north-west China, and reconstructed phylogeny with additional sequences from across the species’ range. We detected 58 haplotypes in XUAR populations, all but three of which were specific to single sampling sites. The phylogenetic analysis displayed two obvious clades of mtDNA haplotypes and the other haplotypes differed from the two clades. A median-joining network showed three groups of haplotypes were to a high extent concordant with the phylogenetic tree. The haplotype clustering was consistent with their geographic distribution. Nei’s net sequence divergences amongst the three groups ranged from 0.010 to 0.018 and indicated three subspecies, two of which inhabit XUAR. We detected strong differentiation between northern (NX) and southern (SX) XUAR populations overall (F_ST?=?0.4448, P?相似文献   

Imprints of glacial refugia in the modern genetic diversity of Pinus sylvestris

Aim To understand the impact of glacial refugia and migration pathways on the modern genetic diversity of Pinus sylvestris. Location The study was carried out throughout Europe. Methods An extended set of data of pollen and macrofossil remains was used to locate the glacial refugia and reconstruct the migrating routes of P. sylvestris throughout Europe. A vegetation model was used to simulate the extent of the potential refugia during the last glacial period. At the same time a genetic survey was carried out on this species. Results The simulated distribution of P. sylvestris during the last glacial period is coherent with the observed fossil data, which showed a patchy distribution of the refugia between c. 40° N and 50° N. Several migrational fronts were detected within the Iberian and the Italian peninsulas, and outside the Hungarian plain and around the Alps. The modern mitochondrial DNA depicted three different haplotypes for P. sylvestris. Two distinct haplotypes were restricted to northern Spain and Italy, and the third haplotype dominated most of the present‐day remaining distribution range of P. sylvestris in Europe. Main conclusions During the last glacial period P. sylvestris was constrained under severe climatic conditions to survive in scattered and restricted refugial areas. Combining palaeoenvironmental data, vegetation modelling and the genetic data, we have shown that the long‐term isolation in the glacial refugia and the migrational process during the Holocene have played a major role in shaping the modern genetic diversity of P. sylvestris in Europe.     

DIFFERENTIATION OF MITOCHONDRIAL DNA POLYMORPHISMS IN POPULATIONS OF FIVE JAPANESE ABIES SPECIES

Mitochondrial DNA polymorphism of 40 populations of five Abies species was investigated using PCR-amplified coxI and coxIII gene probes. Using four combinations of probe and restriction enzyme, we detected three major haplotypes and 15 total haplotypes. We also found varied levels of gene diversity for the different species: 0.741, 0.604, 0.039, 0.000, and 0.292 for A. firma, A. homolepis, A. veitchii, A. mariesii, and A. sachalinensis, respectively. The marginal and southern populations of A. firma and A. homolepis have unique haplotypes, especially the Kyushu, Shikoku, and Kii Peninsula populations, which inhabit areas coinciding with probable refugia of the last glacial period and possess high levels of mtDNA genetic diversity. The haplotypes in some populations suggested mtDNA capture also occurred between species through introgression/hybridization. The strong mtDNA population differentiation in Abies is most likely due to the maternal inheritance of mitochondria and restricted seed dispersal. A phenetic tree based on the genetic similarity of the mtDNA suggests that some species are polyphyletic. Based on mtDNA variation, the five Abies species could be divided roughly into three groups: (1) A. firma and A. homolepis, (2) A. veitchii and A. sachalinensis, and (3) A. mariesii. However, we found that all these Abies species, except A. mariesii, are genetically very closely related according to an analysis of their cpDNA sequences. This showed that the chloroplast rbcL gene differed by only one base substitutions among the four species. We believe that the mtDNA variation and cpDNA similarity clearly reflect relationships among, and the dissemination processes affecting these Abies species since the last glacial period.     

