Distribution Of Extant Species Research Articles

Systematics and biogeography of the Old World fern genus Antrophyum.

Antrophyum is one of the largest genera of vittarioid ferns (Pteridaceae) and is most diverse in tropical Asia and the Pacific Islands, but also occurs in temperate Asia, Australia, tropical Africa and the Malagasy region. The only monographic study of Antrophyum was published more than a century ago and a modern assessment of its diversity is lacking. Here, we reconstructed a comprehensively sampled and robustly supported phylogeny for the genus based on four chloroplast markers using Bayesian inference, maximum likelihood and maximum parsimony analyses. We then explored the evolution of the genus from the perspectives of morphology, systematics and historical biogeography. We investigated nine critical morphological characters using a morphometric approach and reconstructed their evolution on the phylogeny. We describe four new species and provide new insight into species delimitation. We currently recognize 34 species for the genus and provide a key to identify them. The results of biogeographical analysis suggest that the distribution of extant species is largely shaped by both ancient and recent dispersal events.

The first fossilized comb-clawed beetle of the genus Asiomira Dubrovina, 1973 (Coleoptera: Tenebrionidae: Alleculinae) from Baltic Amber and notes on the distribution of extant species of the genus.

A new species of comb-clawed beetles of the genus Asiomira Dubrovina, 1973 (A. dubrovinae sp. n.) is described from the Eocene Baltic amber. This newly descovered fossil species displays typical generic characters and is the most similar to the extant Asiomira ophtalmica (Seidlitz, 1896). Both species share a similar shape of the pronotum and the flattened posterior angles of the pronotal disc. Asiomira dubrovinae sp. n. can be distinguished from A. ophtalmica by the smaller body size (4.8 mm in contrast to 68.12 mm), more serrate antennomeres, and finer and sparser pronotal punctation. Extant species of the genus are distributed in the arid landscapes of Central Asia with the highest diversity occurring in Tajikistan. Therefore the discovery of a new fossil species from Eocene Baltic amber suggests that Asiomira could have a wider range, and the modern distribution of this group is the result of a later secondary expansion of the ancestral representatives that survived in mid-mountain areas with arboreal and shrub vegetation. Relevant corrections to the distribution of extant species, Asiomira ophtalmica (Seidlitz, 1896) and Asiomira firjusana (Dubrovina, 1973), are given.

Phylogenetics and historical biogeography of Solanum section Brevantherum (Solanaceae)

Patterns of diversification in Neotropical plants have been studied intensively over the past decades. Most studies have focused on groups that migrated to and radiated into the Neotropics, however, with little focus on understanding diversification patterns in indigenous Neotropical groups. This study focuses on Solanum section Brevantherum Seithe (Solanaceae), a group of Neotropical nightshade shrubs or treelets defined mostly by terminal inflorescences with long peduncles, plurifoliate sympodial units and porrect-stellate, dendritic-echinoid, or lepidote trichomes. We generated sequences from two nuclear (ITS, waxy) and one plastid marker (trnT-F) to infer phylogenetic relationships under Bayesian and Maximum likelihood approaches. We reconstructed a time-calibrated tree to estimate both the ages of main splits and the ancestral ranges of the lineages. Finally, we carried out a biogeographic stochastic mapping (BSM) analysis to determine the main processes driving current distributions of the group. Results show the non-monophyly of the section as previously recognized and the homoplasy of morphological characters traditionally used to circumscribe it. Two main clades that encompass most species formerly recognized in section Brevantherum are recovered and named as the Erianthum and Abutiloides clades. Divergence time estimates suggest that the Erianthum and Abutiloides clades split around 5.7 Mya in the upper Miocene. Two main dispersal events from the Atlantic rainforest are supported in the Erianthum clade: one dispersal to Mesoamerica and a second dispersal to the Northern Andes. Within the Abutiloides clade, cladogenetic events were restricted to the Andean region. Our BSM analysis suggests within-area speciation and range expansion as the main processes shaping the extant distribution of species of both clades. As no putative morphological synapomorphies can yet be assigned to what could correspond to a new circumscription of Solanum section Brevantherum (with the exclusion of Solanum bullatum Vell. and inclusion of S. inelegans Rusby and four species described since the group last revision) we discourage the continued use of what would be an ambiguous sectional nomenclature.

Hydrodynamic Simulations of the Performance Landscape for Suction-Feeding Fishes Reveal Multiple Peaks for Different Prey Types.

