Phylogenetic and biogeographical relationships of the Sander pikeperches (Percidae: Perciformes): patterns across North America and Eurasia

North America and Eurasia share several closely related taxa that diverged either from the breakup of the Laurasian supercontinent or later closures of land bridges. Their modern population structures were shaped in Pleistocene glacial refugia and via later expansion patterns, which are continuing. The pikeperch genus Sander contains five species – two in North America (S. canadensis and S. vitreus) and three in Eurasia (S. lucioperca, S. marinus, and S. volgensis) – whose evolutionary relationships and relative genetic diversities were previously unresolved, despite their fishery importance. This is the first analysis to include the enigmatic and rare sea pikeperch S. marinus, nuclear DNA sequences, and multiple mitochondrial DNA regions. Bayesian and maximum‐likelihood trees from three mitochondrial and three nuclear gene regions support the hypothesis that Sander diverged from its sister group Romanichthys/Zingel ～24.6 Mya. North American and Eurasian Sander then differentiated ～20.8 Mya, with the former diverging ～15.4 Mya, congruent with North American fossils dating to ～16.3–13.6 Mya. Modern Eurasian species date to ～13.8 Mya, with S. volgensis being basal and comprising the sister group to S. lucioperca and S. marinus, which diverged ～9.1 Mya. Genetic diversities of the North American species are higher than those in Eurasia, suggesting fewer Pleistocene glaciation bottlenecks. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110 , 156–179.     

Phylogeny and diversification of the cloud forest Morpho sulkowskyi group (Lepidoptera,Nymphalidae) in the evolving Andes

The monophyletic Morpho sulkowskyi butterfly group, endemic of Andean cloud forests, was studied to test the respective contributions of Mio‐Pliocene intense uplift period and Pleistocene glacial cycles on Andean biodiversity. We sampled nine taxa covering the whole geographical range of the group. Two mitochondrial and two nuclear genes were analysed using a Bayesian method. We established a dated phylogeny of the group using a relaxed clock method and a wide‐outgroup approach. To discriminate between two hypotheses, we used a biogeographical probabilistic method. Results suggest that the ancestor of the M. sulkowskyi group originated during the Middle–Late Miocene uplift of the Eastern Cordillera in northern Peru. Biogeographical inference suggests that the M. sulkowskyi and Morpho lympharis clades diverged in the northern Peruvian Andes. The subsequent divergences, from the Late Miocene to the Late Pliocene, should have resulted from a dispersal towards the Northern Andes (M. sulkowskyi clade), after the closure of the West Andean Portal separating the Central and Northern Andes, and a southwards dispersal along the Peruvian and Bolivian Eastern Cordilleras (M. lympharis clade). Only a few divergences occurred at the very end of the Pliocene or during the Pleistocene, a period when the more recent uplifts interfered with Pleistocene glacial cycles.     

Ephemeral Pleistocene woodlands connect the dots for highland rattlesnakes of the Crotalus intermedius group

Aim To test how Pleistocene climatic changes affected diversification of the Crotalus intermedius species complex. Location Highlands of Mexico and the south‐western United States (Arizona). Methods We synthesize the matrilineal genealogy based on 2406 base pairs of mitochondrial DNA sequences, fossil‐calibrated molecular dating, reconstruction of ancestral geographic ranges, and climate‐based modelling of species distributions to evaluate the history of female dispersion. Results The presently fragmented distribution of the C. intermedius group is the result of both Neogene vicariance and Pleistocene pine–oak habitat fragmentation. Most lineages appear to have a Quaternary origin. The Sierra Madre del Sur and northern Sierra Madre Oriental are likely to have been colonized during this time. Species distribution models for the Last Glacial Maximum predict expansions of suitable habitat for taxa in the southern Sierra Madre Occidental and northern Sierra Madre Oriental. Main conclusions Lineage diversification in the C. intermedius group is a consequence of Pleistocene climate cycling. Distribution models for two sister taxa in the northern and southern Sierra Madre Occidental and northern Sierra Madre Oriental during the Last Glacial Maximum provide evidence for the expansion of pine–oak habitat across the Central Mexican Plateau. Downward displacement and subsequent expansions of highland vegetation across Mexico during cooler glacial cycles may have allowed dispersal between highlands, which resulted in contact between previously isolated taxa and the colonization of new habitats.     

