Out of Cuba: overwater dispersal and speciation among lizards in the Anolis carolinensis subgroup

Overwater dispersal and subsequent allopatric speciation contribute importantly to the species diversity of West Indian Anolis lizards and many other island radiations. Here we use molecular phylogenetic analyses to assess the contribution of overwater dispersal to diversification of the Anolis carolinensis subgroup, a clade comprising nine canopy-dwelling species distributed across the northern Caribbean. Although this clade includes some of the most successful dispersers and colonists in the anole radiation, the taxonomic status and origin of many endemic populations have been ambiguous. New mitochondrial and nuclear DNA sequences from four species occurring on small islands or island banks (Anolis brunneus, Anolis longiceps, Anolis maynardi, Anolis smaragdinus) and one species from the continental United States (A. carolinensis) are presented and analysed with homologous sequences sampled from related species on Cuba (Anolis allisoni and Anolis porcatus). Our analyses confirm that all five non-Cuban species included in our study represent distinct, independently evolving lineages that warrant continued species recognition. Moreover, our results support Ernest Williams's hypothesis that all of these species originated by overseas colonization from Cuban source populations. However, contrary to Williams's hypothesis of Pleistocene dispersal, most colonization events leading to speciation apparently occurred earlier, in the late Miocene-Pliocene. These patterns suggest that overwater dispersal among geologically distinct islands and island banks is relatively infrequent in anoles and has contributed to allopatric speciation. Finally, our results suggest that large Greater Antillean islands serve as centres of origin for regional species diversity.     

Phylogeography of the Microcoleus vaginatus (Cyanobacteria) from three continents--a spatial and temporal characterization

It has long been assumed that cyanobacteria have, as with other free-living microorganisms, a ubiquitous occurrence. Neither the geographical dispersal barriers nor allopatric speciation has been taken into account. We endeavoured to examine the spatial and temporal patterns of global distribution within populations of the cyanobacterium Microcoleus vaginatus, originated from three continents, and to evaluate the role of dispersal barriers in the evolution of free-living cyanobacteria. Complex phylogeographical approach was applied to assess the dispersal and evolutionary patterns in the cyanobacterium Microcoleus vaginatus (Oscillatoriales). We compared the 16S rRNA and 16S-23S ITS sequences of strains which had originated from three continents (North America, Europe, and Asia). The spatial distribution was investigated using a phylogenetic tree, network, as well as principal coordinate analysis (PCoA). A temporal characterization was inferred using molecular clocks, calibrated from fossil DNA. Data analysis revealed broad genetic diversity within M. vaginatus. Based on the phylogenetic tree, network, and PCoA analysis, the strains isolated in Europe were spatially separated from those which originated from Asia and North America. A chronogram showed a temporal limitation of dispersal barriers on the continental scale. Dispersal barriers and allopatric speciation had an important role in the evolution of M. vaginatus. However, these dispersal barriers did not have a permanent character; therefore, the genetic flow among populations on a continental scale was only temporarily present. Furthermore, M. vaginatus is a recently evolved species, which has been going through substantial evolutionary changes.     

Phylogeography of the Rhabditis (Pellioditis) marina species complex: evidence for long-distance dispersal, and for range expansions and restricted gene flow in the northeast Atlantic

