Distribution and population genetic structure of the Mediterranean pine shoot beetle Tomicus destruens in the Iberian Peninsula and Southern France

1 The Mediterranean pine shoot beetle Tomicus destruens has long been indistinguishable from its congeneric Tomicus piniperda. Both species attack pines, and can be found in sympatry. The geographical distribution of T. destruens is still unclear in most of the Mediterranean Basin. 2 We aimed to describe the geographical distribution and zones of sympatry of both species in the Iberian Peninsula and France, and to study the molecular phylogeographical pattern of T. destruens. 3 Tomicus spp. adults were sampled in Portugal, Spain and France, and a portion of the mitochondrial genes COI and COII was sequenced for 84 individuals. Sequences were aligned to a data set previously obtained from French localities. 4 Tomicus destruens was found in all populations, except for one locality in Portugal and in the Landes (France). It was in sympatry with T. piniperda in two locations on Pinus pinaster and one location on Pinus radiata. 5 Within‐population genetic diversity was high, but we found a significant pattern of spatial distribution of genetic variation, as well as a significant effect of the host tree. 6 The data suggest the existence of two glacial refugia, from which T. destruens recolonized its current range. One refugium was located in Portugal where the beetle probably evolved on P. pinaster. The corresponding haplotypes show a West–East frequency gradient. The other refugium was probably in the eastern range, where the beetles evolved on Pinus halepensis and P. pinea. The corresponding haplotypes show an East–West frequency gradient.     

Mitochondrial phylogeography of a Beringian relict: the endemic freshwater genus of blackfish Dallia (Esociformes)

Mitochondrial genetic variability among populations of the blackfish genus Dallia (Esociformes) across Beringia was examined. Levels of divergence and patterns of geographic distribution of mitochondrial DNA lineages were characterized using phylogenetic inference, median‐joining haplotype networks, Bayesian skyline plots, mismatch analysis and spatial analysis of molecular variance (SAMOVA) to infer genealogical relationships and to assess patterns of phylogeography among extant mitochondrial lineages in populations of species of Dallia. The observed variation includes extensive standing mitochondrial genetic diversity and patterns of distinct spatial segregation corresponding to historical and contemporary barriers with minimal or no mixing of mitochondrial haplotypes between geographic areas. Mitochondrial diversity is highest in the common delta formed by the Yukon and Kuskokwim Rivers where they meet the Bering Sea. Other regions sampled in this study host comparatively low levels of mitochondrial diversity. The observed levels of mitochondrial diversity and the spatial distribution of that diversity are consistent with persistence of mitochondrial lineages in multiple refugia through the last glacial maximum.     

Holarctic phylogeography of the testate amoeba Hyalosphenia papilio (Amoebozoa: Arcellinida) reveals extensive genetic diversity explained more by environment than dispersal limitation

Although free‐living protists play essential roles in aquatic and soil ecology, little is known about their diversity and phylogeography, especially in terrestrial ecosystems. We used mitochondrial cytochrome c oxidase subunit 1 (COI) gene sequences to investigate the genetic diversity and phylogeography of the testate amoeba morphospecies Hyalosphenia papilio in 42 Sphagnum (moss)‐dominated peatlands in North America, Europe and Asia. Based on ≥1% sequence divergence threshold, our results from single‐cell PCRs of 301 individuals revealed 12 different genetic lineages and both the general mixed Yule‐coalescent (GMYC) model and the automatic barcode gap discovery (ABGD) methods largely support the hypothesis that these 12 H. papilio lineages correspond to evolutionary independent units (i.e. cryptic species). Our data also showed a high degree of genetic heterogeneity within different geographical regions. Furthermore, we used variation partitioning based on partial redundancy analyses (pRDA) to evaluate the contributions of climate and dispersal limitations on the distribution patterns of the different genetic lineages. The largest fraction of the variation in genetic lineage distribution was attributed to purely climatic factors (21%), followed by the joint effect of spatial and bioclimatic factors (13%), and a purely spatial effect (3%). Therefore, these data suggest that the distribution patterns of H. papilio genetic lineages in the Northern Hemisphere are more influenced by climatic conditions than by dispersal limitations.     