The complex interplay between form and function forms the basis for generating and maintaining organismal diversity. Fishes that rely on suction-feeding for prey capture exhibit remarkable phenotypic and trophic diversity. Yet the relationships between fish phenotypes and feeding performance on different prey types are unclear, partly because the morphological, biomechanical, and hydrodynamic mechanisms that underlie suction-feeding are complex. Here we demonstrate a general framework to investigate the mapping of multiple phenotypic traits to performance by mapping kinematic variables to suction-feeding capacity. Using a mechanistic model of suction-feeding that is based on core physical principles, we predict prey capture performance across a broad range of phenotypic trait values, for three general prey types: mollusk-like prey, copepod-like prey, and fish-like prey. Mollusk-like prey attach to surfaces, copepod-like prey attempt to escape upon detecting the hydrodynamic disturbance produced by the predator, and fish-like prey attempt to escape when the predator comes within a threshold distance. This approach allowed us to evaluate suction-feeding performance for any combination of six key kinematic traits, irrespective of whether these trait combinations were observed in an extant species, and to generate a multivariate mapping of phenotype to performance. We used gradient ascent methods to explore the complex topography of the performance landscape for each prey type, and found evidence for multiple peaks. Characterization of phenotypes associated with performance peaks indicates that the optimal kinematic parameter range for suction-feeding on different prey types are narrow and distinct from each other, suggesting different functional constraints for the three prey types. These performance landscapes can be used to generate hypotheses regarding the distribution of extant species in trait space and their evolutionary trajectories toward adaptive peaks on macroevolutionary fitness landscapes.

Native and Invasive Small Mammals in Urban Habitats along the Commercial Axis Connecting Benin and Niger, West Africa

Based on compiled small mammal trapping data collected over 12 years from Benin and Niger (3701 individual records from 66 sampling sites), located in mainland Africa, we here describe the small mammal community assemblage in urban habitats along the commercial axis connecting the two countries, from the seaport of Cotonou to the Sahelian hinterland, with a particular focus on invasive species. In doing so, we document extant species distributions, which highlight the risks of continuing the range expansion of three synanthropic invasive rodent species, namely black rats (Rattus rattus), brown rats (R. norvegicus), and house mice (Mus musculus). Using various diversity estimates and community ecology approaches, we detect a latitudinal gradient of species richness that significantly decreased Northward. We show that shrews (Crocidura) represent a very important component of micro-mammal fauna in West African towns and villages, especially at lower latitudes. We also demonstrate that invasive and native synanthropic rodents do not distribute randomly in West Africa, which suggests that invasive species dynamics and history differ markedly, and that they involve gradual, as well as human-mediated, long distance dispersal. Patterns of segregation are also observed between native Mastomys natalensis and invasive rats R. rattus and R. norvegicus, suggesting potential native-to-invasive species turn over. Consequences of such processes, especially in terms of public health, are discussed.

Impact of Habitat Loss and Mining on the Distribution of Endemic Species of Amphibians and Reptiles in Mexico

Mexico holds an exceptional diversity and endemicity of amphibian and reptile species, but several factors pose a threat to their conservation. Here, we produced ecological niche models for 179 Mexican endemic amphibian and reptile species and examined the impact of habitat loss and mining activities on their projected potential distributions, resulting in their extant distributions. We compared extant species distributions to the area required to conserve a minimum proportion of the species distribution. The combined impact of habitat loss and mining on extant species distribution was significantly higher than the impact of habitat loss alone. Only 40 species lost <30% of their distribution, while 83 species lost between 30–50%, 54 species lost between 50–80%, and 2 species lost more than 80% of their distribution. Furthermore, the size and configuration of the area required to conserve 20% of the extant species distributions changed considerably by increasing the number of fragments, with a potential increase in local population extirpations. Our study is the first to address the combined impact of habitat loss and mining on a highly vulnerable rich endemic species group, leading to a decrease in their potential distribution and a potential increase in the extinction risk of species.

Molecular Phylogeny and Historical Biogeography of the Butterfly Tribe Aeromachini Tutt (Lepidoptera: Hesperiidae) from China.

