Body mass evolution and diversification within horses (family Equidae)

Horses (family Equidae) are a classic example of adaptive radiation, exhibiting a nearly 60‐fold increase in maximum body mass and a peak taxonomic diversity of nearly 100 species across four continents. Such patterns are commonly attributed to niche competition, in which increased taxonomic diversity drives increased size disparity. However, neutral processes, such as macroevolutionary ‘diffusion’, can produce similar increases in disparity without increased diversity. Using a comprehensive database of Equidae species size estimates and a common mathematical framework, we measure the contributions of diversity‐driven and diffusion‐driven mechanisms for increased disparity during the Equidae radiation. We find that more than 90% of changes in size disparity are attributable to diffusion alone. These results clarify the role of species competition in body size evolution, indicate that morphological disparity and species diversity may be only weakly coupled in general, and demonstrate that large species may evolve from neutral macroevolutionary diffusion processes alone.     

Perissodactyl diversities and responses to climate changes as reflected by dental homogeneity during the Cenozoic in Asia

Cenozoic mammal evolution and faunal turnover are considered to have been influenced and triggered by global climate change. Teeth of large terrestrial ungulates are reliable proxies to trace long‐term climatic changes due to their morphological and physicochemical properties; however, the role of premolar molarization in ungulate evolution and related climatic change has rarely been investigated. Recently, three patterns of premolar molarization among perissodactyls have been recognized: endoprotocrista‐derived hypocone (type I); paraconule–protocone separation (type II); and metaconule‐derived pseudohypocone (type III). These three patterns of premolar molarization play an important role in perissodactyl diversity coupled with global climate change during the Cenozoic in Asia. Those groups with a relatively higher degree of premolar molarization, initiated by the formation of the hypocone, survived into Neogene, whereas those with a lesser degree of molarization, initiated by the deformation of existing ridges and cusps, went extinct by the end of the Oligocene. In addition, the hypothesis of the “Ulan Gochu Decline” is proposed here to designate the most conspicuous decrease of perissodactyl diversity that occurred in the latest middle Eocene rather than at the Eocene–Oligocene transition in Asia, as conventionally thought; this event was likely comparable to the contemporaneous post‐Uintan decline of the North American land fauna.     

British mammals in the Tertiary period

British Tertiary mammals are best represented in the Eocene and earliest Oligocene epochs. Additional occurrences are from the Miocene and Late Pliocene. The Eocene is marked by the occurrence of various extinct orders as well as the appearances of some of the earliest and must primitive artiodactyls and perissodactyls. The appearances in the Early Eocene and Early Oligocene represent major dispersal events, reflecting penecontemporaneous palaeogeographic changes. In the intervening timespan Britain was part of an European island, sharing its endemic terrestrial fauna. From the late Middle Eocene to earliest Oligocene, the British record is detailed enough to trace successive changes in the patterns of diversity and faunal turnover, which may relate to changing climate as well as to the dispersal events. It has been shown that changes in patterns of ecological diversity through the Eocene and earliest Oligocene match vegetational changes judged from plant fossils. They suggest a gradual transition from closed forest in the Early Eocene to a more open environment with reedmarsh and wooded patches by the end of the epoch.     

Mass turnover and recovery dynamics of a diverse Australian continental radiation

Trends in global and local climate history have been linked to observed macroevolutionary patterns across a variety of organisms. These climatic pressures may unilaterally or asymmetrically influence the evolutionary trajectory of clades. To test and compare signatures of changing global (Eocene‐Oligocene boundary cooling) and continental (Miocene aridification) environments on a continental fauna, we investigated the macroevolutionary dynamics of one of Australia's most diverse endemic radiations, pygopodoid geckos. We generated a time‐calibrated phylogeny (>90% taxon coverage) to test whether (i) asymmetrical pygopodoid tree shape may be the result of mass turnover deep in the group's history, and (ii) how Miocene aridification shaped trends in biome assemblages. We find evidence of mass turnover in pygopodoids following the isolation of the Australian continental plate ～30 million years ago, and in contrast, gradual aridification is linked to elevated speciation rates in the young arid zone. Surprisingly, our results suggest that invasion of arid habitats was not an evolutionary end point. Instead, arid Australia has acted as a source for diversity, with repeated outward dispersals having facilitated diversification of this group. This pattern contrasts trends in richness and distribution of other Australian vertebrates, illustrating the profound effects historical biome changes have on macroevolutionary patterns.     

