Taxonomic revision and phylogenetic analysis of the flightless Mancallinae (Aves, Pan-Alcidae)

Although flightless alcids from the Miocene and Pliocene of the eastern Pacific Ocean have been known for over 100 years, there is no detailed evaluation of diversity and systematic placement of these taxa. This is the first combined analysis of morphological and molecular data to include all extant alcids, the recently extinct Great Auk Pinguinus impennis, the mancalline auks, and a large outgroup sampling of 29 additional non-alcid charadriiforms. Based on the systematic placement of Mancallinae outside of crown clade Alcidae, the clade name Pan-Alcidae is proposed to include all known alcids. An extensive review of the Mancallinae fossil record resulted in taxonomic revision of the clade, and identification of three new species. In addition to positing the first hypothesis of inter-relationships between Mancallinae species, phylogenetic results support placement of Mancallinae as the sister taxon to all other Alcidae, indicating that flightlessness evolved at least twice in the alcid lineage. Convergent osteological characteristics of Mancallinae, the flightless Great Auk, and Spheniscidae are summarized, and implications of Mancallinae diversity, radiation, and extinction in the context of paleoclimatic changes are discussed.     

The systematics of right whales (Mysticeti: Balaenidae)

Balaenidae (right whales) are large, critically endangered baleen whales represented by four living species. The evolutionary relationships of balaenids are poorly known, with the number of genera, relationships to fossil taxa, and position within Mysticeti in contention. This study employs a comprehensive set of morphological characters to address aspects of balaenid phylogeny. A sister‐group relationship between neobalaenids and balaenids is strongly supported, although this conflicts with molecular evidence, which may be an artifact of long‐branch attraction (LBA). Monophyly of Balaenidae is supported, and three major clades are recognized: (1) extinct genus Balaenula, (2) extant and extinct species of the genus Eubalaena, and (3) extant and extinct species of the genus Balaena plus the extinct taxon, Balaenella. The relationships of these clades to one another, as well as to the early Miocene stem balaenid, Morenocetus parvus, remain unresolved. Pliocene taxa, Balaenula astensis and Balaenula balaenopsis, form a clade that is the sister group to the Japanese Pliocene Balaenula sp. Eubalaena glacialis and Pliocene Eubalaena belgica, are in an unresolved polytomy with a clade including E. japonica and E. australis. Extant and fossil species of Balaena form a monophyletic group that is sister group to the Dutch Pliocene Balaenella, although phylogenetic relationships within Balaena remain unresolved.     

Pliocene–Pleistocene ecological niche evolution shapes the phylogeography of a Mediterranean plant group

Estimating species ability to adapt to environmental changes is crucial to understand their past and future response to climate change. The Mediterranean Basin has experienced remarkable climatic changes since the Miocene, which have greatly influenced the evolution of the Mediterranean flora. Here, we examine the evolutionary history and biogeographic patterns of two sedge sister species (Carex, Cyperaceae) restricted to the western Mediterranean Basin, but with Pliocene fossil record in central Europe. In particular, we estimated the evolution of climatic niches through time and its influence in lineage differentiation. We carried out a dated phylogenetic–phylogeographic study based on seven DNA regions (nDNA and ptDNA) and fingerprinting data (AFLPs), and modelled ecological niches and species distributions for the Pliocene, Pleistocene and present. Phylogenetic and divergence time analyses revealed that both species form a monophyletic lineage originated in the late Pliocene–early Pleistocene. We detected clear genetic differentiation between both species with distinct genetic clusters in disjunct areas, indicating the predominant role of geographic barriers limiting gene flow. We found a remarkable shift in the climatic requirements between Pliocene and extant populations, although the niche seems to have been relatively conserved since the Pleistocene split of both species. This study highlights how an integrative approach combining different data sources and analyses, including fossils, allows solid and robust inferences about the evolutionary history of a plant group since the Pliocene.     