Pinpointing processes that structure the geographical distribution of genetic diversity of marine species and lead to speciation is challenging because of the lack of obvious dispersal barriers and the likelihood of substantial (passive) dispersal in oceans. In addition, cryptic radiations with sympatric distributions abound in marine species, challenging the allopatric speciation mechanism. Here, we present a phylogeographical study of the marine nematode species complex Rhabditis ( Pellioditis ) marina to investigate processes shaping genetic structure and speciation. Rhabditis ( P .) marina lives on decaying macroalgae in the intertidal, and may therefore disperse over considerable distances. Rhabditis ( P .) marina consists of several cryptic species sympatrically distributed at a local scale. Genetic variation in the COI gene was screened in 1362 specimens from 45 locations around the world. Two nuclear DNA genes (ITS and D2D3) were sequenced to infer phylogenetic species. We found evidence for ten sympatrically distributed cryptic species, seven of which show a strong genetic structuring. A historical signature showed evidence for restricted gene flow with occasional long-distance dispersal and range expansions pre-dating the last glacial maximum. Our data also point to a genetic break around the British Isles and a contact zone in the Southern Bight of the North Sea. We provide evidence for the transoceanic distribution of at least one cryptic species (PmIII) and discuss the dispersal capacity of marine nematodes. The allopatric distribution of some intraspecific phylogroups and of closely related cryptic species points to the potential for allopatric speciation in R. ( P .) marina .     

Phylogeographic structure and cryptic speciation in the trans-Antarctic moss Pyrrhobryum mnioides

Abstract Many bryophyte species have distributions that span multiple continents. The hypotheses historically advanced to explain such distributions rely on either long-distance spore dispersal or slow rates of morphological evolution following ancient continental vicariance events. We use phylogenetic analyses of DNA sequence variation at three chloroplast loci ( atpB-rbcL spacer, rps4 gene, and trnL intron and 3'spacer) to examine these two hypotheses in the trans-Antarctic moss Pyrrhobryum mnioides. We find: (1) reciprocal monophyly of Australasian and South American populations, indicating a lack of intercontinental dispersal; (2) shared haplotypes between Australia and New Zealand, suggesting recent or ongoing migration across the Tasman Sea; and (3) reciprocal monophyly among Patagonian and neotropical populations, suggesting no recent migration along the Andes. These results corroborate experimental work suggesting that spore features may be critical determinants of species range. We use the mid-Miocene development of the Atacama Desert, 14 million years ago, to calibrate a molecular clock for the tree. The age of the trans-Antarctic disjunction is estimated to be 80 million years ago, consistent with Gondwanan vicariance, making it among the most ancient documented cases of cryptic speciation. These data are in accord with niche conservatism, but whether the morphological stasis is a product of stabilizing selection or phylogenetic constraint is unknown.     

Biogeography and systematics of endemic island damselflies: The Nesobasis and Melanesobasis (Odonata: Zygoptera) of Fiji

The study of island fauna has greatly informed our understanding of the evolution of diversity. We here examine the phylogenetics, biogeography, and diversification of the damselfly genera Nesobasis and Melanesobasis, endemic to the Fiji Islands, to explore mechanisms of speciation in these highly speciose groups. Using mitochondrial (COI, 12S) and nuclear (ITS) replicons, we recovered Garli ‐part maximum likelihood and Mrbayes Bayesian phylogenetic hypotheses for 26 species of Nesobasis and eight species/subspecies of Melanesobasis. Biogeographical patterns were explored using Lagrange and Bayes ‐Lagrange and interpreted through beast relaxed clock dating analyses. We found that Nesobasis and Melanesobasis have radiated throughout Fiji, but are not sister groups. For Nesobasis, while the two largest islands of the archipelago—Viti Levu and Vanua Levu—currently host two distinct species assemblages, they do not represent phylogenetic clades; of the three major groupings each contains some Viti Levu and some Vanua Levu species, suggesting independent colonization events across the archipelago. Our Beast analysis suggests a high level of species diversification around 2–6 Ma. Our ancestral area reconstruction (Rasp ‐Lagrange ) suggests that both dispersal and vicariance events contributed to the evolution of diversity. We thus conclude that the evolutionary history of Nesobasis and Melanesobasis is complex; while inter‐island dispersal followed by speciation (i.e., peripatry) has contributed to diversity, speciation within islands appears to have taken place a number of times as well. This speciation has taken place relatively recently and appears to be driven more by reproductive isolation than by ecological differentiation: while species in Nesobasis are morphologically distinct from one another, they are ecologically very similar, and currently are found to exist sympatrically throughout the islands on which they are distributed. We consider the potential for allopatric speciation within islands, as well as the influence of parasitic endosymbionts, to explain the high rates of speciation in these damselflies.     