Second Sahelian amphibian endemism suggested by phylogeography of Groove crowned Bullfrog (Hoplobatrachus occipitalis) in western Sahel and hints of polyploid species formation

Several studies have assessed the phylogeographic patterns of vertebrates in North Africa and Sahara–Sahel, but most of the phylogeographic knowledge on amphibians comes from the Mediterranean region while the southern Sahara and Sahel remain poorly studied. Here, we assess the phylogeography of the African Groove crowned frog Hoplobatrachus occipitalis, with a focus on western Sahel in order to better understand the biogeographic patterns of semi-aquatic species in this arid region. Using mitochondrial and nuclear markers, we have assessed the species’ genetic structure, distribution of genetic diversity, and the presence of cryptic diversity. We found evidence of a recent (re-)colonization of the mountains in its northernmost distribution, but also for the role of southern Mauritanian mountains and large rivers as refugia. Two major lineages were detected, one perhaps endemic to Mauritania and the other widespread in Africa. The first lineage possibly constitutes the second Sahelian amphibian endemic; the latter may have originated through an allopolyploidy event, with the Mauritanian lineage being one of the parental ones.     

Glacial refuges for three‐spined stickleback in the Iberian Peninsula: mitochondrial DNA phylogeography

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Intraspecific genetic structure,divergence and high rates of clonality in an amphi‐Atlantic starfish

Intraspecific genetic diversity and divergence have a large influence on the adaption and evolutionary potential of species. The widely distributed starfish, Coscinasterias tenuispina, combines sexual reproduction with asexual reproduction via fission. Here we analyse the phylogeography of this starfish to reveal historical and contemporary processes driving its intraspecific genetic divergence. We further consider whether asexual reproduction is the most important method of propagation throughout the distribution range of this species. Our study included 326 individuals from 16 populations, covering most of the species’ distribution range. A total of 12 nuclear microsatellite loci and sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene were analysed. COI and microsatellites were clustered in two isolated lineages: one found along the southwestern Atlantic and the other along the northeastern Atlantic and Mediterranean Sea. This suggests the existence of two different evolutionary units. Marine barriers along the European coast would be responsible for population clustering: the Almeria–Oran Front that limits the entrance of migrants from the Atlantic to the Mediterranean, and the Siculo‐Tunisian strait that divides the two Mediterranean basins. The presence of identical genotypes was detected in all populations, although two monoclonal populations were found in two sites where annual mean temperatures and minimum values were the lowest. Our results based on microsatellite loci showed that intrapopulation genetic diversity was significantly affected by clonality whereas it had lower effect for the global phylogeography of the species, although still some impact on populations’ genetic divergence could be observed between some populations.     

From Mediterranean shores to central Saharan mountains: key phylogeographical insights from the genus Myrtus

Aim The Mediterranean region is often regarded as a crossroads where species of various origins meet. However, the biogeographical relationships between this region and contiguous Saharan, Macaronesian and Irano‐Turanian regions have not been investigated in detail. The aim of this study was to characterize the phylogeography of the circum‐Mediterranean species Myrtus communis and to investigate the origin of isolated central Saharan populations of Myrtus nivellei. Location The distribution ranges of M. communis from Macaronesia to the Irano‐Turanian region (173 sampled populations) and of M. nivellei in the mountains (Hoggar, Tassili n’Ajjer, Immidir, Tibesti) of the central Sahara (23 populations). Methods Nuclear ribosomal DNA (nrDNA) sequences of Myrtaceae were used to root the phylogeny of Myrtus, and to date its crown node, according to a detailed review of the palaeobotanical records used for multiple fossil calibration. Chloroplast DNA (cpDNA) sequences were analysed through the determination of genetic diversity indices and by statistical phylogeography. Results Both cpDNA and nrDNA markers indicated east–west genetic differentiation within M. communis. During the late Miocene, a key vicariance event affected the previous circum‐Mediterranean distribution of Myrtus, leading to the isolation of eastern populations. During the late Miocene or early Pliocene, two clades diverged: one is now scattered in the Mediterranean Basin and adjacent regions, whereas the other evolved in the western Mediterranean region. The differentiation of lineages during the Plio‐Pleistocene occurred mainly in the western part of the Mediterranean Basin, which has been at the origin of migrations towards Macaronesian islands and Saharan mountains. This is one of the first plant phylogeographical studies to report migrations from the Mediterranean to the Sahara. Main conclusions The genus Myrtus has persisted in the Mediterranean region since at least the Neogene and its biogeography reflects the cumulation of the species’ responses to successive palaeoenvironmental changes. The current distribution of the genus Myrtus in the Mediterranean Basin and in isolated areas, such as the Macaronesian islands and Saharan mountains, can be explained by the striking ability of this plant not only to persist locally in various refugia, but also to migrate.     