Allopolyploid origin of Cardamine silana (Brassicaceae) from Calabria (southern Italy): karyological, morphological and molecular evidence

Endemic Cardamine silana from Calabria (southern Italy) previously reported to be related to C. raphanifolia was found to be hexaploid. Morphological characters and AFLP data were analysed to evaluate the degree of differentiation of C. silana from closely related taxa and to find parental taxa of this polyploid. Cardamine apennina from the C. pratensis group was examined as one putative parent, as indicated in previous studies of nuclear ITS sequences, along with other related taxa based on both cpDNA and ITS sequences. Both multivariate morphometric analyses of quantitative characters and evaluation of qualitative morphological characters showed: (1) closest position of C. silana to two diploids: C. acris from the Balkan Peninsula and C. apennina from Central Italy; (2) good extent of morphological separation of C. silana from related taxa; and (3) within C. acris subspecies, C. acris ssp. vardousiae from Central Greece as closest to C. silana . Neighbour-joining tree and PCoA ordinations of AFLP data, as well as patterns of AFLP bands sharing, corroborated results of multivariate morphometrics. This evidence supports an allopolyploid origin of C. silana , with C. apennina and C. acris as parental taxa. Its origin may be dated to Pleistocene glacial events, because of the presumably wider geographical distributions of its parental taxa during more humid periods at that time.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 148 , 101–116.     

Phylogeny and divergence time of island tiger beetles of the genus Cylindera (Coleoptera: Cicindelidae) in East Asia

To examine the diverse colonization histories in eight tiger beetle species of the genus Cylindera (Coleoptera: Cicindelidae) on the East Asian islands, we conducted phylogenetic analyses and divergence time estimation using mitochondrial cytochome oxidase subunit I (COI) and nuclear 28S rDNA sequences. The island fauna consisted of four subgenera: Apterodela, Cicindina, Ifasina, and Cylindera. Apterodela is a flightless group with large bodies, whereas the others are fliers with small bodies. In Apterodela, the divergence among endemic species in Taiwan, Japan, and the mainland was ancient (2.1–4.7 Mya), as expected from their flightlessness. Their dispersal might have occurred across the extended landmass in East Asia during the Pliocene. In the subgenus Cicindina, Cylindera elisae has spread throughout East Asia, from which an endemic species, Cylindera bonina, was derived on the oceanic Bonin Islands during the early Pleistocene (0.9 Mya). This indicates the significance of Cylindera bonina, which is currently confined to a single island, for conservation. In the subgenus Ifasina, Cylindera kaleea is widely distributed in East Asia, and its sister species Cylindera humerula, endemic to Okinawa Island, diverged 1.0 Mya, whereas Cylindera psilica on Taiwan and the Yaeyama Islands diverged approximately 0.8 Mya. In the subgenus Cylindera, the colonization of Cylindera gracilis in Japan from the mainland occurred during the last glacial period. With the exception of C. bonina, which likely colonized new territories by flight or drifting, other dispersal events might have used land connections that occurred repeatedly during the Pliocene and Pleistocene. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 715–727.     