PROVINCIALISM IN PLANKTON: ENDEMISM AND ALLOPATRIC SPECIATION IN AUSTRALIAN DAPHNIA

Zooplankton species are generally considered poor candidates for allopatric speciation because of their broad distributions and capabilities for long-distance dispersal. We examined the validity of this conclusion by determining both species distributions and the extent of gene frequency divergence in the Daphnia fauna of southeastern Australia, a mature landscape dominated by members of the carinata complex. Although delimitation of species boundaries was complicated by the prevalence of interspecific hybrids and variation in breeding systems, allozyme analysis of 187 populations indicated the presence of at least seven species. All of these species had restricted distributions, and several were narrowly endemic. Gene frequency divergence was often apparent between populations separated by only a few kilometers but was least prominent in species from inland areas. The extent of regional gene frequency shifts varied among species—two narrowly distributed (projecta, thomsoni) and one broadly distributed (carinata) species showed little divergence between sites, but two other common species (cephalata, longicephala) showed marked gene frequency shifts coincident with physiographic barriers. Together, the limited species distributions and regional gene-pool fragmentation suggest that allopatric speciation has played an important role in the origin of taxon diversity in the Daphnia carinata complex.     

The geographic scale of speciation in a marine snail with high dispersal potential

Aim We use the Stramonita haemastoma species complex (Muricidae) to investigate the geographic scale of speciation in a marine snail with a long pelagic larval duration (PLD) of 2–3 months and, consequently, high dispersal potential. We aim to: (1) delimit species within Stramonita, (2) discover the phylogenetic relationship among them, (3) map their distributions, and (4) infer the age and likely cause of speciation events. Location Tropical intertidal of the Atlantic and eastern Pacific Oceans. Methods We use one nuclear and two mitochondrial genes to construct a molecular phylogeny of the S. haemastoma species complex. We first test the monophyly of the genus and of the species complex, and then use statistical methods to delimit species within the complex. We incorporate information from museum collections and the literature to map distributions and to look for diagnostic morphological traits. We use fossils to date our phylogeny. Results The genus Stramonita is monophyletic and restricted to the tropical and warm‐temperate Atlantic and eastern Pacific oceans. The genus is composed of Stramonita delessertiana and six members of the S. haemastoma complex: S. haemastoma, Stramonita rustica, Stramonita floridana, Stramonita canaliculata, Stramonita biserialis and Stramonita brasiliensis (new species described herein). These species are supported by reciprocal monophyly in mitochondrial gene trees, together with independent evidence from morphology, distribution and the nuclear gene. The species are almost entirely allopatric, with only three instances of sympatry. Two species have unusually wide distributions, consistent with their long PLD; one of these is amphi‐Atlantic. Main conclusions Despite the long PLD of Stramonita, speciation has occurred within the Atlantic, both in response to barriers operating at the largest geographical scale (the width of Atlantic, but not the Amazon barrier) and at a smaller scale within the western Atlantic.     

From Europe to Africa and vice versa: evidence for multiple intercontinental dispersal in ribbed salamanders (Genus Pleurodeles)