The distribution of Quercus suber chloroplast haplotypes matches the palaeogeographical history of the western Mediterranean

Combining molecular analyses with geological and palaeontological data may reveal timing and modes for the divergence of lineages within species. The Mediterranean Basin is particularly appropriate for this kind of multidisciplinary studies, because of its complex geological history and biological diversity. Here, we investigated chloroplast DNA of Quercus suber populations in order to detect possible relationships between their geographical distribution and the palaeogeographical history of the western Mediterranean domain. We analysed 110 cork oak populations, covering the whole distribution range of the species, by 14 chloroplast microsatellite markers, among which eight displayed variation among populations. We identified five haplotypes whose distribution is clearly geographically structured. Results demonstrated that cork oak populations have undergone a genetic drift geographically consistent with the Oligocene and Miocene break-up events of the European-Iberian continental margin and suggested that they have persisted in a number of separate microplates, currently found in Tunisia, Sardinia, Corsica, and Provence, without detectable chloroplast DNA modifications for a time span of over 15 million years. A similar distribution pattern of mitochondrial DNA of Pinus pinaster supports the hypothesis of such long-term persistence, in spite of Quaternary climate oscillations and of isolation due to insularity, and suggests that part of the modern geographical structure of Mediterranean populations may be traced back to the Tertiary history of taxa.     

Pan‐African phylogeography of a model organism,the African clawed frog ‘Xenopus laevis’

The African clawed frog Xenopus laevis has a large native distribution over much of sub‐Saharan Africa and is a model organism for research, a proposed disease vector, and an invasive species. Despite its prominent role in research and abundance in nature, surprisingly little is known about the phylogeography and evolutionary history of this group. Here, we report an analysis of molecular variation of this clade based on 17 loci (one mitochondrial, 16 nuclear) in up to 159 individuals sampled throughout its native distribution. Phylogenetic relationships among mitochondrial DNA haplotypes were incongruent with those among alleles of the putatively female‐specific sex‐determining gene DM‐W, in contrast to the expectation of strict matrilineal inheritance of both loci. Population structure and evolutionarily diverged lineages were evidenced by analyses of molecular variation in these data. These results further contextualize the chronology, and evolutionary relationships within this group, support the recognition of X. laevis sensu stricto, X. petersii, X. victorianus and herein revalidated X. poweri as separate species. We also propose that portions of the currently recognized distributions of X. laevis (north of the Congo Basin) and X. petersii (south of the Congo Basin) be reassigned to X. poweri.     

High genetic diversity in southwest Asian populations of Philaenus spumarius (Hemiptera: Auchenorrhyncha)

The genus Philaenus is one of the best investigated among Auchenorrhyncha, and several morphological, ecological, karyological, and molecular data have led to a designation of up to 10 species, distributed mainly in the Mediterranean and south-western Asia. The only widespread Palaearctic species, P. spumarius, is known to be structured phylogeographically as it consists of two highly divergent mitochondrial clades (northeast, NE and southwest, SW), with several subclades. This study contributes to the species phylogeography through the study of the genetic diversity and affinity of P. spumarius populations from southwestern Asia. Mitochondrial DNA (cytochrome B) show a high level of genetic diversity within Turkish and Iranian populations, the majority of which belong to the SW clade, and only single populations from northeastern Turkey are found to be substantially highly divergent lineages within the NE clade. One of the NE populations also showed significant differences in the distribution and amount of heterochromatin compared to other populations. According to the results of this study and previous phylogenetic and phylogeographic works on this species, we conclude that Southwestern Asia is probably the place of origin of the Philaenus spumarius.     

Salinity appears to be the main factor shaping spatial COI diversity of Corbicula lineages within the Chinese Yangtze River Basin

Aim

To date, few studies have examined the phylogenetics of Corbicula clams in their native range and the environmental parameters influencing their distribution, although this could provide great insights into the biological adaptation and invasion dynamics of Corbicula clams. We sought to identify the genetic lineages of native Corbicula clams and elucidate the environmental factors shaping the distributions of identified lineages.

Location

China, mainly the Yangtze River Basin.