Living in a tilted world: climate change and geography limit speciation in Old World anchovies (Engraulis; Engraulidae)

Historical changes in the distributions of temperate species in response to Milankovitch climate cycles have been well documented in palaeontological studies and recently evaluated with phylogeographical methods. How these cycles influence biological diversity remains a matter of debate. Molecular surveys of terrestrial and freshwater fauna demonstrate glacial refugia in low latitudes and range expansions into high latitudes, but few genetic studies have assessed the corresponding impact on marine fauna. In the present study, mtDNA sequences (N = 84) are surveyed to understand the impact of long‐term climate oscillations on ‘Old World’ anchovies (genus Engraulis), a monophyletic group occurring in north and south temperate zones of the eastern Atlantic and the western Pacific. The analysis of a 521‐bp sequence of mtDNA cytochrome b indicates a late Miocene or Pliocene dispersal from the north‐eastern Pacific (California–Mexico) to the north‐western Pacific (Japan), followed by Pleistocene dispersal from the north‐western Pacific to Europe. Geography mandates that populations in southern Africa and Australia were stepping‐stones for this dispersal. However, neither population occupies an intermediate position in the mtDNA genealogy; both populations are more recently derived from their northern neighbours. Haplotype diversity is high (h = 0.93–0.97) in European, Australian, and Japanese anchovies, but low (h = 0.22) in the southern African population, where all haplotypes are more closely related to European specimens than to each other. These southern populations occupy a precarious position, lacking north–south coastlines that allow range shifts during climatic extremes. Recurring extinctions and episodic recolonizations from northern hemisphere populations are the likely results. In this case, ocean‐climatic changes retard rather than enhance opportunities for evolutionary radiations. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 88 , 673–689.     

Strong genetic structuring without assortative mating or reduced hybrid survival in an onychophoran in the Tallaganda State Forest region,Australia

Genetic studies have revealed a large degree of previously unappreciated diversity in morphologically conserved taxa. To understand the implications of this phenomenon, studies investigating the processes responsible for generating and maintaining functional and neutral diversity within such taxa are needed. With this aim, patterns of differentiation across a contact zone between two catchment‐specific, and genetically and subtly morphologically distinguishable, races of the onychophoran Euperipatoides rowelli Reid, 1996 at the Tallaganda State Forest study system, Australia, were quantified using diagnostic body‐pattern differences, microsatellite markers, and the cytochrome c oxidase subunit I (COI) mitochondrial gene. These data were used to test whether hybridization occurred, and whether the reduced survival of hybrids compared with non‐hybrids and/or assortative mating were potentially important factors in retaining the divergence between these races, which probably arose during isolation in Pleistocene glacial refuges. It was found that hybrids at the focal contact zone do not have reduced embryo‐to‐adult survival compared with non‐hybrids, and that races apparently freely interbreed without substantial assortative mating, consistent with little or no cost to hybridization. Nonetheless, at their respective transect ends the races remain distinct. This phenomenon was attributed to the elevated location of the contact zone, which is likely to make it poor habitat for E. rowelli, and thus may restrict dispersal and gene flow. There was also tentative evidence for a relaxed selection against hybridization in the hybrid zone, and the relative importance of these two explanations will require separate investigation. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 589–602.     

Refugia within refugia – patterns in endemism and genetic divergence are linked to Late Quaternary climate stability in the Iberian Peninsula

In Europe, southern peninsulas served as major refugia during Pleistocene cold periods. However, growing evidence has revealed complex patterns of glacial survival within these southern regions, with multiple glacial refugia within each larger refugial area. We investigated the extent to which patterns of endemism and phylogeographic are concordant across animal species in the Iberian Peninsula, one of the most important unglaciated areas in Europe during the Pleistocene, can be explained in terms of climatic stability. We found that historical climatic stability (notably climate velocity measures integrating macroclimatic shifts with local spatial topoclimate gradients) was often among the most important predictors of endemic species richness for different taxonomic groups using models that also incorporated measures of modern climate. Furthermore, for some taxonomic groups, climatic stability was also correlated with patterns of spatial concordance in interpopulation genetic divergence across multiple taxa, and private haplotypes were more frequently found in relatively stable areas. Overall, our results suggest that both endemism patterns and cross‐taxa concordant phylogeographic patterns across the Iberian Peninsula to some extent are linked to spatial variation in Late Quaternary climate stability, in agreement with the proposed ‘refugia‐within‐refugia’ scenario. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 13–28.     