Why are There Fewer Marsupials than Placentals? On the Relevance of Geography and Physiology to Evolutionary Patterns of Mammalian Diversity and Disparity

Placental mammals occupy a larger morphospace and are taxonomically more diverse than marsupials by an order of magnitude, as shown by quantitative and phylogenetic studies of several character complexes and clades. Many have suggested that life history acts as a constraint on the evolution of marsupial morphology. However, the frequent circumvention of constraints suggests that the pattern of morphospace occupation in marsupials is more a reflection of lack of ecological opportunity than one of biases in the production of variants during development. Features of marsupial physiology are a potential source of biases in the evolution of the group; these could be coupled with past macroevolutionary patterns that followed conditions imposed by global temperature changes. This is evident at the K/Pg boundary and at the Eocene/Oligocene boundary. The geographic pattern of taxonomic and morphological diversity in placental clades mirrors that of extant placentals as a whole versus marsupials: placentals of northern origin are more diverse those of southern one and include the clades that are outliers in taxonomic (rodents and bats) and ecomorphological (whales and bats) richness.     

gen3sis: A general engine for eco-evolutionary simulations of the processes that shape Earth’s biodiversity

Understanding the origins of biodiversity has been an aspiration since the days of early naturalists. The immense complexity of ecological, evolutionary, and spatial processes, however, has made this goal elusive to this day. Computer models serve progress in many scientific fields, but in the fields of macroecology and macroevolution, eco-evolutionary models are comparatively less developed. We present a general, spatially explicit, eco-evolutionary engine with a modular implementation that enables the modeling of multiple macroecological and macroevolutionary processes and feedbacks across representative spatiotemporally dynamic landscapes. Modeled processes can include species’ abiotic tolerances, biotic interactions, dispersal, speciation, and evolution of ecological traits. Commonly observed biodiversity patterns, such as α, β, and γ diversity, species ranges, ecological traits, and phylogenies, emerge as simulations proceed. As an illustration, we examine alternative hypotheses expected to have shaped the latitudinal diversity gradient (LDG) during the Earth’s Cenozoic era. Our exploratory simulations simultaneously produce multiple realistic biodiversity patterns, such as the LDG, current species richness, and range size frequencies, as well as phylogenetic metrics. The model engine is open source and available as an R package, enabling future exploration of various landscapes and biological processes, while outputs can be linked with a variety of empirical biodiversity patterns. This work represents a key toward a numeric, interdisciplinary, and mechanistic understanding of the physical and biological processes that shape Earth’s biodiversity.

This study describes a novel mechanistic engine that predicts a realistic global latitudinal diversity gradient, species richness distribution and phylogenies. This approach is a step towards the interdisciplinary numeric understanding of the physical and biological processes that have shaped Earth’s biodiversity.     

Effects of allometry,productivity and lifestyle on rates and limits of body size evolution

Body size affects nearly all aspects of organismal biology, so it is important to understand the constraints and dynamics of body size evolution. Despite empirical work on the macroevolution and macroecology of minimum and maximum size, there is little general quantitative theory on rates and limits of body size evolution. We present a general theory that integrates individual productivity, the lifestyle component of the slow–fast life-history continuum, and the allometric scaling of generation time to predict a clade''s evolutionary rate and asymptotic maximum body size, and the shape of macroevolutionary trajectories during diversifying phases of size evolution. We evaluate this theory using data on the evolution of clade maximum body sizes in mammals during the Cenozoic. As predicted, clade evolutionary rates and asymptotic maximum sizes are larger in more productive clades (e.g. baleen whales), which represent the fast end of the slow–fast lifestyle continuum, and smaller in less productive clades (e.g. primates). The allometric scaling exponent for generation time fundamentally alters the shape of evolutionary trajectories, so allometric effects should be accounted for in models of phenotypic evolution and interpretations of macroevolutionary body size patterns. This work highlights the intimate interplay between the macroecological and macroevolutionary dynamics underlying the generation and maintenance of morphological diversity.     