The butterfly tribe Aeromachini Tutt, 1906 is a large group of skippers. In this study, a total of 10 genera and 45 species of putative members of this tribe, which represent most of the generic diversity and nearly all the species diversity of the group in China, were sequenced for two mitochondrial genes and three nuclear genes (2093 bp). The combined dataset was analyzed with maximum likelihood inference using IQtree. We found strong support for monophyly of Aeromachini from China and support for the most recent accepted species in the tribe. Two paraphyletic genera within Aeromachini are presented and discussed. The divergence time estimates with BEAST and ancestral-area reconstructions with RASP provide a detailed description about the historical biogeography of the Aeromachini from China. The tribe very likely originated from the Hengduan Mountains in the late Ecocene and expanded to the Himalaya Mountains and Central China Regions. A dispersal-vicariance analysis suggests that dispersal events have played essential roles in the distribution of extant species, and geological and climatic changes have been important factors driving current distribution patterns.

Quaternary refugia are associated with higher speciation rates in mammalian faunas of the Western Palaearctic

Quaternary climate changes have contributed to shape the biogeographic distribution of extant species. The combination of climatic niche conservatism and glacial‐interglacial cycles forced many species to retract their range limits for surviving under the advance of Pleistocene ice‐sheets. Refugia offered geographical opportunities for species to retreat, persist and, later on, begin recolonization processes under favourable environmental conditions. Here we explore the hypothesis that refugia have been not only crucial for the survival of multiple species but also acted as speciation centres for Western Palaearctic mammals. We define ‘recurrent massive refugia’ as those geographical regions that have historically accumulated the highest levels of co‐occurring species for several Quaternary cycles. Our assemblage‐level analyses identify the existence of refugia within the Iberian Peninsula and the Atlantic French margin that were recurrently selected by most mammals. The topographic heterogeneity, climatic stability and microhabitat availability of these refugial areas may have offered suitable habitat conditions for multiple species during different climatic events over time. Using a Bayesian analysis of macroevolutionary mixtures we detected that the higher level of divergence and accumulative evolutionary changes in mammals of the Western Palaearctic are found in refugia. The continuous retractions and expansions of species’ ranges during the Pleistocene promoted temporal changes in the composition and richness of communities in this biogeographic region. The reorganization of ecological composition driven by cyclical climatic events may have favoured the emergence of biotic interactions and ecological responses conducive to novel selective pressures. Our findings suggest, first, that multiple climatic changes in the form of glacial‐interglacial transitions during the Quaternary have left a detectable imprint on the observed geographical patterns of species richness in mammalian faunas of the Western Palaearctic, and second, highlight the importance of refugia for the preservation of species (‘museums’) and as centers of speciation and endemism (‘cradles’) as well.

Preliminary molecular phylogeny and biogeography of the monobasic subfamily Calinaginae (Lepidoptera, Nymphalidae)

Calinaga (Moore 1857) is a rare and enigmatic Asian butterfly genus whose phylogenetic placement within Nymphalidae has only recently been established. The evolutionary history of Calinaga species however remains unknown. Here we explore the phylogeography of Calinaga using 1310 bp of sequence data from two molecular (mtDNA barcode and ribosomal protein S5 nuclear gene) and two morphological traits (genitalia and wing pattern). Within the proposed phylogenetic framework, we estimate the ages of divergence within the genus and reconstruct their historical biogeography. We found strong support for monophyly of Calinaga and support for the most recent accepted species in the genus. Our results indicate that the common ancestor of Calinaga first split in the Eocene (~43 million years ago) in southern China, probably as a consequence of geological and environmental impacts of the collision of the Indian and Asian subcontinents. In the Oligocene/Miocene, the extrusion of Indochina from the continent caused further dramatic orogenetic changes that promoted isolation and speciation events within the genus while Pleistocene climatic changes also influenced the distribution and further speciation. A dispersal–vicariance analysis suggests that vicariance events have played a far more important role than dispersal in the distribution of extant species.