Phylogeography suggest the Yili Valley being the glacial refuge of the genus Ixiolirion (Amaryllidaceae) in China

The Pleistocene climatic oscillations had profound effects on the demographic history and genetic diversification of plants in arid north-west China where some glacial refugia have been recognized. The genus Ixiolirion comprises three species, of which two, I. tataricum and I. songaricum (endemic), occur in China. In some locations they are sympatric. We investigated their population structure and population history in response to past climatic change using a sample of 619 individuals in 34 populations with nITS and ptDNA sequences. A significant genetic divergence between the two species was supported by a high level of pairwise genetic differentiation, very low gene flow, and phylogenetic analysis showing that I. songaricum haplotypes were monophyletic, whereas those of I. tataricum were polyphyletic. We found significant differentiation and phylogeographic structure in both species. The split of the two species was dated to the late Miocene (～7?Ma), but deep divergence occurred in the mid-late Quaternary. A similar haplotype distribution pattern was found in both species: one to two dominant haplotypes across most populations, with unique haplotypes in a few populations or a geographic group. The genetic diversity, haplotype number, and haplotype diversity decreased from the Yili Valley to the central Tianshan and Barluk Mountains. Additionally, ptDNA analysis showed that I. tataricum diversified in the eastern Tianshan and Barluk Mountains, which might be due to physical barriers to long distance seed dispersal such as desert. In conclusion, our results indicated that the Yili Valley was likely a glacial refuge for Ixiolirion in China, with postglacial dispersal from the Yili Valley eastward to the eastern Tianshan Mountains, and northward to the Barluk Mountains. The climatic changes in the Miocene and Pleistocene and geographic barriers are important factors driving species divergence and differentiation of Ixiolirion and other taxa.     

Phylogenomics unravels Quaternary vicariance and allopatric speciation patterns in temperate‐montane plant species: A case study on the Ranunculus auricomus species complex

The time frame and geographical patterns of diversification processes in European temperate‐montane herbs are still not well understood. We used the sexual species of the Ranunculus auricomus complex as a model system to understand how vicariance versus dispersal processes in the context of Pleistocene climatic fluctuations have triggered speciation in temperate‐montane plant species. We used target enrichment sequence data from about 600 nuclear genes and coalescent‐based species tree inference methods to resolve phylogenetic relationships among the sexual taxa of the complex. We estimated absolute divergence times and, using ancestral range reconstruction, we tested if speciation was enhanced by vicariance or by dispersal processes. Phylogenetic relationships among taxa were fully resolved with some incongruence in the position of the tetraploid R. marsicus. Speciation events took place in a very short time at the end of the Mid‐Pleistocene Transition (830–580 thousand years ago [ka]). A second wave of intraspecific geographical differentiation occurred at the end of the Riss glaciation or during the Eemian interglacial between 200 and 100 ka. Ancestral range reconstruction suggests a widespread European ancestor of the R. auricomus complex. Vicariance has triggered allopatric speciation in temperate‐montane plant species during the climatic deterioration that occurred during the last phase of the Mid‐Pleistocene Transition. Vegetation restructuring from forest into tundra could have confined these forest species into isolated glacial macro‐ and microrefugia. During subsequent warming periods, range expansions of these species could have been hampered by apomictic derivatives and by other congeneric competitors in the same habitat.     