Colonization routes of Pinus sylvestris inferred from distribution of mitochondrial DNA variation

Understanding the present-day distribution of molecular variation requires knowledge about the history of the species. Past colonization routes and locations of refugia of Scots pine (Pinus sylvestris) were inferred from variation in mitochondrial DNA in material collected from 37 populations located in countries within, and immediately adjacent to the continent of Europe. Two mitochondrial regions, nad1 intron (exon B/C) and nad7 intron 1, were included in the study. Differentiation in maternally inherited mitochondria was high (G _ST′ = 0.824). Two new haplotypes were found at the nad7 intron 1. The occurrence of a 5-bp indel variant was restricted to the Turkish Kalabak population and a 32 bp only found in Central, Eastern, and Northern Europe. The complete absence of the 32-bp indel from the Mediterranean peninsulas supports the view that coniferous forests existed outside these areas during the last glacial maximum, and these populations contributed to the subsequent colonization of the northern parts of Europe. P. sylvestris shares features of its glacial and postglacial history with two other northern, cold-tolerant tree species, Picea abies and Betula sp. These three species differ from many other European trees for which pollen core and molecular evidence indicate colonization from southern refugia after the last glacial period.     

Under the shadow of a big plane tree: Why Platanus orientalis should be considered an archaeophyte in Italy

In Italy, Platanus orientalis L. is judged as an endangered species by some authors and non-native by others: these contrasting assessments can mislead the prioritization of management actions to preserve the species and the riparian vegetation that is its host. Based on a multidisciplinary approach, including palaeobotanical and ecological information, we assessed its status in Italy including the ecological and conservation value of the riparian plant communities hosting it in the Cilento National Park (S-Italy). Palaeobotanical data showed that P. orientalis in Italy should be considered an archaeophyte. According to the ecological assessment of the riparian plant communities hosting P. orientalis, the presence of the species can be interpreted as an indicator of an unfavourable state for the conservation of riparian vegetation. Knowing the status of a species remains one of the first steps to take to correctly propose scientifically based solutions for the conservation of plant diversity. However, there are no absolute criteria for conservation because all conservation objectives can be considered as cultural values. In this context, P. orientalis should be protected as a symbolic tree, an archaeophyte testifying an ancient common Mediterranean cultural heritage, worthy of preservation but outside of natural habitats.     

Range wide versus local patterns of genetic diversity in hornbeam (<Emphasis Type="Italic">Carpinus betulus</Emphasis> L.)

A study based on AFLP markers was conducted to characterise the present population genetic structure of Carpinus betulus in Europe and to formulate guidelines for the use of this species in plantations on a local scale in Flanders. High within-population diversity and little (but significant) genetic differentiation were detected at both Flemish and European scales. However, there was a pattern of isolation by distance only at the European scale. Within-population gene diversity, a new rarefaction-based measure of number of genotypes (band richness) and percentage of polymorphic loci are lower north of major mountain chains, suggesting that the mountain ranges formed a second bottleneck for the hornbeam during postglacial recolonisation. In Flanders, despite lower gene diversity, there were more polymorphic loci than in other European populations, a pattern that might have been caused by the mixing of material through planting, e.g. in hedges. In view of these findings, it is advised to create a single Flemish seed zone and to use preferentially reproductive material from this seed zone for new plantations in Flanders.     

A new cryptic species of pond turtle from southern Italy, the hottest spot in the range of the genus Emys (Reptilia, Testudines, Emydidae)