Aim The intricate puzzle-like geography of the western Mediterranean is a product of long-term tectonic and orogenic events, supplemented by repeated climatic oscillations since the Pliocene. It offers numerous vicariance events that may be invoked to explain speciation in amphibians. We test for plausibility of two mutually exclusive Iberian–African vicariance hypotheses to explain the basal split within newts of the genus Pleurodeles: (1) the disconnection of the Betic arch c. 14 Ma and (2) the end of the Messinian salinity crisis 5.33 Ma. Location Specimens of P. waltl and P. poireti were sampled from 32 populations in Portugal, Spain, Morocco, Algeria and Tunisia. Methods Parts of three mitochondrial genes were sequenced (16S rRNA, cytochrome b, ATPase). Based on substitution rate constancy among lineages three different molecular clocks were calibrated to derive competing evolutionary scenarios for lineage evolution within Pleurodeles. Results One scenario was aligned with the dated fossil record and with historical events that are known to have enabled terrestrial faunal exchange between Europe and Africa. In Pleurodeles, such faunal exchange is more likely to have happened three times, resulting in the current pattern of species diversity and haplotype distribution: (1) following the disconnection of the Betic region from Iberia and connection of its southernmost part (present-day Rif Mountains) to Africa, c. 14 Ma; (2) closing of the Strait of Gibraltar prior to the Messinian salinity crisis, 5.59–5.33 Ma; (3) passive dispersal in recent times, caused by rafting on vegetation or inadvertent displacement by man. The results show that North African P. poireti populations comprise two distinct lineages; despite their geographical proximity, haplotype distribution within both lineages indicates totally different histories (range fragmentation vs. dispersal). Main conclusions Ribbed salamanders mainly evolved through allopatric speciation, driven by vicariance events. However, faunal exchange between Europe and Africa at the western end of the Mediterranean basin was linked to well-known events of physical contact between both continents. This sheds new light on the potential role of dispersal across marine barriers via rafting or even, presumably inadvertent, anthropogenic displacement for the initiation of speciation in amphibians.     

Phylogenetics and biogeography of the two‐wing flyingfish (Exocoetidae: Exocoetus)

Two‐wing flyingfish (Exocoetus spp.) are widely distributed, epipelagic, mid‐trophic organisms that feed on zooplankton and are preyed upon by numerous predators (e.g., tunas, dolphinfish, tropical seabirds), yet an understanding of their speciation and systematics is lacking. As a model of epipelagic fish speciation and to investigate mechanisms that increase biodiversity, we studied the phylogeny and biogeography of Exocoetus, a highly abundant holoepipelagic fish taxon of the tropical open ocean. Morphological and molecular data were used to evaluate the phylogenetic relationships, species boundaries, and biogeographic patterns of the five putative Exocoetus species. We show that the most widespread species (E. volitans) is sister to all other species, and we find no evidence for cryptic species in this taxon. Sister relationship between E. monocirrhus (Indo‐Pacific) and E. obtusirostris (Atlantic) indicates the Isthmus of Panama and/or Benguela Barrier may have played a role in their divergence via allopatric speciation. The sister species E. peruvianus and E. gibbosus are found in different regions of the Pacific Ocean; however, our molecular results do not show a clear distinction between these species, indicating recent divergence or ongoing gene flow. Overall, our phylogeny reveals that the most spatially restricted species are more recently derived, suggesting that allopatric barriers may drive speciation, but subsequent dispersal and range expansion may affect the distributions of species.     

Biological Invasions Across Spatial Scales: Intercontinental, Regional, and Local Dispersal of Cladoceran Zooplankton

The frequency of dispersal of invertebrates among lakes depends upon perspective and spatial scale. Effective passive dispersal requires both the transport of propagules and the establishment of populations large enough to be detected. At a global scale, biogeographic patterns of cladoceran zooplankton species suggest that effective dispersal among continents was originally rare, but greatly increased in the past century with expanded commerce. Genetic analysis allows some reconstruction of past dispersal events. Allozyme and mitochondrial DNA comparisons among New World and Old-World populations of several exotic cladocerans have provided estimates for likely source populations of colonists, their dispersal corridors, and timing of earlier dispersal events. Detecting the Old-World tropical exotic Daphnia lumholtzi early in its invasion of North America has allowed detailed analysis of its spatial spread. Twelve years of collection records indicate a rapid invasion of reservoirs in the United States, by both regional spread and long-distance jumps to new regions. Combining landscape features with zooplankton surveys from south-central US reservoirs revealed higher colonization rates of D. lumholtzi at lower landscape positions, a result which can be explained by either greater propagule load or by higher susceptibility of these downstream reservoirs. Because invaded reservoirs provide a source of propagules for nearby floodplain ponds, the rarity of this species in ponds suggests limitation by local environments. Such analyses of invading species over multiple spatial scales allow a better understanding of ecological processes governing invasion dynamics.     