HOLARCTIC PHYLOGEOGRAPHY OF AN ASEXUAL SPECIES COMPLEX I. MITOCHONDRIAL DNA VARIATION IN ARCTIC DAPHNIA

Pleistocene glacial cycles undoubtedly altered the evolutionary trajectories of many taxa, yet few studies have examined the impact of such events on genetic differentiation and phylogeography at large geographic scales. Here we present the results of a circumarctic survey of mitochondrial DNA diversity in members of the Daphnia pulex complex. The analysis involved the survey of restriction site polymorphisms in a 2100-bp fragment of the NADH-4 (ND4) and NADH-5 (ND5) genes for 276 populations representing the two major groups (tenebrosa and pulicaria) in this complex across their Holarctic range. A comparison of the distribution patterns for seven clades in this complex revealed very clear phylogeographic structuring. Most notably, pulicaria group lineages were restricted primarily to the Nearctic, with some colonization of formerly glaciated portions of northern Europe. This group was not detected from vast expanses of northern Eurasia, including the Beringian glacial refuge. In contrast, tenebrosa group haplotypes showed considerable intercontinental divergence between Eurasian and North American lineages, but were absent from Greenland and Iceland, as well as the Canadian arctic archipelago. Dispersal in Eurasia was primarily in a westerly direction from Beringia, whereas dispersal in the Nearctic followed proglacial drainage patterns. Long-distance dispersal of certain lineages was observed in both groups, and variation in haplotype richness and nucleotide diversity allowed us to make inferences about the positioning of putative glacial refugia. Overall, the phylogeographic pattern of diversification in this arctic complex is characterized by the apparently unique postglacial histories for each clade, indicating that even closely allied taxa can respond independently to the allopatric effects of glacial cycles. This is in sharp contrast to other phylogeographic studies of species assemblages from more southern (unglaciated) latitudes, which are often characterized by concordant patterns.     

Population history of the terrestrial orchid Cremastra appendiculata var. variabilis from Korea,inferred from levels and distribution of genetic diversity

Cremastra appendiculata var. variabilis is a self‐compatible, insect‐pollinated, terrestrial orchid that is a typical member of the warm‐temperate vegetation in the Korean Peninsula. Here we examine levels and partitioning of allozyme diversity (22 loci) in 12 populations of this orchid to gain insight into its genetic structure and post‐glacial colonization history in Korea. It harboured considerably higher levels of genetic variation within populations (%P = 48.1, A = 1.70 and H_e = 0.217) and lower degree of differentiation among populations (F_ST = 0.068) than those typical of allozyme‐based studies in other terrestrial orchid species. These patterns suggest that extant populations were derived from multiple source populations (i.e. from multiple glacial refugia), although further studies are needed to confirm this scenario. In addition to population history, traits such as high potential of seed dispersal, a mixed mating system and its occurrence in large and continuous populations would have contributed to the current levels and distribution of genetic diversity in Korean populations of C. appendiculata var. variabilis. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 721–732.     

Genetic variation among Corsican and continental populations of the Eurasian treecreeper (Aves: Certhia familiaris) reveals the existence of a palaeoendemic mitochondrial lineage

In this study we investigated the phylogenetics of the Eurasian treecreeper (Certhia familiaris), a forest passerine with a wide Palaearctic range including Corsica, using three mitochondrial genes and three nuclear introns, and its phylogeographic history using the COI gene. Our phylogenetic results, including eight of the ten sub‐species currently recognized, support the monophyly of C. familiaris with respect to its Indo‐Asian sister species C. hodgsoni. C. familiaris comprises two lineages that diverged during the mid‐Pleistocene (c. 1 Myr): one palaeoendemic lineage has an allopatric range nowadays restricted to the Corsica island and the Caucasus region whereas the second one, more recent and widespread, is distributed over most of Eurasia and in northern China. The most likely scenario that may explain such a pattern is a double colonization of the western Palaearctic from the eastern range of the species. During the middle Pleistocene period, a first lineage expanded its range up into Europe but did not persist through glacial cycles except in Corsica and the Caucasus region. Later, during the upper Pleistocene, a second lineage began to diversify around 0.09 Myr, spreading towards the western Palaearctic from a unique refuge likely located in the eastern Palaearctic [correction added on 6 March 2015 after first online publication: 0.9 Myr amended to 0.09 Myr]. Apart from C. f. corsa, our results do not suggest any distinct evolutionary history for other sub‐species previously described on morphological grounds in Europe. Our study highlights the important conservation value of the Corsican treecreeper and emphasizes the major role of mature pine forests in the evolution of endemic bird taxa in Corsica. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 115 , 134–153.     