Geographic variation in the mtDNA haplotypes (cytochrome b gene) of 127 European pond turtles from Italy was investigated. Thirty‐eight of the Italian samples were also studied by nuclear fingerprinting (ISSR PCR) and compared with samples from other parts of the range representing all nine currently known mtDNA lineages of Emys orbicularis. Our genetic findings were compared against morphological data sets (measurements, colour pattern) for 109 adult turtles from southern Italy. Italy is displaying on a small geographical scale the most complicated variation known over the entire distributional area of Emys (North Africa over Europe and Asia Minor to the Caspian and Aral Seas). The Tyrrhenic coast of the Apennine Peninsula, the Mt. Pollino area and Basilicata are inhabited by Emys orbicularis galloitalica, a subspecies harbouring a distinct mtDNA lineage. The same lineage is also found in Sardinia. Along the Adriatic coast of Italy and on the Salentine Peninsula (Apulia, southern Italy), another morphologically distinctive subspecies (Emys orbicularis hellenica) occurs, which also bears a different mtDNA lineage. A higher diversity of mtDNA haplotypes in the south of the Apennine Peninsula suggests that the glacial refugia of E. o. galloitalica and E. o. hellenica were located here. A further refuge of E. o. hellenica probably existed in the southern Balkans. The west coasts of the Balkans and Corfu have probably been colonized from Italy and not from the geographically closer southern Balkanic refuge. In Sicily, a third mtDNA lineage is distributed, which is sister to all other known lineages of Emys. Morphologically, Sicilian pond turtles resemble E. o. galloitalica. However, nuclear fingerprinting revealed a clear distinctiveness of the Sicilian taxon, whereas no significant divergence was detected between representatives of the other eight mtDNA lineages of Emys. Furthermore, nuclear fingerprinting provided no evidence for current or past gene flow between the Sicilian taxon and the mainland subspecies of E. orbicularis. Therefore, Sicilian pond turtles are described here as a species new to science. Some populations in Calabria and on the Salentine Peninsula comprise individuals of different mtDNA lineages. We interpret this as a natural contact. However, we cannot exclude that these syntopic occurrences are the result of human activity. For example, in other parts of Italy, the natural distribution pattern of Emys is obscured by allochthonous turtles. This could also be true for southern Italy. The discovery of the complex taxonomic differentiation in southern Italy requires reconsidering conservation strategies.     

Competition between Quercus petraea and Carpinus betulus in an ancient wood in England: seedling survivorship

Abstract. Age structures of populations of canopy trees in Wormley Wood are consistent with reports that successional change is occurring, with Carpinus betulus replacing Quercus petraea as the dominant species. TWINSPAN analysis of data from a vegetation survey identifies three communities (described in earlier work), the ‘Bracken’, ‘Bramble’, and‘Bareground’ societies, characterized by increasing prominence of C. betulus and loss of species diversity. An experiment was set up in which C. betulus, Q. petraea and Betula pendula seedlings were explanted into each of the communities. Survival of seedlings was monitored over 860 days and differences investigated. Cohort survivorship differed between species and sites. C. betulus seedlings survived longer than Q. petraea in Bracken and Bramble communities. Species- and site-specific variation in the types and effects of herbivory were found. Herbivory did not appear to be a critical factor in the survival of Q. petraea seedlings. The photosynthetic light response of the seedling species was measured in the field. The light compensation point for Q. petraea seedlings (77 μmol photon m^-2 s^-1) is higher than the maximum available light under the main tree canopies in the wood. In contrast, seedlings of C. betulus have a lower light compensation point (15 μmol photon m² s^-1) and the mature tree casts a deeper shade than Q. petraea. It is suggested that the invasion of the canopy by C. betulus, following the cessation of coppicing, is creating light levels too low for Q. petraea seedling banks to persist.     

Mitochondrial differentiation and biogeography of Hyla meridionalis (Anura: Hylidae): an unusual phylogeographical pattern