Dipterocarpaceous macrofossils from Churia Group of Arjun Khola area, western Nepal and their phytogeographical and palaeoclimatical implications

Investigation of plant megafossils collected from Churia Group of western Nepal revealed the presence of fossil wood, leaves and a fruit of a phytogeographically important genus, Dipterocarpus Gaertn. f. of the family Dipterocarpaceae. These have been described under the form species, Dipterocarpoxylon siwalicus Prakash, Dipterocarpus suraikholaensis Prasad and Pandey, and three new species namely Dipterocarpus nepalensis n. sp., D. miocenicus and D. churiensis. The analysis of present day distribution of extant species of Dipterocarpus comparable to the fossil remains indicates that they do not grow in the sub–himalayan zone of India and Nepal; instead they are presently distributed in the evergreen forests of South–east Asian region (Myanmar, Malaya, Java, Borneo, etc.). This suggests that after rise of Himalaya, drier conditions prevailed so that such species could no longer survive there. Based on the present and past distribution of the comparable extant species of Dipterocarpus, the phytogeography as well as migration of this genus has been discussed. The finding of dipterocarps in the Siwalik sediments of Himalayan foot hills of Nepal suggests that they have migrated from the South–east Asian region during early Miocene and later on became locally extinct due to prevailing of unfavourable condition. An attempt has also been made to categorize the already known species of Dipterocarpoxylon having almost similar anatomical features.

From the Namib around the world: biogeography of the Inuleae–Plucheinae (Asteraceae)

AbstractAimWe investigated the historical biogeography of the Inuleae–Plucheinae (Asteraceae), a group of arid‐adapted plants with partly unresolved generic circumscriptions, in order to understand its origin and spatiotemporal evolutionary history in relation to the Cenozoic climate shifts.LocationGlobal, with highest species diversity in the Southern Hemisphere.MethodsThe spatiotemporal biogeography of the Plucheinae was estimated by both a discrete method using a set of general distribution areas, and a relaxed random walk based on extant species distributions. The topology was time calibrated using a combination of secondary node ages and secondary derived rates for included loci.ResultsOur results indicate the median age of the Plucheinae to be approximately 15.4 Ma. The biogeographical analyses infer an ancestral origin in southern Africa, with the relaxed random walk analysis narrowing the uncertainty down to an area reaching from coastal Namibia to the western Kalahari. Africa was colonized in a (south)western–(north)eastern direction following the spread of arid habitats. Ancestral representatives of the Plucheinae colonized South America on at least three separate occasions (13.0–4.0, 4.3–3.1 and 4.1–3.7 Ma), with one subsequent spread to North America. Australia was colonized three times between 3.6 and 0.4 Ma. Madagascar and the Mascarenes were colonized at least seven times.Main conclusionsThe origin of the Plucheinae is estimated to the Namib region, with early speciations and radiations concurring with the timing of aridification of southern Africa, following the increase in strength of the Antarctic Circumpolar Current and subsequent formation of the Benguela Upwelling at c. 11.8 Ma. The current biogeographical distribution of the Plucheinae is best explained by several Neogene long‐distance dispersal events from tropical Africa.

Palaeoecological and biostratigraphical implications of the microvertebrates of Qesem Cave in Israel

Microvertebrates are generally well suited for drawing inferences on past environmental conditions because they are closely bound to the areas in which they lived. In this paper, we discuss palaeoecological implications of two microvertebrate concentrations in the Middle Pleistocene site Qesem Cave in Israel. The ecological preferences of the nearest living relatives of the microvertebrate taxa recorded in Concentration 1 (squares L–N/13–15) and 2 (squares G-H/16–17) at Qesem Cave allow us to infer a mosaic of open palaeoenvironment with sparse vegetation, shrubland, Mediterranean Forest, rocky areas and riverbanks. Additionally, we infer palaeoclimate from the bioclimatic distribution of extant species using the Coexistence Approach. To our knowledge, this is the first time the approach has been applied to microfaunal assemblages. These data suggest cooler and slightly drier winters and somewhat lower seasonality than at present around Qesem Cave; the differences are more pronounced for the time covered by Concentration 2 than Concentration 1.Among microvertebrates, micromammals are most suitable for biostratigraphic purposes. With the exception of Rattus cf. haasi and the Myomimus judaicus/setzeri group, the small mammal fauna of Qesem Cave comprises only taxa that live today in the Levant. R. haasi and M. judaicus have been found in Israel in the Early and Middle Pleistocene, and their latest known record was from the Acheulian site of Oumm Qatafa. Their presence in Qesem Cave extends the previously known stratigraphic range of these species. The absence of R. haasi in Mousterian sites is thus consistent with the pre-Mousterian age of Qesem Cave. Morphometric data on molars of Guenther's Vole show that the lineage segment preserved in Concentration 2 is more primitive than in Concentration 1, indicating that the former concentration is older. The evolutionary level of the sample from Qesem Concentration 1 is similar to Tabun D (boundary of Acheulo-Yabrudian Cultural Complex and Mousterian), and that from Qesem Concentration 2 similar to Tabun Eb (Acheulo-Yabrudian).