THE MICRO AND MACRO IN BODY SIZE EVOLUTION

The diversity of body sizes of organisms has traditionally been explained in terms of microevolutionary processes: natural selection owing to differential fitness of individual organisms, or to macroevolutionary processes: species selection owing to the differential proliferation of phylogenetic lineages. Data for terrestrial mammals and birds indicate that even on a logarithmic scale frequency distributions of body mass among species are significantly skewed towards larger sizes. We used simulation models to evaluate the extent to which macro- and microevolutionary processes are sufficient to explain these distributions. Simulations of a purely cladogenetic process with no bias in extinction or speciation rates for different body sizes did not produce skewed log body mass distributions. Simulations that included size-biased extinction rates, especially those that incorporated anagenetic size change within species between speciation and extinction events, regularly produced skewed distributions. We conclude that although cladogenetic processes probably play a significant role in body size evolution, there must also be a significant anagenetic component. The regular variation in the form of mammalian body size distributions among different-sized islands and continents suggests that environmental conditions, operating through both macro- and microevolutionary processes, determine to a large extent the diversification of body sizes within faunas. Macroevolution is not decoupled from microevolution.     

Paleogene Land Mammal Faunas of South America; a Response to Global Climatic Changes and Indigenous Floral Diversity

An appraisal of Paleogene floral and land mammal faunal dynamics in South America suggests that both biotic elements responded at rate and extent generally comparable to that portrayed by the global climate pattern of the interval. A major difference in the South American record is the initial as well as subsequent much greater diversity of both Neotropical and Austral floras relative to North American counterparts. Conversely, the concurrent mammal faunas in South America did not match, much less exceed, the diversity seen to the north. It appears unlikely that this difference is solely due to the virtual absence of immigrants subsequent to the initial dispersal of mammals to South America, and cannot be explained solely by the different collecting histories of the two regions. Possible roles played by non-mammalian vertebrates in niche exploitation remain to be explored. The Paleogene floras of Patagonia and Chile show a climatic pattern that approximates that of North America, with an increase in both Mean Annual Temperature (MAT) and Mean Annual Precipitation (MAP) from the Paleocene into the Early Eocene Climatic Optimum (EECO), although the Paleocene-Eocene Thermal Maximum (PETM) is not recognized in the available data set. Post-EECO temperatures declined in both regions, but more so in the north than the south, which also retained a higher rate of precipitation. The South American Paleogene mammal faunas developed gradual, but distinct, changes in composition and diversity as the EECO was approached, but actually declined somewhat during its peak, contrary to the record in North America. At about 40 Ma, a post-EECO decline was recovered in both hemispheres, but the South American record achieved its greatest diversity then, rather than at the peak of the EECO as in the north. This post-EECO faunal turnover apparently was a response to the changing conditions when global climate was deteriorating toward the Oligocene. Under the progressively more temperate to seasonally arid conditions in South America, this turnover reflected a major change from the more archaic, and more tropical to subtropical-adapted mammals, to the beginning of the ultimately modern South American fauna, achieved completely by the Eocene-Oligocene transition. Interestingly, hypsodonty was achieved by South American cursorial mammals about 15–20 m.y. earlier than in North America. In addition to being composed of essentially different groups of mammals, those of the South American continent seem to have responded to the climatic changes associated with the ECCO and subsequent conditions in a pattern that was initially comparable to, but subsequently different from, their North American counterparts.     

Cenozoic deep-sea ostracods from Maud Rise, Weddell Sea, Antarctica (ODP Site 689): a palaeoceanographical perspective

Cenozoic palaeoceanography of the Maude Rise, Weddell Sea, Antarctica, has been investigated using Palaeocene to Quaternary deep-sea ostracod faunas from 23 samples of ODP Site 689. The abundance of ostracods is high enough only during the Palaeogene (Palaeocene-Oligocene) to allow palaeoceanographical inferences based on changes in diversity, dominance, endemism and faunal turnover (first and last occurrences). The abundance is particularly high throughout the Palaeocene and Eocene, but declines irreversibly near the Eocene/Oligocene boundary. The diversity increases more or less continuously from the Early Palaeocene to the Middle Eocene, and then it generally decreases throughout the remaining part of the Palaeogene (Middle Eocene-Oligocene); an exception is a positive peak in the Shannon-Weaver index in a single sample in the Late Oligocene. No positive peaks in diversity and taxa originations (first occurrences) at c. 40-38 Ma, occurs at Site 689; so the site provides no evidence for the establishment of the psychrosphere at this time. This corroborates similar regional results from an earlier study of benthonic foraminifera. Explanations for this may be related to Late Eocene-Early Oligocene changes in sedimentology and clay-mineralogy (associated with the progressive cooling of the Antarctica) which could have negatively affected abundance and diversity locally at Site 689. Alternatively, by this time, the ostracod fauna could also have been subjected to selective removal (with possible local extinction) of taxa (due to increased ventilation) or to thanatocoenosis dissolution (due to a decrease in temperature and availability of CaCO₃). A further possibility may be related to the fact that Site 689 was at intermediate water depths and may have remained within older water masses near the Eocene/Oligocene boundary. Failing these explanations, the results could indicate that the Late Eocene-Early Oligocene palaeoenvironmental changes in the world oceans were more gradual and occurred over a longer time interval than the global ostracod data show, at least at southern high latitudes.     