Tempo and mode of hummingbird evolution

Lack of adequate historical data has hindered understanding of the evolutionary tempo and mode of many ecologically well-characterized avian radiations. DNA hybridization distances among 28 hummingbirds (Trochilidae) were used to establish a timescale for this family's radiation into more than 330 species. Under a variety of analytical assumptions, genetic distances calibrated with a fossil divergence date corrected for incompleteness in the geologic record indicated that all extant hummingbird lineages began to diverge in the Early Miocene, approximately 40 Myr (million years) after the Paleocene date estimated for the divergence of hummingbirds and swifts. The long period prior to the radiation of living forms provides ample time for divergent evolution to produce the large morphological gap that has tended to obscure the sister-relationship of hummingbirds and swifts. The Miocene radiation of extant hummingbird lineages itself began with the divergence of the hermit and nonhermit subfamilies approximately 17 Ma (million years ago), followed by the rapid divergence of two Andean and one principally Central and North American clade at approximately 12 Ma. Younger subsidiary lineages, including ones found mainly in the Andes or in North America, date to the later Miocene-earlier Pliocene, approximately 6 Ma. The DNA hybridization-based chronology thus indicates a protracted, rather than stricdy rapid, radiation. Evidence from a broader spectrum of organisms supports the general pattern that higher taxonomic structure within many extant continental families evolved in the Miocene, suggesting that a common environmental pacemaker initiated radiation in unrelated groups. Compared to those in the Pleistocene, radiations tracing to the Miocene may have depended less on rapid climate cycling than on creation of new habitats by major geologic and climatic upheavals. For extant hummingbirds, a principal cause for their Miocene diversification probably was the ability of the ecologically generalized subfamily of nonhermits to radiate in montane areas created by the Andean and other orogenies. Similar interactions between new habitats and their exploitation by ecological generalists may explain, at least in part, the contemporaneous radiation of Passeriformes, the most diverse avian order.     

High diversity Pleistocene rainforest Dasyurid assemblages with implications for the radiation of the dasyuridae

It is commonly accepted that dasyurids (Marsupialia: Dasyuridae) radiated in the late Miocene or early Pliocene in response to a drying trend in Australia's climate as evidenced from the high diversity of dasyurids from modern arid environments compared with Miocene rainforest assemblages. However, mid‐Pleistocene dasyurid assemblages from cave deposits at Mt Etna, Queensland are more diverse than any previously known from rainforest habitats. New taxa will be described elsewhere, but include three new genera as well as new species of Dasyurus, Antechinus and Phascogale. Comparison of dasyurids from Mt Etna sites that are interpreted as rainforest palaeoenvironments with fossil and extant assemblages indicate that they are at least as diverse as those from modern arid environments. Thus Neogene diversification of dasyurids occurred in both arid and rainforest habitats, but only the former survived continuing aridification. Hence, aridification cannot be invoked for the diversification of all dasyurid lineages.     

How lizards survived blizzards: phylogeography of the Liolaemus lineomaculatus group (Liolaemidae) reveals multiple breaks and refugia in southern Patagonia and their concordance with other codistributed taxa

Patagonia was shaped by a complex geological history, including the Miocene uplift of the Andes, followed by volcanism, marine introgressions, and extreme climatic oscillations during Pliocene–Pleistocene glaciation–deglaciation cycles. The distributional patterns and phylogenetic relationships of southern patagonian animals and plants were affected in different ways, and those imprints are reflected in the seven phylogeographic breaks and eight refugia that have been previously proposed. In this study, we estimated time‐calibrated phylogenetic/phylogeographic patterns in lizards of the Liolaemus lineomaculatus group and relate them to historical Miocene‐to‐Pleistocene events of Patagonia and the previously proposed phylogeographic patterns. Individuals from 51 localities were sequenced for the mitochondrial marker (cyt‐b) and a subsample of individuals from each mitochondrial lineage was sequenced for one nuclear (LDA12D) and one slow evolving mitochondrial gene (12S). Our analyses revealed strong phylogeographic structure among lineages and, in most cases, no signal of demographic changes through time. The lineomaculatus group is composed of three strongly supported clades (lineomaculatus, hatcheri and kolengh + silvanae), and divergence estimates suggested their origins associated with the oldest known Patagonian glaciation (7–5 Ma); subsequent diversification within the lineomaculatus clade coincided with the large Pliocene glaciations (~3.5 Ma). The lineomaculatus clade includes nine strongly genetically and geographically structured lineages, five of which are interpreted as candidate species. Our findings suggest that some Liolaemus lineages have persisted in situ, each of them in a different refugium, through several glaciation–deglaciation cycles without demographic fluctuations. We also summarize and update qualitative evidence of some shared phylogeographic breaks and refugia among plants, rodents and lizards.     