Evolutionary divergence in freshwater insects with contrasting dispersal capacity across a sea of desert

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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.     

Dispersal and the transition to sympatry in vertebrates

Under allopatric speciation models, a key step in the build-up of species richness is population dispersal leading to the co-occurrence of previously geographically isolated forms. Despite its central importance for community assembly, the extent to which the transition from spatial segregation (allopatry or parapatry) to coexistence (sympatry) is a predictable process, or alternatively one governed by chance and the vagaries of biogeographic history, remains poorly understood. Here, we use estimated divergence times and current patterns of geographical range overlap among sister species to explore the evolution of sympatry in vertebrates. We show that rates of transition to sympatry vary predictably according to ecology, being faster in marine or strongly dispersive terrestrial clades. This association with organism vagility is robust to the relative frequency of geographical speciation modes and consistent across taxonomic scales and metrics of dispersal ability. These findings reject neutral models of dispersal assembly based simply on evolutionary age and are not predicted by the main alternative view that range overlap is primarily constrained by biotic interactions. We conclude that species differences in dispersal limitation are fundamental in organizing the assembly of ecological communities and shaping broad-scale patterns of biodiversity over space and time.     

Speciation below ground: Tempo and mode of diversification in a radiation of endogean ground beetles

Dispersal is a critical factor determining the spatial scale of speciation, which is constrained by the ecological characteristics and distribution of a species’ habitat and the intrinsic traits of species. Endogean taxa are strongly affected by the unique qualities of the below‐ground environment and its effect on dispersal, and contrasting reports indicate either high dispersal capabilities favoured by small body size and mediated by passive mechanisms, or low dispersal due to restricted movement and confinement inside the soil. We studied a species‐rich endogean ground beetle lineage, Typhlocharina, including three genera and more than 60 species, as a model for the evolutionary biology of dispersal and speciation in the deep soil . A time‐calibrated molecular phylogeny generated from >400 individuals was used to delimit candidate species, to study the accumulation of lineages through space and time by species–area–age relationships and to determine the geographical structure of the diversification using the relationship between phylogenetic and geographic distances across the phylogeny. Our results indicated a small spatial scale of speciation in Typhlocharina and low dispersal capacity combined with sporadic long distance, presumably passive dispersal events that fuelled the speciation process. Analysis of lineage growth within Typhlocharina revealed a richness plateau correlated with the range of distribution of lineages, suggesting a long‐term species richness equilibrium mediated by density dependence through limits of habitat availability. The interplay of area‐ and age‐dependent processes ruling the lineage diversification in Typhlocharina may serve as a general model for the evolution of high species diversity in endogean mesofauna.     

Molecular phylogeny and biogeography of the dung beetle genus Temnoplectron Westwood (Scarabaeidae: Scarabaeinae) from Australia's wet tropics

The landscape of the Australian Wet Tropics can be described as "islands" of montane rainforest surrounded by warmer or more xeric habitats. Historical glaciation cycles have caused expansion and contraction of these rainforest "islands" leading to consistent patterns of genetic divergence within species of vertebrates. To explore whether this dynamic history has promoted speciation in endemic and diverse groups of insects, we used a combination of mtDNA sequencing and morphological characters to estimate relationships and the tempo of divergence among Australian representatives of the dung beetle genus Temnoplectron. This phylogenetic hypothesis shares a number of well-supported clades with a previously published phylogenetic hypothesis based on morphological data, though statistical support for several nodes is weak. Sister species relationships well-supported in both tree topologies, and a tree obtained by combining the two data sets, suggest that speciation has mostly been allopatric. We identify a number of speciation barriers, which coincide with phylogeographic breaks found in vertebrate species. Large sequence divergences between species emphasize that speciation events are ancient (pre-Pleistocene). The flightless, rainforest species appear to have speciated rapidly, but also in the distant past.     