The relative importance of body size and paleoclimatic change as explanatory variables influencing lineage diversification rate: an evolutionary analysis of bullhead catfishes (Siluriformes: Ictaluridae)

We applied Bayesian phylogenetics, divergence time estimation, diversification pattern analysis, and parsimony-based methods of ancestral state reconstruction to a combination of nucleotide sequences, maximum body sizes, fossils, and paleoclimate data to explore the influence of an extrinsic (climate change) and an intrinsic (maximum body size) factor on diversification rates in a North American clade of catfishes (Ictaluridae). We found diversification rate to have been significantly variable over time, with significant (or nearly significant) rate increases in the early history of Noturus. Though the latter coincided closely with a period of dramatic climate change at the Eocene-Oligocene boundary, we did not detect evidence for a general association between climate change and diversification rate during the entire history of Ictaluridae. Within Ictaluridae, small body size was found to be a near significant predictor of species richness. Morphological stasis of several species appears to be a consequence of a homoplastic increase in body size. We estimated the maximum standard length of the ictalurid ancestor to be approximately 50 cm, comparable to Eocene ictalurids (Astephus) and similar to modern sizes of Ameiurus and their Asian sister-taxon Cranoglanis. During the late Paleocene and early Eocene, the ictalurid ancestor diversified into the lineages represented by the modern epigean genera. The majority of modern species originated in the Oligocene and Miocene, most likely according to a peripheral isolates model of speciation. We discuss the difficulties of detecting macroevolutionary patterns within a lineage history and encourage the scrutiny of the terminal Eocene climatic event as a direct promoter of diversification.     

Body size in (mostly) mammals: mass,speciation rates and the translation of gamma to alpha diversity on evolutionary timescales

This study tests the hypothesis that high species richness in small-bodied mammals results from higher speciation rates than in clades composed of large-bodied individuals. A right-skewed pattern is evident in size distributions of all mammal groups tested. Gaps between 100 g bins expand smoothly for the global mammal database. Less diverse mammal clades composed of large-sized individuals originated at relatively large size. Mechanisms promoting isolation and higher speciation rates in small mammals include the environmental mosaic, low absolute energy needs, small home range size, stenotopy, and intraspecific competition. A decline in diversity for the smallest size category in some clades suggests there is a lower limit in homoiotherms of about 1.5–2 g, possibly related to high metabolic rate and high surface area to volume ratio. Mammal size diversity from young Canadian ecosystems (≤19,000 years BP) is right-skewed, and diversity of species per unit area is approximately the same as for North America. Diversity and size distributions for mammals and select animal groups from southern Minnesota follow expected right-skewed patterns, suggesting the inverse relationship of body size and speciation rate is universal for complex metazoans. A logistic model is presented integrating γ and α diversity over evolutionary timescales.     

Climate and host‐plant associations shaped the evolution of ceutorhynch weevils throughout the Cenozoic

Using molecular phylogenetic data and methods we inferred divergence times and diversification patterns for the weevil subfamily Ceutorhynchinae in the context of host‐plant associations and global climate over evolutionary time. We detected four major diversification shifts that correlate with both host shifts and major climate events. Ceutorhynchinae experienced an increase in diversification rate at ～53 Ma, during the Early Eocene Climate Optimum, coincident with a host shift to Lamiaceae. A second major diversification phase occurred at the end of the Eocene (～34 Ma). This contrasts with the overall deterioration in climate equability at the Eocene‐Oligocene boundary, but tracks the diversification of important host plant clades in temperate (higher) latitudes, leading to increased diversification rates in the weevil clades infesting temperate hosts. A third major phase of diversification is correlated with the rising temperatures of the Late Oligocene Warming Event (～26.5 Ma); diversification rates then declined shortly after the Middle Miocene Climate Transition (～14.9 Ma). Our results indicate that biotic and abiotic factors together explain the evolution of Ceutorhynchinae better than each of these drivers viewed in isolation.     