The timing of diversification within the most divergent parrot clade

The Strigopidae are an ancient parrot (Psittaciformes) family consisting of three extant species placed in two genera (Nestor, Strigops) and restricted to New Zealand. Their evolutionary history is clouded because the timing of divergence events within this family has variously been attributed to Pleistocene climate change or much earlier earth‐historic events. Here we examine new psittaciform DNA sequence data, and combine them with previously published sequences, to shed light on the poorly understood timing of diversification within the Strigopidae. Using calibrations indirectly derived from both psittaciform and non‐psittaciform fossils, our data indicate a Late Pliocene or Early Pleistocene (ca 1.2–3.6 mya) differentiation between the two Nestor species (kea and kaka), possibly in response to shifts in habitat distribution associated with sea level fluctuations. The unique, monotypic, nocturnal and flightless genus Strigops (kakapo) is shown to have diverged from the Nestor lineage probably ca 28–29 mya, coinciding with the potential Oligocene submergence of Zealandia when much of its landmass may have been fragmented into smaller islands, providing a setting for allopatric diversification.     

The Taxonomic and Evolutionary History of Fossil and Modern Balaenopteroid Mysticetes

Balaenopteroids (Balaenopteridae + Eschrichtiidae) are a diverse lineage of living mysticetes, with seven to ten species divided between three genera (Megaptera, Balaenoptera and Eschrichtius). Extant members of the Balaenopteridae (Balaenoptera and Megaptera) are characterized by their engulfment feeding behavior, which is associated with a number of unique cranial, mandibular, and soft anatomical characters. The Eschrichtiidae employ suction feeding, which is associated with arched rostra and short, coarse baleen. The recognition of these and other characters in fossil balaenopteroids, when viewed in a phylogenetic framework, provides a means for assessing the evolutionary history of this clade, including its origin and diversification. The earliest fossil balaenopterids include incomplete crania from the early late Miocene (7–10 Ma) of the North Pacific Ocean Basin. Our preliminary phylogenetic results indicate that the basal taxon, “Megaptera” miocaena should be reassigned to a new genus based on its possession of primitive and derived characters. The late late Miocene (5–7 Ma) balaenopterid record, except for Parabalaenoptera baulinensis and Balaenoptera siberi, is largely undescribed and consists of fossil specimens from the North and South Pacific and North Atlantic Ocean basins. The Pliocene record (2–5 Ma) is very diverse and consists of numerous named, but problematic, taxa from Italy and Belgium, as well as unnamed taxa from the North and South Pacific and eastern North Atlantic Ocean basins. For the most part Pliocene balaenopteroids represent extinct species and genera and reveal a greater degree of morphological diversity than at present. The Pleistocene record is very limited and, unfortunately, fails to document the evolutionary details leading to modern balaenopteroid species diversity. It is evident, however, that most extant species evolved during the Pleistocene. Morphological and molecular based phylogenies support two competing hypotheses concerning relationships within the Balaenopteroidea: (1) balaenopterids and eschrichtiids as sister taxa, and (2) eschrichtiids nested within a paraphyletic Balaenopteridae. The addition of fossil taxa (including a new Pliocene species preserving a mosaic of balaenopterid and eschrichtiid characters) in morphological and “total evidence” analyses, offers the potential to resolve the current controversy concerning the possible paraphyly of Balaenopteridae.     

Early hominin speciation at the Plio/Pleistocene transition

Over the last half-decade or so, there has been an explosion in the recognition of hominin genera and species. We now have the late Miocene genera Orrorin and Sahelanthropus, the mid Pliocene genus Kenyanthropus, three new Pliocene species of Australopithecus (A. anamensis, A. garhi and A. bahrelghazali) and a sub species of Ardipithecus (Ar. r. kadabba) to contend with. Excepting also the more traditional species allocated to Paranthropus, Australopithecus and early Homo we are approaching around 15 species over 5 million years (excluding hominin evolution over the last one million years). Can such a large number of hominin species be justified? An examination of extant hominid (Gorilla gorilla, Pan troglodytes, and Pan paniscus) anatomical variability indicates that the range of fossil hominin variability supports the recognition of this large number of fossil species. It is also shown that not all hominins are directly related to the emergence of early Homo and as such have become extinct. Indeed the traditional australopithecine species 'A'. anamensis, 'A'. afarensis and 'A'. garhi are considered here to belong to a distinct genus Praeanthropus. They are also argued not be hominins, but rather an as yet undefined hominid group from which the more derived hominins evolved. The first hominin is represented by A. africanus or a hominin very much like it. The Paranthropus clade is defined by a derived heterochronic condition of peramorphosis, associated with sequential progenesis (contraction of successive growth stages) in brain and dental development, but a mixture of peramorphic and paedomorphic features in its craniofacial anatomy. Conversely, Kenyanthropus and Homo both share a pattern of peramorphosis, associated with sequential hypermorphosis (prolongation of successive growth stages) in brain development, and paedomorphosis processes in cranial, facial and dental development. This suggests, that these two clades share an important synapomorphy not recognised in the parsimony analyses, suggesting that they may form a sister group relationship to the exclusion of Paranthropus. This highlights the need to re-interpret phylogenetic results in terms of function and development. The rapid speciation and extinction as argued here is in keeping with other fossil groups in Africa at the Plio/Pleistocene transition. This emphasises that we must approach the pre-australopithecines and hominins as part of the endemic African fauna, and not in isolation to the evolutionary and climatic processes that were operating all around them.     