Phylogeography of Rhinichthys cataractae (Teleostei: Cyprinidae): pre‐glacial colonization across the Continental Divide and Pleistocene diversification within the Rio Grande drainage

The longnose dace, Rhinichthys cataractae, is a primary freshwater fish inhabiting riffle habitats in small headwater rivers and streams across the North American continent, including drainages east and west of the Continental Divide. The mitochondrially encoded cytochrome b gene (1140 bp) and 2298–2346 bp of the nuclear‐encoded genes S7 and RAG1 were obtained from 87 individuals of R. cataractae (collected from 17 sites throughout its range) and from several close relatives. Phylogenetic analyses recovered a monophyletic R. cataractae species‐group that contained Rhinichthys evermanni, Rhinichthys sp. ‘Millicoma dace’, and a non‐exclusive R. cataractae. Within the R. cataractae species‐group, two well‐supported lineages were identified, including a western lineage (containing R. evermanni, R. sp. ‘Millicoma dace’ and individuals of R. cataractae from Pacific slope drainages) and an eastern lineage (containing individuals of R. cataractae from Arctic, Atlantic, and Gulf slope drainages). Within the eastern lineage of R. cataractae, two well‐supported groups were recovered: a south‐eastern group, containing individuals from the Atlantic slope, southern tributaries to the Mississippi River, and the Rio Grande drainage; and a north‐eastern group, containing individuals from the Arctic slope and northern tributaries to the Mississippi River. Estimates of the timing of divergence within the R. cataractae species‐group, combined with ancestral area‐reconstruction methods, indicate a separation between the eastern and western lineages during the Pliocene to early‐Pleistocene, with a direction of colonization from the west of the Continental Divide eastward. Within the southern portion of its range, R. cataractae likely entered the Rio Grande drainage during the Pleistocene via stream capture events between the Arkansas River (Mississippi River drainage) and headwaters of the Rio Grande. A close relationship between populations of R. cataractae in the Rio Grande drainage and the adjacent Canadian River (Mississippi River drainage) is consistent with hypothesized stream capture events between the Pecos (Rio Grande drainage) and Canadian rivers during the late‐Pleistocene. The population of R. cataractae in the lower Rio Grande may have become separated from other populations in the Rio Grande drainage (upper Rio Grande and Pecos River) and Canadian River during the late‐Pleistocene, well before initiation of recent and significant anthropogenic disturbance within the Rio Grande drainage. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 317–333.     

Testing the role of the Himalaya Mountains as a dispersal barrier in freshwater gastropods (Gyraulus spp.)

The Himalayas are considered to constitute a biogeographical boundary between the Palaearctic and Oriental regions. However, this mountain range does not form a uniform barrier because several large river valleys deeply cut into the Himalayas, crossing drainage divides and potentially forming dispersal corridors, particularly for freshwater organisms. In the present study, the effectiveness of these corridors is tested for the first time based on molecular data, using the amphi‐Himalayan freshwater gastropod genus Gyraulus as a model group. Based on a broad spatial sampling from the Himalayas and the Tibetan Plateau, phylogenetic analyses were performed using mitochondrial DNA sequence data. The resulting phylogeny shows that northern and southern Himalayan clades are geographically distinct (i.e. they exclusively consist of either northern or southern specimens). This pattern suggests a lack of gene flow across the Himalayas probably at least since the late Pliocene/early Pleistocene. Successful dispersal and/or establishment of gastropods might have been impeded by geographical and ecological features. Instead of direct dispersal across the range, multiple colonizations of regions north and south of the Himalayas from extralimital areas have to be assumed. The Himalayas thus represent a very strong dispersal barrier for freshwater snails, and probably for other taxa as well. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 526–534.     