Testudinoidea Fitzinger (Testudines: Cryptodira) de la Formación Toropí/Yupoí (ca. 58-28 ka) en la Provincia de Corrientes, Argentina: taxonomía y aspectos paleoambientales

Fil: Zacarias, Gerardo Gabriel. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; Argentina

Integrating fossils, phylogenies, and niche models into biogeography to reveal ancient evolutionary history: the case of Hypericum (hypericaceae).

In disciplines such as macroevolution that are not amenable to experimentation, scientists usually rely on current observations to test hypotheses about historical events, assuming that “the present is the key to the past.” Biogeographers, for example, used this assumption to reconstruct ancestral ranges from the distribution of extant species. Yet, under scenarios of high extinction rates, the biodiversity we observe today might not be representative of the historical diversity and this could result in incorrect biogeographic reconstructions. Here, we introduce a new approach to incorporate into biogeographic inference the temporal, spatial, and environmental information provided by the fossil record, as a direct evidence of the extinct biodiversity fraction. First, inferences of ancestral ranges for those nodes in the phylogeny calibrated with the fossil record are constrained to include the geographic distribution of the fossil. Second, we use fossil distribution and past climate data to reconstruct the climatic preferences and potential distribution of ancestral lineages over time, and use this information to build a biogeographic model that takes into account “ecological connectivity” through time. To show the power of this approach, we reconstruct the biogeographic history of the large angiosperm genus Hypericum, which has a fossil record extending back to the Early Cenozoic. Unlike previous reconstructions based on extant species distributions, our results reveal that Hypericum stem lineages were already distributed in the Holarctic before diversification of its crown-group, and that the geographic distribution of the genus has been relatively stable throughout the climatic oscillations of the Cenozoic. Geographical movement was mediated by the existence of climatic corridors, like Beringia, whereas the equatorial tropical belt acted as a climatic barrier, preventing Hypericum lineages to reach the southern temperate regions. Our study shows that an integrative approach to historical biogeography—that combines sources of evidence as diverse as paleontology, ecology, and phylogenetics—could help us obtain more accurate reconstructions of ancient evolutionary history. It also reveals the confounding effect different rates of extinction across regions have in biogeography, sometimes leading to ancestral areas being erroneously inferred as recent colonization events.

Biogeographic Analysis Reveals Ancient Continental Vicariance and Recent Oceanic Dispersal in Amphibians

Amphibia comprises over 7000 extant species distributed in almost every ecosystem on every continent except Antarctica. Most species also show high specificity for particular habitats, biomes, or climatic niches, seemingly rendering long-distance dispersal unlikely. Indeed, many lineages still seem to show the signature of their Pangaean origin, approximately 300 Ma later. To date, no study has attempted a large-scale historical-biogeographic analysis of the group to understand the distribution of extant lineages. Here, I use an updated chronogram containing 3309 species (∼ 45% of extant diversity) to reconstruct their movement between 12 global ecoregions. I find that Pangaean origin and subsequent Laurasian and Gondwanan fragmentation explain a large proportion of patterns in the distribution of extant species. However, dispersal during the Cenozoic, likely across land bridges or short distances across oceans, has also exerted a strong influence. Finally, there are at least three strongly supported instances of long-distance oceanic dispersal between former Gondwanan landmasses during the Cenozoic. Extinction from intervening areas seems to be a strong factor in shaping present-day distributions. Dispersal and extinction from and between ecoregions are apparently tied to the evolution of extraordinarily adaptive expansion-oriented phenotypes that allow lineages to easily colonize new areas and diversify, or conversely, to extremely specialized phenotypes or heavily relictual climatic niches that result in strong geographic localization and limited diversification.