Winter is coming: Miocene and Quaternary climatic shifts shaped the diversification of Western‐Mediterranean Harpactocrates (Araneae,Dysderidae) spiders

Past climatic shifts have played a major role in generating and shaping biodiversity. Quaternary glacial cycles are the better known examples of dramatic climatic changes endured by ecosystems in temperate regions. Although still a matter of debate, some authors suggest that glaciations promoted speciation. Here we investigate the effect of past climatic changes on the diversification of the ground‐dwelling spider genus Harpactocrates, distributed across the major mountain ranges of the western Mediterranean. Concatenated and species‐tree analyses of multiple mitochondrial and nuclear loci, combined with the use of fossil and biogeographic calibration points, reveal a Miocene origin of most nominal species, but also unravel several cryptic lineages tracing back to the Pleistocene. We hypothesize that the Miocene Climatic Transition triggered major extinction events in the genus but also promoted its subsequent diversification. Under this scenario, the Iberian mountains acted as an island‐like system, providing shelter to Harpactocrates lineages during the climate shifts and favouring isolation between mountain ranges. Quaternary glacial cycles contributed further to the diversification of the group by isolating lineages in peripheral refugia within mountain ranges. In addition, we recovered some unique biogeographic patterns, such as the colonization of the Alps and the Apennines from the Iberian Peninsula.     

Comparative historical biogeography of Plateumaris leaf beetles (Coleoptera: Chrysomelidae) in Japan: interplay between fossil and molecular data

Aim In an attempt to use molecular and fossil data interactively in historical biogeography, we studied the phylogeography of five Plateumaris leaf beetles in Japan using mitochondrial cytochrome oxidase subunit I (COI) sequence data to explore interspecific differences in phylogeographical patterns and estimate the timings of colonization and geographical differentiation. Location A total of 461 beetles from five species on Hokkaido, Honshu and Kyushu islands of Japan were analysed with 117 beetles from three conspecies and two congeners from the mainland (Russia, including Sakhalin; Korea; Mongolia; Belgium; France; hereafter, the continent). Methods Using the sequence data from a 750‐bp portion of the COI gene, we studied the phylogeny of COI haplotypes, intraspecific population differentiation using analysis of molecular variance and the Mantel test, and intraspecific phylogeography using nested clade analysis. In addition, divergence times between the continental and Japanese lineages, as well as among the various Japanese lineages, were estimated using a Bayesian approach with node constraints based on fossil records of extant species. Results Three widely distributed species showed different degrees of geographical differentiation corresponding to their different colonization history in Japan. Bayesian estimates of divergence time revealed that one of two endemic species, which originated before the late Pliocene, attained intraspecific differentiation through the Pliocene and Pleistocene, whereas another endemic species has been confined in one locality, and three non‐endemic species colonized Japan after the mid‐Pleistocene. Main conclusions Molecular analyses of an insect group with relatively abundant fossil data can contribute greatly to the understanding of diverse biogeographical histories of related species in a region. Bayesian estimates of divergence time could be used to assess the variable evolutionary rates of the COI gene, and may be applied to other related insect species.     