Phylogenetic analysis and differentiation of Veronica subgenus Stenocarpon in the Balkan Peninsula

The Balkan Peninsula is considered the most important refugium for species during the Pleistocene glaciations and today harbours c. 2000 endemic species, but we know surprisingly little about the evolution of taxa in this region. Veronica saturejoides, V. thessalica and V. erinoides are a group of closely related alpine taxa endemic to the Balkan Peninsula. Here, we analyse four DNA regions [the nuclear chalcone synthase intron (CHSi) and ribosomal internal transcribed spacer (ITS) region and the plastid rpoB‐trnC spacer and trnL‐trnL‐trnF region] and amplified fragment length polymorphism (AFLP) fingerprints to provide a phylogenetic hypothesis for the relationships among these taxa. Additionally, we analyse leaf morphological characters used to distinguish the three subspecies of V. saturejoides. The analyses support the distinction of the three subspecies based on previously intuitively suggested characters. Nuclear chalcone synthase intron data indicate that the southern taxa are genetically much more diverse than the more northern V. saturejoides subsp. saturejoides. Phylogenetic relationships inferred from this region and AFLP fingerprints support the monophyly of V. saturejoides. In contrast, plastid DNA regions suggest a closer relationship of V. saturejoides subsp. saturejoides to V. thessalica. The most likely scenario involves introgression into V. saturejoides subsp. saturejoides from V. thessalica. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 616–636.     

Speciation mirrors geomorphology and palaeoclimatic history in African laminate-toothed rats (Muridae: Otomyini) of the Otomys denti and Otomys lacustris species-complexes in the 'Montane Circle' of East Africa

We adopted an integrated systematic approach to delimit evolutionary species and describe phylogeographic, morphometric and ecological relationships in Otomys denti (from the Albertine Rift, Southern Rift in Malawi and the northern Eastern Arc Mountains) and Otomys lacustris (from the Southern Rift in Tanzania and Zambia, and the southern Eastern Arc Mountains). Molecular [cytochrome (cyt) b sequences, 1143 bp, N  = 18], craniometric (classical, N  = 100 and geometric, N  = 60) and ecological (Partial Least Squares regression of shape and ecogeographic variables) approaches show a profound, parallel disjunction between two groups: (1) Eastern Arc and Southern Rift (including the Malawi Rift) ( O. lacustris and Otomys denti sungae ) and (2) Albertine Rift ( Otomys denti denti and Otomys denti kempi ) taxa. Within both groups, cyt b sequences or craniometric analysis provided evidence for the differentiation of both southern and northern Eastern Arc from Southern Rift lineages (across the so-called Makambako Gap). Within the Albertine Rift ( denti – kempi ) lineage, populations from individual mountain ranges differed significantly in skull shape (but not size), but were similar genetically. Over-reliance in the past on very few morphological characters (e.g. number of molar laminae) and a polytypic species concept has obscured phylogenetic relationships and species discrimination in this group. We recognize at least three species in this group, and distinct lineages within two of these species. Each species or lineage was endemic to one of three regions: the Albertine Rift, the Malawi Rift or the Eastern Arc. Our result echo conclusions of recent studies of other mammalian and bird taxa and reflect the geomorphology and palaeoclimatic history of the region.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 913–941.     

Phylogeography of the prehensile-tailed skink Corucia zebrata on the Solomon Archipelago