Biogeographic history of two Eurasian Cenozoic charophyte lineages

The long-term biogeographic history of charophytes is a highly relevant, although little-studied topic to understand the distribution of extant species. Two contrasting biogeographic histories of Eurasian charophyte lineages are documented and the reasons for such wide distributions are explored. Nitellopsis (Tectochara) merianii–Nitellopsis obtusa is a charophyte lineage ranging from the latest Eocene to the present and displaying Eurasian distribution since the Late Oligocene. Lychnothamnus stockmansii–Lychnothamnus major lineage is defined here as an Eurasian charophyte lineage ranging from the Late Eocene to the Early Oligocene. Both lineages are well documented in the fossil record owing to their applications in stratigraphic dating. The historical biogeography of these lineages displays two opposite patterns. The lineage L. stockmansii–L. major displays an Eurasian distribution from its first occurrence in the Late Eocene, whilst the lineage N. (T.) merianii–N. obtusa underwent a long period of European provincialism ranging from the Late Eocene to the end of the Early Oligocene (an interval of 10 million years, Ma), to begin later, during the Late Oligocene and Miocene, an eastwards expansion until reaching its present Eurasian distribution. These two different biogeographic patterns appear to be related to the contrasting mechanisms of dispersal in monoecious vs dioecious charophytes, well known in extant Chara, and allow us to identify the time needed by characeans to reach supra-continental distributions.

Inferring geographic range evolution of a pantropical tribe in the coffee family (Lasiantheae, Rubiaceae) in the face of topological uncertainty

In this study we explore what historical biogeographic events are responsible for the wide and disjunct distribution of extant species in Lasiantheae, a pantropical group of trees and shrubs in the coffee family. Three of the genera in the group, Lasianthus, Saldinia, and Trichostachys, are found to be monophyletic, while there are indications that the fourth, Ronabea, is paraphyletic. We also address how the uncertainty in topology and divergence times affects the level of confidence in the biogeographic reconstruction. A data set consisting of chloroplast and nuclear ribosomal DNA data was analyzed using a Bayesian relaxed molecular clock approach to estimate phylogenetic relationships and divergence times, and the dispersal–extinction–cladogenesis (DEC) method to reconstruct geographic range evolution. Our results show that the Lasiantheae stem lineage originated in the neotropics, and the group expanded its range to the palaeotropics during the Eocene, either by continental migration through the boreotropics or by transatlantic long-distance dispersal. Two cases of Oligocene/Miocene over water-dispersal were also inferred, once from the paleotropics to the neotropics within Lasianthus, and once to Madagascar, concurrent with the origin of Saldinia. A lot of the diversification within Lasianthus took place during the Miocene and may have been influenced by climatic factors such as a period of markedly warm and moist climate in Asia and the aridification of the interior of the African continent. When biogeographic reconstructions were averaged over a random sample of 1000 dated phylogenies, the confidence in the biogeographic reconstruction decreased for most nodes, compared to when a single topology was used. A good understanding of phylogenetic relationships is necessary to understand the biogeographic history of a group, bit since the phylogeny is rarely completely known it is important to include phylogenetic uncertainty in biogeographic analysis. For nodes where the resolution is uncertain, the use of a single “best” topology as a basis for biogeographic analysis will result in inflated confidence in a biogeographic reconstruction which may be just one of several possible reconstructions.

Evolutionary History of Lagomorphs in Response to Global Environmental Change

Although species within Lagomorpha are derived from a common ancestor, the distribution range and body size of its two extant groups, ochotonids and leporids, are quite differentiated. It is unclear what has driven their disparate evolutionary history. In this study, we compile and update all fossil records of Lagomorpha for the first time, to trace the evolutionary processes and infer their evolutionary history using mitochondrial genes, body length and distribution of extant species. We also compare the forage selection of extant species, which offers an insight into their future prospects. The earliest lagomorphs originated in Asia and later diversified in different continents. Within ochotonids, more than 20 genera occupied the period from the early Miocene to middle Miocene, whereas most of them became extinct during the transition from the Miocene to Pliocene. The peak diversity of the leporids occurred during the Miocene to Pliocene transition, while their diversity dramatically decreased in the late Quaternary. Mantel tests identified a positive correlation between body length and phylogenetic distance of lagomorphs. The body length of extant ochotonids shows a normal distribution, while the body length of extant leporids displays a non-normal pattern. We also find that the forage selection of extant pikas features a strong preference for C3 plants, while for the diet of leporids, more than 16% of plant species are identified as C4 (31% species are from Poaceae). The ability of several leporid species to consume C4 plants is likely to result in their size increase and range expansion, most notably in Lepus. Expansion of C4 plants in the late Miocene, the so-called ‘nature’s green revolution’, induced by global environmental change, is suggested to be one of the major ‘ecological opportunities’, which probably drove large-scale extinction and range contraction of ochotonids, but inversely promoted diversification and range expansion of leporids.