THE EARLY DIVERSIFICATION HISTORY OF DIDELPHID MARSUPIALS: A WINDOW INTO SOUTH AMERICA'S “SPLENDID ISOLATION”

The geological record of South American mammals is spatially biased because productive fossil sites are concentrated at high latitudes. As a result, the history of mammalian diversification in Amazonia and other tropical biomes is largely unknown. Here we report diversification analyses based on a time‐calibrated molecular phylogeny of opossums (Didelphidae), a species‐rich clade of mostly tropical marsupials descended from a Late Oligocene common ancestor. Optimizations of habitat and geography on this phylogeny suggest that (1) basal didelphid lineages inhabited South American moist forests; (2) didelphids did not diversify in dry‐forest habitats until the Late Miocene; and (3) most didelphid lineages did not enter North America until the Pliocene. We also summarize evidence for an Early‐ to Middle‐Miocene mass extinction event, for which alternative causal explanations are discussed. To the best of our knowledge, this study provides the first published molecular‐phylogenetic evidence for mass extinction in any animal clade, and it is the first time that evidence for such an event (in any plant or animal taxon) has been tested for statistical significance. Potentially falsifying observations that could help discriminate between the proposed alternative explanations for didelphid mass extinction may be obtainable from diversification analyses of other sympatric mammalian groups.     

Age and historical biogeography of the pantropically distributed Spathelioideae (Rutaceae,Sapindales)

Aim The family Rutaceae (rue family) is the largest within the eudicot order Sapindales and is distributed mainly in the tropical and subtropical regions of both the New World and the Old World, with a few genera in temperate zones. The main objective of this study is to present molecular dating and biogeographical analyses of the subfamily Spathelioideae, the earliest branching clade (which includes eight extant genera), to interpret the temporal and spatial origins of this group, ascertaining possible vicariant patterns and dispersal routes and inferring diversification rates through time. Location Pantropics. Methods A dataset comprising a complete taxon sampling at generic level (83.3% at species level) of Spathelioideae was used for a Bayesian molecular dating analysis (beast ). Four fossil calibration points and an age constraint for Sapindales were applied. An ancestral area reconstruction analysis utilizing the dispersal–extinction–cladogenesis model and diversification rate analyses was conducted. Results Dating analyses indicate that Rutaceae and Spathelioideae are probably of Late Cretaceous origin, after which Spathelioideae split into a Neotropical and a Palaeotropical lineage. The Palaeotropical taxa have their origin inferred in Africa, with postulated dispersal events to the Mediterranean, the Canary Islands, Madagascar and Southeast Asia. The lineages within Spathelioideae evolved at a relatively constant diversification rate. However, abrupt changes in diversification rates are inferred from the beginning of the Miocene and during the Pliocene/Pleistocene. Main conclusions The geographical origin of Spathelioideae probably lies in Africa. The existence of a Neotropical lineage may be the result of a dispersal event at a time in the Late Cretaceous when South America and Africa were still quite close to each other (assuming that our age estimates are close to the actual ages), or by Gondwanan vicariance (assuming that our age estimates provide minimal ages only). Separation of land masses caused by sea level changes during the Pliocene and Pleistocene may have been triggers for speciation in the Caribbean genus Spathelia.     

Explosive Pleistocene range expansion leads to widespread Amazonian sympatry between robust and gracile capuchin monkeys

Aim Capuchin monkey species are widely distributed across Central and South America. Morphological studies consistently divide the clade into robust and gracile forms, which show extensive sympatry in the Amazon Basin. We use genetic data to test whether Miocene or Plio‐Pleistocene processes may explain capuchin species’ present distributions, and consider three possible scenarios to explain widespread sympatry. Location The Neotropics, including the Amazon and Atlantic Coastal Forest. Methods We sequenced the 12S ribosomal RNA and cytochrome b genes from capuchin monkey specimens. The majority were sampled from US museum collections and were wild‐caught individuals of known provenance across their distribution. We applied a Bayesian discrete‐states diffusion model, which reconstructed the most probable history of invasion across nine subregions. We used comparative methods to test for phylogeographic association and dispersal rate variation. Results Capuchins contained two well supported monophyletic clades, the morphologically distinct ‘gracile’ and ‘robust’ groups. The time‐tree analysis estimated a late Miocene divergence between Cebus and Sapajus and a subsequent Plio‐Pleistocene diversification within each of the two clades. Bayesian analysis of phylogeographic diffusion history indicated that the current wide‐ranging sympatry of Cebus and Sapajus across much of the Amazon Basin was the result of a single explosive late Pleistocene invasion of Sapajus from the Atlantic Forest into the Amazon, where Sapajus is now sympatric with gracile capuchins across much of their range. Main conclusions The biogeographic history of capuchins suggests late Miocene geographic isolation of the gracile and robust forms. Each form diversified independently, but during the Pleistocene, the robust Sapajus expanded its range from the Atlantic Forest to the Amazon, where it has now encroached substantially upon what was previously the exclusive range of gracile Cebus. The genus Cebus, as currently recognized, should be split into two genera to reflect the Miocene divergence and two subsequent independent Pliocene radiations: Cebus from the Amazon and Sapajus from the Atlantic Forest.     