Methods

The alignment comprised 558 COI sequences including samples from China and 222 COI sequences from published studies. This dataset was used to generate phylogenetic trees and compare population diversity. We used dbRDA method to assess the relationship between these COI data and environmental factors measured to identify the important factors affecting Corbicula's distribution.

Results

The COI phylogenetic tree delineated the monophyly of 3 major COI clades and 77 distinct COI haplotypes in the Yangtze River Basin. The invasive lineage C/S (FW17) was not identified in our sampling in China, while invasive lineages A/R (FW5 = Hap6), B (FW1 = Hap17) and Rlc (FW4 = Hap43) were identified, abundant and widely distributed in the middle and lower reaches of Yangtze River. Focusing on populations from Yangtze River Basin, both the COI haplotype and nucleotide diversity in the lakes along the Yangtze River increased with longitude, except for the river mouth population. The AMOVA tests showed significant differentiation between the middle and lower reaches of the Yangtze River and among populations. The dbRDA results suggested that the parameter chloride explained most of the spatial COI haplotype distribution variation in the Yangtze River Basin, with the three invasive lineages tolerating broad fluctuations of salinity (chloride levels ranging from 4 to 60 mg/L).

Conclusions

The Corbicula COI haplotypes found within the Yangtze River Basin had distinct distribution preferences, with the invasive androgenetic lineages being the most abundant and widely distributed. Genetic diversity was higher in this native region than in invaded areas in Europe and America, while it decreased with increasing distance from the river mouth. Salinity appeared to be the main environmental factor shaping the COI haplotype distribution of Corbicula lineages within their native range.     

Historical biogeography of Mediterranean trout

Complete sequencing of the mitochondrial control region was used to describe phylogenetic relationships of brown trout populations (Salmo trutta) in the Mediterranean river basins of Iberia and to review the historical biogeography of trout from the Mediterranean regions. Phylogenetic relationships among trout lineages suggested that the Danubian one is the most ancestral, in accordance with the eastern origin of most of the European freshwater fish species. Nested-clade and mismatch analyses suggested that the present distribution of haplotypes of the Adriatic and Mediterranean lineages resulted from population expansions originated, respectively, from central and western Europe, which favoured extensive secondary contacts between lineages. Reduced diversity detected within 50% of the analysed populations and large intrabasin differentiation indicated restricted gene flow in post-glacial periods.     

Clonal diversity and geographic structure in <Emphasis Type="Italic">Pleurochaete squarrosa</Emphasis> (Pottiaceae): different sampling scale approach

This paper describes our investigation of genetic variation and clonal structure of the Mediterranean moss Pleurochaete squarrosa (Brid.) Lindb. (Pottiaceae), using inter-simple sequence repeat (ISSR) molecular markers and trnL_UAA (intron of plastid gene for Leu tRNA) sequence, choosing different sampling strategies and scales on 16 European populations. Moreover, the intercontinental distribution of two trnL haplotypes, previously found over a large area and including 24 populations in three continents, was also investigated. Despite the prevalent asexual reproduction, P. squarrosa shows a high level of genetic diversity. Some site features seem to affect the clonal structure at the local scale, influencing the relocation of detached fragments and the level of intermingling, but they do not substantially affect genetic diversity. The peculiar vegetative reproduction coupled with somatic mutation could partly account for the genetic variation detected. Genetic distances highlight geographic isolation and limited gene flow among populations. We found only two trnL haplotypes in Europe due to length polymorphism, but, over an intercontinental scale, only non-delete trnL was found in Africa and the USA. ISSR analysis within each population detected a higher genetic distance between the samples with different trnL haplotypes, suggesting the presence of two different genetic lineages within this species, geographically overlapping in the Mediterranean Basin.     