Aim To study the patterns of genetic variation and the historical events and processes that influenced the distribution and intraspecific diversity in Hyla meridionalis Boettger, 1874. Location Hyla meridionalis is restricted to the western part of the Mediterranean region. In northern Africa it is present in Tunisia, Algeria and Morocco. In south‐western Europe it is found in the south of France, north‐western Italy and north‐eastern and south‐western Iberian Peninsula. There are also insular populations, as in the Canaries and Menorca. Methods Sampling included 112 individuals from 36 populations covering the range of the species. We used sequences of mitochondrial DNA Cytochrome Oxidase I (COI) for the phylogeographical analysis (841 bp) and COI plus a fragment including part of tRNA lysine, ATP synthase subunits 6 and 8 and part of Cytochrome Oxidase III for phylogenetic analyses (2441 bp). Phylogenetic analyses were performed with paup *4.0b10 (maximum likelihood, maximum parsimony) and Mr Bayes 3.0 (Bayesian analysis). Nested clade analysis was performed using tcs 1.18 and Geo Dis 2.2. A dispersal‐vicariant analysis was performed with diva 1.0 to generate hypotheses about the geographical distribution of ancestors. Results We found little genetic diversity within samples from Morocco, south‐western Europe and the Canary Islands, with three well‐differentiated clades. One is distributed in south‐western Iberia and the High Atlas, Anti‐Atlas and Massa River in Morocco. The second is restricted to the Medium Atlas Mountains. The third one is present in northern Morocco, north‐eastern Iberia, southern France and the Canaries. These three groups are also represented in the nested clade analysis. Sequences from Tunisian specimens are highly divergent from sequences of all other populations, suggesting that the split between the two lineages is ancient. diva analysis suggests that the ancestral distribution of the different lineages was restricted to Africa, and that an explanation of current distribution of the species requires three different dispersal events. Main conclusions Our results support the idea of a very recent colonization of south‐western Europe and the Canary Islands from Morocco. South‐western Europe has been colonized at least twice: once from northern Morocco probably to the Mediterranean coast of France and once from the western coast of Morocco to southern Iberia. Human transport is a likely explanation for at least one of these events. Within Morocco, the pattern of diversity is consistent with a model of mountain refugia during hyperarid periods within the Pleistocene. Evaluation of the phylogenetic relationships of Tunisian haplotypes will require an approach involving the other related hylid taxa in the area.     

Species‐level phylogeographical history of the endemic species Calligonum roborovskii and its close relatives in Calligonum section Medusa (Polygonaceae) in arid north‐western China

Quaternary climatic oscillations appear to have influenced the genetic diversity and evolutionary history of arid‐adapted plants. To understand the processes involved and reveal evolutionary relationships, haplotypes were examined from Calligonum roborovskii, an endemic species occurring in the arid zones across the desert regions of north‐western China, and seven other species also from Calligonum section Medusa, including C. gobicum, C. mongolicum and the narrow endemic species C. ebi‐nuricum, C. pumilum, C. taklimakanense, C. trifarium and C. yengisaricum. Forty‐three haplotypes were identified in 422 individuals from 51 natural populations, from variation of two plastid DNA intergenic spacers (rpl32‐trnL and ycf6‐psbM). A high level of total genetic diversity was found across species for which more than two populations were examined, including C. gobicum, C. mongolicum, C. pumilum and C. roborovskii. A distinct isolation‐by‐distance pattern in each of these species was suggested by the Mantel test, indicating that restricted gene flow caused high genetic differentiation among populations. Three haplotypes were shared by two or three species each, but the other 40 haplotypes were species‐specific. The 43 haplotypes split into three major clades, but not species‐specific lineages; most of the Calligonum species were not reciprocally monophyletic, probably due to incomplete lineage sorting or introgression. The identified haplotypes were dated to 1.97 Mya (95% highest posterior density: 2.95–0.99 Mya) and diverged until the late Pleistocene, possibly linked to aridification and enlargement of deserts caused by climate changes. Variation of desert habitats during the Pleistocene might play a key role in causing the divergence.     

Phylogeography of the European brook lamprey (Lampetra planeri) and the European river lamprey (Lampetra fluviatilis) species pair based on mitochondrial data

The European river lamprey Lampetra fluviatilis and the European brook lamprey Lampetra planeri (Block 1784) are classified as a paired species, characterized by notably different life histories but morphological similarities. Previous work has further shown limited genetic differentiation between these two species at the mitochondrial DNA level. Here, we expand on this previous work, which focused on lamprey species from the Iberian Peninsula in the south and mainland Europe in the north, by sequencing three mitochondrial marker regions of Lampetra individuals from five river systems in Ireland and five in southern Italy. Our results corroborate the previously identified pattern of genetic diversity for the species pair. We also show significant genetic differentiation between Irish and mainland European lamprey populations, suggesting another ichthyogeographic district distinct from those previously defined. Finally, our results stress the importance of southern Italian L. planeri populations, which maintain several private alleles and notable genetic diversity.