A temporally dynamic approach for cladistic biogeography and the processes underlying the biogeographic patterns of North American deserts

We implemented a temporally dynamic approach to the cladistic biogeographic analysis of 13 areas of North American deserts and several plant and animal taxa. We undertook a parsimony analysis of paralogy‐free subtrees based on 43 phylogenetic hypotheses of arthropod, vertebrate and plant taxa, assigning their nodes to three different time slices based on their estimated minimum ages: Early‐Mid‐Miocene (23?7 Ma), Late Miocene/Pliocene (6.9?2.5 Ma) and Pleistocene (2.4?0.011 Ma). The analyses resulted in three general area cladograms, one for each time slice, showing different area relationships. They allowed us to detect influences of different geological and palaeoclimatological events of the Early‐Mid‐Miocene, Late Miocene/Pliocene and Pleistocene that might have affected the diversification of the desert biota. Several diversification events in the deserts of North America might have been driven by Neogene uplift, marine incursion and the opening of the California Gulf during the Miocene–Pliocene, whereas climatic fluctuations had the highest impact during the Pleistocene.     

Phylogenetic fields through time: temporal dynamics of geographical co-occurrence and phylogenetic structure within species ranges

Species co-occur with different sets of other species across their geographical distribution, which can be either closely or distantly related. Such co-occurrence patterns and their phylogenetic structure within individual species ranges represent what we call the species phylogenetic fields (PFs). These PFs allow investigation of the role of historical processes—speciation, extinction and dispersal—in shaping species co-occurrence patterns, in both extinct and extant species. Here, we investigate PFs of large mammalian species during the last 3 Myr, and how these correlate with trends in diversification rates. Using the fossil record, we evaluate species'' distributional and co-occurrence patterns along with their phylogenetic structure. We apply a novel Bayesian framework on fossil occurrences to estimate diversification rates through time. Our findings highlight the effect of evolutionary processes and past climatic changes on species'' distributions and co-occurrences. From the Late Pliocene to the Recent, mammal species seem to have responded in an individualistic manner to climate changes and diversification dynamics, co-occurring with different sets of species from different lineages across their geographical ranges. These findings stress the difficulty of forecasting potential effects of future climate changes on biodiversity.     

Reconstructing the demise of Tethyan plants: climate‐driven range dynamics of Laurus since the Pliocene

Aim Climate changes are thought to be responsible for the retreat and eventual extinction of subtropical lauroid species that covered much of Europe and North Africa during the Palaeogene and early Neogene; little is known, however, of the spatial and temporal patterns of this demise. Herein we calibrate ecological niche models to assess the climatic requirements of Laurus L. (Lauraceae), an emblematic relic from the Tethyan subtropical flora, subsequently using these models to infer how the range dynamics of Laurus were affected by Plio‐Pleistocene climate changes. We also provide predictions of likely range changes resulting from future climatic scenarios. Location The Mediterranean Basin and Macaronesian islands (Canaries, Madeira, Azores). Methods We used a maximum‐entropy algorithm (Maxent) to model the relationship between climate and Laurus distribution over time. The models were fitted both to the present and to the middle Pliocene, based on fossil records. We employed climatic reconstructions for the mid‐Pliocene (3 Ma), the Last Glacial Maximum (21 ka) and a CO₂‐doubling future scenario to project putative species distribution in each period. We validated the model projections with Laurus fossil and present occurrences. Results Laurus preferentially occupied warm and moist areas with low seasonality, showing a marked stasis of its climatic niche. Models fitted to Pliocene conditions successfully predicted the current species distribution. Large suitable areas existed during the Pliocene, which were strongly reduced during the Pleistocene, but humid refugia within the Mediterranean Basin and Macaronesian islands enabled long‐term persistence. Future climate conditions are likely to re‐open areas suitable for colonization north of the current range. Main conclusions The climatic requirements of Laurus remained virtually unchanged over the last 3 Myr. This marked niche conservatism imposed largely deterministic range dynamics driven by climate conditions. This species's relatively high drought tolerance might account for the survival of Laurus in continental Europe throughout the Quaternary whilst other Lauraceae became extinct. Climatic scenarios for the end of this century would favour an expansion of the species's range towards northern latitudes, while severely limiting southern populations due to increased water stress.     