Divergent mitochondrial lineages arose within a large,panmictic population of the Savannah sparrow (Passerculus sandwichensis)

Unusual patterns of mtDNA diversity can reveal interesting aspects of a species’ biology. However, making such inferences requires discerning among the many alternative scenarios that could underlie any given mtDNA pattern. Next‐generation sequencing methods provide large, multilocus data sets with increased power to resolve unusual mtDNA patterns. A mtDNA‐based phylogeography of the Savannah sparrow (Passerculus sandwichensis) previously identified two sympatric, but divergent (~2%) clades within the nominate subspecies group and a third clade that consisted of birds sampled from northwest Mexico. We revisited the phylogeography of this species using a population genomic data set to resolve the processes leading to the evolution of sympatric and divergent mtDNA lineages. We identified two genetic clusters in the genomic data set corresponding to (a) the nominate subspecies group and (b) northwestern Mexico birds. Following divergence, the nominate clade maintained a large, stable population, indicating that divergent mitochondrial lineages arose within a panmictic population. Simulations based on parameter estimates from this model further confirmed that this demographic history could produce observed levels of mtDNA diversity. Patterns of divergent, sympatric mtDNA lineages are frequently interpreted as admixture of historically isolated lineages. Our analyses reject this interpretation for Savannah sparrows and underscore the need for genomic data sets to resolve the evolutionary mechanisms behind anomalous, locus‐specific patterns.     

Genetic characterization of brown trout (<Emphasis Type="Italic">Salmo trutta</Emphasis>) populations from the Southern Balkans using mtDNA sequencing and RFLP analysis

In the present study, a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was used to survey variation in a 1450-bp mitochondrial DNA (mtDNA) segment which comprises part of the cytochrome oxidase III (COIII) and ATPase subunit VI genes in 8 brown trout (Salmo trutta L) populations from the southern Balkans. In addition, a 300 bp fragment at the 5′ end of the control region was sequenced from representatives of the populations studied providing the opportunity to assign PCR-RFLP haplotypes into major phylogenetic lineages (i.e. Atlantic, Danubian, marmoratus, Adriatic and Mediterranean). The level of polymorphism found in the 1450 bp segment suggests that this PCR-RFLP assay may be useful for future diagnostic analyses of mitochondrial DNA in brown trout populations. A reduced within-population genetic variability but considerable among-population differentiation was observed. The results are in accordance with previous data on phylogeography of Mediterranean brown trout suggesting that mitochondrial DNA haplotypes are distributed in a mosaic pattern as a consequence of a complex evolutionary history. The present study shows that brown trout populations from the Southern Balkans are highly divergent and possess a unique genetic profile that should be taken into account when establishing conservation management programs. Handling editor: C. Sturmbauer     

Morphological and genetic identification of the three pine pests of the genus Tomicus (Coleoptera, Scolytidae) in Europe

Abstract

• 1 Morphological characters were elaborated and part of the mitochondrial COI gene was sequenced in order to facilitate the determination of the three European pine bark beetles Tomicus piniperda, T. destruens and T. minor. The sequence information also provided the first information on the phylogenetic and phylogeographical relationships of these species.
• 2 Three hair rows were found on the antennal club of T. destruens between the second and third suture. Tomicus piniperda had only one row. Three different hair types were detected on the elytra – two hair types were found on T. piniperda, whereas the third hair type was only detected on the elytra of T. destruens.
• 3 The COI region (445 bp) revealed high sequence divergence among T. destruens, T. piniperda and T. minor. The three species proved to be monophyletic species with 16.98–19.23% sequence divergence. A phylogenetic approach placed T. minor and T. destruens as sister taxa, which contradicts the morphological findings.
• 4 European populations of T. piniperda shared two haplotypes, indicating a homogenous distribution of the genotypes. In the American populations only one of these European haplotypes was found. The Greek, Italian and Spanish T. destruens populations revealed three population‐specific haplotypes, indicating restricted gene flow.
• 5 Species‐specific primers were designed to allow a rapid and definitive determination of the two sibling Tomicus species by PCR.

     

Mitochondrial haplotype variation and phylogeography of Iberian brown trout populations

The biogeographical distribution of brown trout mitochondrial DNA haplotypes throughout the Iberian Peninsula was established by polymerase chain reaction-restriction fragment polymorphism analysis. The study of 507 specimens from 58 localities representing eight widely separated Atlantic-slope (north and west Iberian coasts) and six Mediterranean drainage systems served to identify five main groups of mitochondrial haplotypes: (i) haplotypes corresponding to non-native, hatchery-reared brown trout that were widely distributed but also found in wild populations of northern Spain (Cantabrian slope); (ii) a widespread Atlantic haplotype group; (iii) a haplotype restricted to the Duero Basin; (iv) a haplotype shown by southern Iberian populations; and (v) a Mediterranean haplotype. The Iberian distribution of these haplotypes reflects both the current fishery management policy of introducing non-native brown trout, and Messinian palaeobiogeography. Our findings complement and extend previous allozyme studies on Iberian brown trout and improve present knowledge of glacial refugia and postglacial movement of brown trout lineages.     