The biogeography of islands is often strongly influenced by prior geological events. Corucia zebrata (Squamata: Scincidae) is endemic to the geologically complex Solomon Archipelago in Northern Melanesia. We examined the level of divergence for different island populations of C. zebrata and discussed these patterns in light of Pleistocene land bridges, island isolation, and island age. Corucia zebrata was sampled from 14 locations across the Solomon Archipelago and sequenced at two mitochondrial genes (ND2 and ND4; 1697 bp in total) and four nuclear loci (rhodopsin, an unknown intron, AKAP9, and PTPN12). Measures of genetic divergence, analyses of genetic variation, and Bayesian phylogenetic inference were used and the data assessed in light of geological information. Populations of C. zebrata on separate islands were found to be genetically different from each other, with reciprocal monophyly on mitochondrial DNA. Populations on islands previously connected by Pleistocene land bridges were marginally less divergent from each other than from populations on other nearby but isolated islands. There are indications that C. zebrata has radiated across the eastern islands of the archipelago within the last 1-4 million years. Nuclear loci were not sufficiently informative to yield further information about the phylogeography of C. zebrata on the Solomon Archipelago. Analyses of the mitochondrial data suggest that dispersal between islands has been very limited and that there are barriers to gene flow within the major islands. Islands that have been isolated during the Pleistocene glacial cycles are somewhat divergent in their mitochondrial genotypes, however, isolation by distance (IBD) and recent colonization of isolated but geologically younger islands appear to have had stronger effects on the phylogeography of C. zebrata than the Pleistocene glacial cycles. This contrasts with patterns reported for avian taxa, and highlights the fact that biogeographic regions for island species cannot be directly extrapolated among taxa of differing dispersal ability.     

Spatial distributions of European Tenebrionidae point to multiple postglacial colonization trajectories

Many studies have found that species richness in the Western Palaearctic follows a latitudinal trend, yet the importance of geographical and ecological factors in shaping species ranges remains obscure. In this article, we present geographical patterns of darkling beetles (Tenebrionidae), a species‐rich group of arthropods. We relate the spatial distributions of species, instead of simply species richness, to spatial and climatic gradients, and test the effects of area (by species–area relationships), latitude (by various climatic gradients) and environmental diversity (by elevation) using simultaneous autoregressive models to identify major correlates of species richness. We then use nestedness and co‐occurrence analyses to identify glacial refugial centres and postglacial dispersal trajectories responsible for current species ranges. Our results indicate the presence of two refugial centres (in the Iberian and Balkan peninsulas) that appear to have been particularly important in shaping extant tenebrionid ranges. Northern countries were selectively colonized by more tolerant and, possibly, more mobile species, which survived in southern refugia during the Pleistocene glacial maxima, whereas the low dispersal capabilities of many species that evolved in these southern isolated areas prevented their spread northwards. High levels of endemism recorded in Spain and Sardinia suggest that the faunas of these regions originated during the Tertiary period and have remained substantially isolated. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 318–329.     

Songs,genetics, and morphology: revealing the taxonomic units in the European Cicadetta cerdaniensis cicada group,with a description of new taxa (Hemiptera: Cicadidae)

Recent acoustic studies have revealed that Cicadetta montana (Scopoli, 1772), which was once thought to be a single widespread Palaearctic cicada species, is actually a complex of many taxa. Although some song patterns are very distinct, others comprise groups of closely related species, as in the case of Cicadetta cerdaniensis Puissant & Boulard, 2000, Cicadetta cantilatrix Sueur & Puissant, 2007, and Cicadetta anapaistica Hertach, 2011. Seven spatially or behaviourally isolated metapopulations belonging to this song group from Italy and Switzerland were detected and investigated using acoustic, molecular, and morphological methods. Taxonomic decisions in this group are challenging because of a lack of truly diagnostic morphological characters, variously coloured morphs, qualitatively intermediate song patterns in contact zones, and strong temperature dependence of song‐duration characters. Molecular genetic studies suggest rapid speciation resulting in incomplete lineage sorting and introgression. It is only by using multiple sources of data that species can be delimited. The new species C icadetta sibillae sp. nov. and the new subspecies C icadetta anapaistica lucana ssp. nov. were described using the microstructure of the male calling songs. C icadetta sibillae sp. nov. occurs from southern Switzerland to central Italy, and is the most abundant cicada in the Northern Apennine. C icadetta anapaistica lucana ssp. nov. is endemic to a small southern Italian distribution range, and seems to be threatened by habitat loss and fragmentation. There is strong evidence that current distribution patterns and phylogenetic relationships of the Cicadetta cerdaniensis group are linked to speciation events in Pleistocene glacial refugia in the Italian, Iberian, and Balkan peninsulas. © 2015 The Linnean Society of London