Northern Hemisphere origin,transoceanic dispersal,and diversification of Ranunculeae DC. (Ranunculaceae) in the Cenozoic

Aim The role of dispersal versus vicariance for plant distribution patterns has long been disputed. We study the temporal and spatial diversification of Ranunculeae, an almost cosmopolitan tribe comprising 19 genera, to understand the processes that have resulted in the present inter‐continental disjunctions. Location All continents (except Antarctica). Methods Based on phylogenetic analyses of nuclear and chloroplast DNA sequences for 18 genera and 89 species, we develop a temporal–spatial framework for the reconstruction of the biogeographical history of Ranunculeae. To estimate divergence dates, Bayesian uncorrelated rates analyses and four calibration points derived from geological, fossil and external molecular information were applied. Parsimony‐based methods for dispersal–vicariance analysis (diva and Mesquite ) and a maximum likelihood‐based method (Lagrange ) were used for reconstructing ancestral areas. Six areas corresponding to continents were delimited. Results The reconstruction of ancestral areas is congruent in the diva and maximum likelihood‐based analyses for most nodes, but Mesquite reveals equivocal results at deep nodes. Our study suggests a Northern Hemisphere origin for the Ranunculeae in the Eocene and a weakly supported vicariance event between North America and Eurasia. The Eurasian clade diversified between the early Oligocene and the late Miocene, with at least three independent migrations to the Southern Hemisphere. The North American clade diversified in the Miocene and dispersed later to Eurasia, South America and Africa. Main conclusions Ranunculeae diversified between the late Eocene and the late Miocene. During this time period, the main oceanic barriers already existed between continents and thus dispersal is the most likely explanation for the current distribution of the tribe. In the Southern Hemisphere, a vicariance model related to the break‐up of Gondwana is clearly rejected. Dispersals between continents could have occurred via migration over land bridges, such as the Bering Land Bridge, or via long‐distance dispersal.     

Mammalian turnover and community structure in the Paleocene of North America

The effects of faunal turnover on mammalian community structure are evaluated for 17 faunal zones of the North American Paleocene through early Eocene land mammal ages (Puercan through early Wasatchian). Generic disappearances were significantly high at the end of the Puercan, Torrejonian, and Tiffanian land mammal ages, but appearances were significantly high only during the early Puercan. Generic richness rose rapidly in the early Puercan, remained stable throughout most of the Paleocene, and increased from the late Paleocene into the early Eocene. The null hypothesis that generic turnover clustered preferentially according to dentally defined trophic or body size categories could be rejected or attributed to sampling problems for all but the early (Pu0) and late Paleocene (Ti5‐Cf2). Early Paleocene change in community structure most probably represented endemic radiation of mammals into previously unoccupied niches. Community restructuring in the late Paleocene reflected a complex of causes, including climatic wanning, intercontinental dispersal, and competition.     

Phylogenetic distribution and possible evolution of the avian species of the Haemoproteidae

The distribution of species and morphological forms of the avian species of the Haemoproteidae throughout the 26 avian orders is examined. The greatest species diversity and occurrence of different morphological forms is seen among the Coraciiformes and Piciformes; no haemoproteids are recorded from the seven most primitive avian orders. It is suggested that the haemoproteids arose in the late Oligocene/early Eocene at about the same time as Piciformes and Coraciiformes.     

The origin and early evolution of whales: macroevolution documented on the Indian Subcontinent

The origin of whales (order Cetacea) from a four-footed land animal is one of the best understood examples of macroevolutionary change. This evolutionary transition has been substantially elucidated by fossil finds from the Indian subcontinent in the past decade and a half. Here, we review the first steps of whale evolution, i.e. the transition from a land mammal to obligate marine predators, documented by the Eocene cetacean families of the Indian subcontinent: Pakicetidae, Ambulocetidae, Remingtonocetidae, Protocetidae, and Basilosauridae, as well as their artiodactyl sister group, the Raoellidae. We also discuss the influence that the excellent fossil record has on the study of the evolution of organ systems, in particular the locomotor and hearing systems.     