A geographic mosaic of evolutionary lineages within the insular endemic newt Euproctus montanus

Islands are hotspots of biodiversity, with a disproportionately high fraction of endemic lineages, often of ancient origin. Nevertheless, intra‐island phylogeographies are surprisingly scarce, leading to a scanty knowledge about the microevolutionary processes induced on island populations by Plio‐Pleistocene climatic oscillations, and the manner in which these processes contributed to shape their current genetic diversity. We investigated the phylogeography, historical demography and species distribution models of the Corsican endemic newt Euproctus montanus (north‐western Mediterranean). As for many island endemics, the continuous distribution of E. montanus throughout its range has hitherto been considered as evidence for a single large population, a belief that also guided the species' categorization for conservation purposes. Instead, we found a geographic mosaic of ancient evolutionary lineages, with five main clades of likely Pliocene origin (2.6–5.8 My), all but one restricted to northern Corsica. Moreover, the copresence between main lineages in the same population was limited to a single case. As also suggested by growing literature on intra‐island phylogeographic variation, it seems that the extensive use of simplifying assumption on the population structure and historical demography of island populations—both in theoretical and applicative studies—should be carefully reconsidered, a claim that is well exemplified by the case presented here.     

Exceptional maternal lineage diversity in brown bears (Ursus arctos) from Turkey

The genetic diversity and phylogeography of maternal lineages in Ursus arctos Linnaeus, 1758 (the brown bear) have been studied extensively over the last two decades; however, sampling has largely been limited to the northern Holarctic, and was possibly biased towards lineages that recolonized the vast expanses of the north as the Last Glacial Maximum (LGM) ended. Here we report the genetic diversity and phylogeography of U. arctos from Turkey based on 35 non‐invasive samples, including five from captive individuals. Bayesian phylogenetic analyses based on a 269‐bp fragment of the mitochondrial DNA control region revealed 14 novel haplotypes belonging to three major lineages. The most widespread lineage was found to be the Eastern clade 3a, whereas geographically more restricted Western and Middle Eastern lineages were reported for the first time in Turkey. A specimen from the Taurus mountain range carried a haplotype closely related to the presumably extinct bears in Lebanon. Moreover, we identify a unique new lineage that appears to have split early within the Middle Eastern clade. Despite limited sampling, our study reveals a high level of mitochondrial diversity in Turkish U. arctos, shows that the ranges of both European and Middle Eastern clades extend into Turkey, and identifies a new divergent lineage of possibly wider historical occurrence. Obtaining these results with 35 samples also demonstrates the value of proper sampling from regions that have not been significantly affected by the LGM. © 2015 The Linnean Society of London     

Conservation genetics in hypersaline inland waters: mitochondrial diversity and phylogeography of an endangered Iberian beetle (Coleoptera: Hydraenidae)

Saline inland waters are globally threatened habitats harbouring many specialised endemic species, which often have restricted geographic ranges, and occur as highly isolated populations. We studied the genetic variation and phylogeography of Ochthebius glaber Montes and Soler, a rare and endangered water beetle endemic to hypersaline streams in the South and Southeast of the Iberian Peninsula. We used a 633 bp fragment of cytochrome oxidase subunit 1 gene to determine the genetic diversity and phylogeographic structure within this species, and interpret this in the light of the speciesȁ9 conservation requirements. Thirteen populations were sampled across the speciesȁ9 geographic range, and genetic diversity found to be very high, with 37 haplotypes across the 71 specimens examined (p-distance 0.2–7.3%, average 3.1±0.4). Phylogeographic analyses revealed a surprisingly high degree of geographical structure, detectable among populations separated by relatively short geographical distances, with three main groups of haplotypes which have apparently been isolated for significant periods of time. Past fragmentation and contiguous range expansion events were inferred as the main causes of the detected geographical associations of haplotypes. The establishment of independent evolutionary lineages as conservation units is particularly important for species inhabiting saline habitats such as O. glaber, which is endangered by habitat loss across most of its distribution. However, given the natural instability of hypersaline environments, the conservation of a network of populations and potential habitats would be necessary to enable the preservation of the process generating and maintaining the diversity of the species.