Phylogeny and biogeography of the Laurasian genus Agonum Bonelli (Coleoptera, Carabidae, Platynini)

The World fauna of Agonum Bonelli, 1810 was analyzed by cladistic parsimony implementing Nixon's ratchet, based on 135 terminals representing 131 species, and 138 unit-coded characters, including 98 external morphological characters, 21 characters of the female reproductive tract and ovipositor, and 19 male genitalic characters. The cladogram was outgroup-rooted to the African Agonidium Jeannel, 1948. Phylogenetic data were summarized via strict consensus; this consensus was used as the basis for cladistic classification. A single preferred cladogram was chosen from among 4576 unambiguously optimized, equally parsimonious cladograms using Goloboffs fit value as an optimality criterion, and converted to a taxon-area cladogram for biogeographic analysis. Coxal and femoral setation has generally increased during phylogenesis, and served to define natural groups. The configuration of the female bursa copulatrix helped define the Agonum ingroup. Spermathecal duct length has increased dramatically during diversification of Agonum, though reversal to a short, broad duct has also occurred. A balanced cladistic classification based on relationships maintained in the strict consensus cladogram recognized four subgenera: Platynomicrus Casey, 1920 (2 spp.), Europhilus Chaudoir, 1859 (28 spp.), Agonum (29 spp.), and Agonothorax Motschulsky, 1850 (72 spp.). Nomenclatural changes necessitated by the cladistic analysis include: 1, Megalonychus Chaudoir, 1843 = Agonum Bonelli, 1810; 2, Agonops Bousquet, 2002 = Agonum Bonelli, 1810; 3, 12 species previously combined with Megalonychus are NEWLY COMBINED with Agonidium, whereas the remaining 32 species previously combined with Megalonychus are provisionally assigned to Agonidium pending future study. Fossil locality data were used to determine Pliocene and Pleistocene distributional limits, and to establish minimum ages for extant taxa. Estimates of species duration for three species preserved in the Beaufort Formation of Arctic Canada range from 3–4,000,000 yr. Pliocene and Pleistocene fossil localities in eastern North America and Greenland augmented extant species distributions analyzed biogeographically. Dispersal-vicariance biogeographic analysis (DIVA), which optimized area relationships among major areas of endemism in the northern hemisphere using the taxon-area cladogram, indicated that Agonum diversification began in Eocene time when Europe and Eastern North America were connected by North Atlantic Land Bridges. Eocene origin of Agonum is consistent with a Paleocene-constrained biotic connection to the African outgroup Agonidium. Subsequently, Beringian exchange was associated with Agonum diversification through Late Miocene and Pliocene. Dispersal across Pleistocene-aged Beringia is associated strictly with extant Holarctic and circumpolar species. Plesiomorphically, Agonum beetles were marsh dwellers. Subsequent ecological specialization has involved use umbrotrophic bogs, gravel and cobble streambank habitats, shores of saline lakes and seashores, and moist forest floors. Speciation has followed both an allopatric vicariant mode, and peripatric isolation of peripheral populations. Both Mayr's centripetal speciation and Brown's centrifugal speciation models were supported by geographic relationships of various sister species, indicating that environmental factors have greatly influenced speciation mode, especially of peripheral isolates.

Boreotropical migration explains hybridization between geographically distant lineages in the pantropical clade Sideroxyleae (Sapotaceae)

To determine whether the fragmented pantropical distribution of present day Sideroxyleae primarily is the result of long-distance dispersals or represents the remnants of a once continuous distribution in the northern hemisphere, the boreotropical flora, we used phylogenetic analyses of chloroplast and nuclear ribosomal DNA data, Bayesian molecular dating, and Bayesian estimation of ancestral areas. Incongruence between the two data sets was examined with a nuclear low copy gene phylogeny to discover any occurrences of reticulate evolution. The Pacific clade Nesoluma was shown to have two distinct copies of the nuclear low copy gene AAT, one from an African and one from an American ancestral lineage, indicating that it is of allopolyploid origin. We conclude that Sideroxyleae, including the ancestral lineages of Nesoluma, were part of the boreotropical flora and entered the New World via the north Atlantic land bridge. We also suggest that the distribution of extant species resulted from the cooling climate at the end of the Eocene. Sideroxylon oxyacanthum is shown not to belong in the group, but in Chrysophylloideae. A classification reflecting phylogenetic relationships, as well as new combinations for the species in Nesoluma under Sideroxylon, is presented.