Extinction and replacement among predatory mammals in the North American late Eocene and Oligocene: Tracking a paleoguild over twelve million years

Changes in taxonomic and morphologic diversity within the paleoguild of predatory mammals were explored within a mammalian chronofauna spanning a twelve million year interval, from the latest Eocene to the end of the Oligocene of North America (36–24 ma). The timespan encompassed a modest extinction event among terrestrial mammals (circa 34 ma) followed by a period of relative stability. Morphological diversity was assessed with estimates of body mass, relative tooth size, and tooth shape. Principal component, nearest‐neighbor, and minimum‐spanning‐tree analyses were used to compare morphological diversity and species packing within predator paleoguilds in the mid‐Chadronian (37–34 ma), Orellan (34–32), Whitneyan (32–29.5), and early Arikareean (29.5–24) land mammal ages. Species richness of predators throughout the interval was relatively constant, fluctuating between 15 and 18 total taxa. Moreover, despite significant differences in taxonomic composition and a modest extinction event among terrestrial mammals, morphological diversity within the paleoguild was very similar in the Chadronian and Orellan. In the Whitneyan and especially the early Arikareean, the diversity of feeding adaptations among species declined slightly, largely due to the loss of several highly specialized meat‐eaters (creodonts, nimravids) and the addition of small omnivores (canids).     

Ecomorphological variation in male and female wall lizards and the macroevolution of sexual dimorphism in relation to habitat use

Understanding how phenotypic diversity evolves is a major interest of evolutionary biology. Habitat use is an important factor in the evolution of phenotypic diversity of many animal species. Interestingly, male and female phenotypes have been frequently shown to respond differently to environmental variation. At the macroevolutionary level, this difference between the sexes is frequently analysed using phylogenetic comparative tools to assess variation in sexual dimorphism (SD) across taxa in relation to habitat. A shortcoming of such analyses is that they evaluate the degree of dimorphism itself and therefore they do not provide access to the evolutionary trajectories of each sex. As such, the relative contribution of male and female phenotypes on macroevolutionary patterns of sexual dimorphism cannot be directly assessed. Here, we investigate how habitat use shapes phenotypic diversity in wall lizards using phylogenetic comparative tools to simultaneously assess the tempo and mode of evolution in males, females and the degree of sexual dimorphism. We find that both sexes have globally diversified under similar, but not identical, processes, where habitat use seems to drive macroevolutionary variation in head shape, but not in body size or relative limb length. However, we also observe small differences in the evolutionary dynamics of male and female phenotypes that have a marked impact on macroevolutionary patterns of SD, with important implications for our interpretation of what drives phenotypic diversification within and between the sexes.     

Evolution of fruit characters and dispersal modes in the tropical family Rubiaceae

We investigated the evolution of fruit characters, animals versus abiotic dispersal modes, life forms and geographical distribution, in the large, mostly tropical, family Rubiaceae. As a basis for our analysis we used a phylogenetic tree derived from chloroplast DNA variation. Fleshy fruits have evolved independently at least 12 times in the family. Most of these originations appear to have occurred during Eocene to Oligocene, i.e. the radiation period for some animal taxa (bird families, mammal orders) comprising most extant dispersers of Rubiaceae fruits. Changes of dispersal modes may be of more recent origin in a few cases, e.g. evolution of drupes in some lineages, and shifts from drupes to nuts. The distribution of fruit characters suggested that in several lineages animal-dispersed fruits, such as berries and drupes have remained largely unaltered since the time of origination. This is in contrast to the occurrence of winged seeds in capsules, and pterophylls, i.e. enlarged calyx lobes promoting wind dispersal of fruits, which apparently have shifted more frequently during evolution, indicating a difference in 'phylogenetic plasticity' between modes of animal and wind dispersal.
Animal dispersal was over-represented among genera dominated by shrubs, whereas abiotic dispersal was most prevalent among herbaceous genera. Drupes were over-represented in groups with transoceanic distributions, and on islands, indicating dispersal over long distances, probably by birds. In contrast, no evidence was found to support the view that animal dispersal in general enhances long distance dispersal. We also analysed geographical patterns on the tribal level but these were too complex to yield any resolved area cladograms due to the occurrence of many widespread taxa and area redundancy.