Contrasting patterns of diversification in a bird family (Aves: Gruiformes: Rallidae) are revealed by analysis of geospatial distribution of species and phylogenetic diversity

Geospatial patterns in the distribution of regional biodiversity reflect the composite processes that underpin evolution: speciation, dispersal and extinction. The spatial distribution and phylogeny of a globally widespread and species rich bird family (Rallidae) were used to help assess the role of large‐scale biogeographical processes in diversity and diversification. Here, we examine how different geostatistical diversity metrics enhance our understanding of species distribution by linking occurrence records of rail species to corresponding species level phylogeny. Tropical regions and temperate zones contained a large proportion of rail species richness and phylogenetic diversity whilst small islands in Australian, Oceanian and Oriental regions held the highest weighted and phylogenetic endemism. Our results suggest that habitat connectivity and dispersal were important ecological features in rail evolution and distribution. Spatial isolation was a significant driver of diversification where islands in Oceania were centres of neo‐endemism with recent multiple and independent speciation events and could be considered as nurseries of biodiversity. Palaeo‐endemism was mostly associated with older stable regions, so despite extensive long distance range shifting these areas retain their own ancient and distinct character. Madagascar was the major area of palaeo‐endemism associated with the oldest rail lineages and could be considered a museum of rail diversity. This implies a mixture of processes determine the current distribution and diversity of rail clades with some areas dominated by recent ‘in situ’ speciation while others harbour old diversity with ecological traits that have stood the test of time.     

The building of a biodiversity hotspot across a land-bridge in the Mediterranean

Many of the macroevolutionary processes that have shaped present-day phylogenetic patterns were caused by geological events such as plate tectonics and temporary land-bridges. The study of spatial patterns of phylogenetic diversity can provide insights into these past events. Here we focus on a western Mediterranean biodiversity hotspot located in the southern Iberian Peninsula and northwest Africa, two regions that are separated by the Strait of Gibraltar. We explore the spatial structure of the phylogenetic relationships within and across large-scale plant assemblages. Significant turnover in terminal lineages tends to occur between landmasses, whereas turnover in deep lineages tends to occur within landmasses. Plant assemblages in the western ecoregions of this hotspot tend to be phylogenetically overdispersed but are phylogenetically clustered on its eastern margins. We discuss our results in the light of potential scenarios of niche evolution (or conservatism) and lineage diversification. The significant turnover between landmasses suggests a common scenario of allopatric speciation that could have been facilitated by the intermittent joining of the two continents. This may have constituted an important stimulus for diversification and the emergence of this western Mediterranean biodiversity hotspot.     

Caribbean golden orbweaving spiders maintain gene flow with North America

The Caribbean archipelago offers one of the best natural arenas for testing biogeographic hypotheses. The intermediate dispersal model of biogeography (IDM) predicts variation in species richness among lineages on islands to relate to their dispersal potential. To test this model, one would need background knowledge of dispersal potential of lineages and their biogeographic patterns, which has been problematic as evidenced by our prior work on the Caribbean tetragnathid spiders. In order to investigate the biogeographic imprint of an excellent disperser, we study Trichonephila in the Americas. Trichonephila is a nephilid genus that contains globally distributed species known to overcome long, overwater distances. The results of our phylogenetic and population genetic analyses on T. clavipes suggest that populations over the Caribbean and North America maintain a lively gene flow. However, the single species status of T. clavipes over the entire New World is challenged by our species delimitation analyses. Combined with prior evidence from spider genera of different dispersal ability, these patterns coming from an excellent disperser (Trichonephila) that is species-poor and of a relatively homogenous genetic structure, support the IDM predictions.     