Speciation in North American black basses,Micropterus (Actinopterygii: Centrarchidae)

Abstract.— The Pleistocene Epoch has been frequently cited as a period of intense speciation for a significant portion of temperate continental biotas. To critically assess the role of Pleistocene glaciations on the evolution of the freshwater fish clade Micropterus , we use a phylogenetic analysis of complete gene sequences from two mitochondrial genes (cytochrome b and ND2), and a fossil calibration of the molecular clock to estimate ages of speciation events and rates of diversification. The absence of substantial morphological and ecological divergence together with endemism of five of the eight species in North American tributaries of the Gulf of Mexico may be interpreted as the result of a recent Pleistocene origin for these species. Speciation dates in Micropterus range from 1.01 ± 0.32 to 11.17 ± 1.02 million years ago. Only one speciation event is dated to the Pleistocene, and rates of diversification are not significantly variable in Micropterus. The premise that the Pleistocene was an exceptional period of speciation in Micropterus is not supported. Instead, a Gulf Coast allopatric speciation model is proposed, and predicts periods of dynamic speciation driven by sea level fluctuations in the Late Miocene and Pliocene. The Pleistocene, however, was a period of significant intraspecific mitochondrial lineage diversification. The application of the Gulf Coast allopatric speciation model to the remaining aquatic fauna of the Gulf of Mexico coast in North America will rely on robust phylogenetic hypotheses and accurate age estimations of speciation events.     

Diversification in North American arid lands: Niche conservatism, divergence and expansion of habitat explain speciation in the genus Ephedra

A lineage of 12 arid land shrubby species in the gymnosperm genus Ephedra (Gnetales) from North America is used to evaluate the influence of climate on speciation. With a long evolutionary history, and a well documented fossil record this lineage is an ideal model for understanding the process of speciation under a niche conservatism scenario. Using seven DNA molecular markers, Bayesian inference is carried out to uncover sister species and to estimate time of divergence of the lineages. Ecological niche models are generated for four parapatric and sympatric sister species and two analyses of niche evolution are performed, one based on ecological niche models and another using raw data and multivariate analysis. As previous analyses suggest, the diversification of North America Ephedra species may be the result of a recent secondary radiation. Both parapatric and sympatric species diverged mostly in a scenario of climatic niche conservatism. However, we also found strong evidence for niche divergence for one of the sister species pairs (E. californica-E. trifurca). Moreover, the multivariate analysis found environmental differences for some variables between sister species. The estimated divergence time of three pairs of sister species distributed in southwestern North America (E. cutleri-E. aspera, E. californica-E. trifurca and E. torreyana-E. viridis) is inferred to have occurred in the Late Miocene to Pliocene and for the sister species pair E. antisyphilitica-E. coryi distributed in the southern United States and northeastern Mexico, it was inferred from the Pliocene to Pleistocene. The orogenetic and climatic changes documented for these regions related to expansion of arid lands, may have contributed to the diversification in North American Ephedra, rather than adaptations to new climatic conditions.     

Congruent phylogenetic and fossil signatures of mammalian diversification dynamics driven by Tertiary abiotic change

Computational methods for estimating diversification rates from extant species phylogenetic trees have become abundant in evolutionary research. However, little evidence exists about how their outcome compares to a complementary and direct source of information: the fossil record. Furthermore, there is virtually no direct test for the congruence of evolutionary rates based on these two sources. This task is only achievable in clades with both a well‐known fossil record and a complete phylogenetic tree. Here, we compare the evolutionary rates of ruminant mammals as estimated from their vast paleontological record—over 1200 species spanning 50 myr—and their living‐species phylogeny. Significantly, our results revealed that the ruminant's fossil record and phylogeny reflect congruent evolutionary processes. The concordance is especially strong for the last 25 myr, when living groups became a dominant part of ruminant diversity. We found empirical support for previous hypotheses based on simulations and neontological data: The pattern captured by the tree depends on how clade specific the processes are and which clades are involved. Also, we report fossil evidence for a postradiation speciation slowdown coupled with constant, moderate extinction in the Miocene. The recent deceleration in phylogenetic rates is connected to rapid extinction triggered by recent climatic fluctuations.