Cyclamen: time, sea and speciation biogeography using a temporally calibrated phylogeny

Aim The Mediterranean region is a species‐rich area with a complex geographical history. Geographical barriers have been removed and restored due to sea level changes and local climatic change. Such barriers have been proposed as a plausible mechanism driving the high levels of speciation and endemism in the Mediterranean basin. This raises the fundamental question: is allopatric isolation the mechanism by which speciation occurs? This study explores the potential driving influence of palaeo‐geographical events on the speciation of Cyclamen (Myrsinaceae), a group with most species endemic to the Mediterranean region. Cyclamen species have been shown experimentally to have few genetic barriers to hybridization. Location The Mediterranean region, including northern Africa, extending eastwards to the Black Sea coast. Methods A generic level molecular phylogeny of Myrsinaceae and Primulaceae is constructed, using Bayesian approximation, to produce a secondary age estimate for the stem lineage of Cyclamen. This estimate is used to calibrate temporally an infrageneric phylogeny of Cyclamen, built with nrDNA ITS, cpDNA trnL‐F and cpDNA rps16 sequences. A biogeographical analysis of Cyclamen is performed using dispersal–vicariance analysis. Results The emergence of the Cyclamen stem lineage is estimated at 30.1–29.2 Ma, and the crown divergence at 12.9–12.2 Ma. The average age of Cyclamen species is 3.7 Myr. Every pair of sister species have mutually exclusive, allopatric distributions relative to each other. This pattern appears typical of divergence events throughout the evolutionary history of the genus. Main conclusions Geographical barriers, such as the varying levels of the Mediterranean Sea, are the most plausible explanation for speciation events throughout the phylogenetic history of Cyclamen. The genus demonstrates distributional patterns congruent with the temporally reticulate palaeogeography of the Mediterranean region.     

Insights into Neogene Mediterranean biogeography based on phylogenetic relationships of mountain and lowland lineages of Narcissus (Amaryllidaceae)

Aim Our aims were: (1) to reconstruct the phylogenetic relationships of daffodils (Narcissus), focusing on the lowland subgenus Hermione and the mountain section Apodanthi; (2) to estimate the temporal setting of diversification; (3) to reconstruct the migration patterns of the lineages; and (4) to examine the microevolutionary differentiation of the wide‐ranging Narcissus tazetta group across the Mediterranean. Location The Mediterranean Basin. Methods Plastid (trnT–L, trnL–F and ndhF) sequences were obtained from 63 populations representing 23 species of Narcissus and combined with published data from 16 species. Phylogenetic relationships and dating were inferred by Bayesian analysis based on geological events and divergence estimates of closely related taxa. A dispersal–extinction–cladogenesis analysis was performed using maximum likelihood methods to infer ancestral geographical distributions, and phylogeographical reconstruction was performed using coalescence analysis. Results Subgenus Hermione is not recognized as a monophyletic group because two of the nine species were found to have a close relationship with the subgenus Narcissus. The results on section Apodanthi confirmed previous findings of its monophyly and phylogenetic relationships within this mountain group. Molecular dating and ancestral range reconstructions suggest that the ancestor of Narcissus originated in the Iberian Peninsula during the Late Oligocene–Early Miocene. Eastward expansion of the lineage range proceeded from the western Mediterranean and involved colonization of mountain ranges in northern Africa. The phylogeography of the N. tazetta group revealed a widespread distribution of certain haplotypes, suggesting wide dispersal and a high level of colonization in the Mediterranean Basin. Main conclusions Our study points to the role of three key historical events in Narcissus diversification: tectonic shifts of the Alboran domain in the western Mediterranean, the Messinian salinity crisis, and the onset of the Mediterranean climate followed by periods of repeated glaciation. Diversification of section Apodanthi probably resulted from allopatric speciation, while subgenus Hermione may have shown more sympatric speciation and high dispersal, despite the lack of apparent adaptations to long‐distance dispersal. This is best exemplified by the presence of both ancestral and recent haplotypes of N. tazetta across the Mediterranean.