Fossil Lineages Research Articles

The direction of main phenotypic variance as a channel to morphological evolution: case studies in murine rodents

How evolution can be channeled by intrinsic processes such as genetic and developmental networks is a key issue in evolution. Studying the phenotypic variation in a population can shed light on these constraints, because this variation, being the product of these genetic and developmental processes, is the target of both selective screening and random sampling. It could thus act as a “line of least resistance to evolution”. Based on morphometric analysis of molar and mandible shape in several fossil lineages and modern groups of murine rodents, we illustrate here the questions that can be addressed based on this framework. The role intrapopulational variation as line of least resistance to evolution is validated on several lineages. The existence of such preferential direction of evolution can contribute to explain cases of parallel evolution. The underlying mechanisms can be the sharing of similar genetic/developmental pathways but also common functional constraints limiting the range of phenotypic variation to be explored. Comparing directions of intrapopulation variance to the course of interpopulation evolution can thus be of help to bridge several evolutionary levels and contribute to an integrated vision of the phenotypic evolution. Download the complete Yellow Book on Virtual Morphology and Evolutionary Morphometrics in the new millenium.

Paleotree: an R package for paleontological and phylogenetic analyses of evolution

Summary1. paleotree is a library of functions for the R statistical computing environment dedicated to analyses that combine paleontological and phylogenetic data sets, particularly the time‐scaling of phylogenetic trees, which include extinct fossil lineages.2. The functions included in this library focus on simulating paleontological data sets, measuring sampling rates, time‐scaling cladograms of fossil taxa and plotting historical diversity curves.3. I describe the capabilities and analytical basis of the functions in paleotree by presenting two examples. The first example showcases the simulation capabilities and plotting the output as diversity curves. The second example demonstrates time‐scaling a cladogram of fossil taxa and estimating sampling rates and completeness from temporal ranges.

Rates of anagenetic evolution and selection intensity in Middle and Upper Ordovician species of the bryozoan genusPeronopora

Evolutionary rates and selection intensities in eight cladistically defined species-level evolutionary sequences of the Middle and Upper Ordovician bryozoan genusPeronoporawere calculated for comparison with values published for fossil and living taxa. Calculations were restricted to statistically significant unidirectional segments of anagenetic series to minimize the mixing of different modes, directions, and rates of evolutionary change.Rates and selection intensities ranged from 10−7to 10−6darwins and from 10−6to 10−5haldanes. Across characters, the weighted mean evolutionary rate equaled 5.86 × 10−7darwins and the mean selection intensity was 6.44 × 10−7. Mean rates of 2.15 × 10−6, 4.31 × 10−6, and 8.61 × 10−6haldanes, and corresponding mean selection intensities equaling 2.39 × 10−6, 4.78 × 10−6, and 9.56 × 10−6, were calculated for generation lengths of 0.5, 1, and 2 years, respectively.The magnitudes of positive and negative evolutionary rates and selection intensities do not differ statistically, individual characters display no consistent pattern of positive or negative values, and no character complexes were detectable. A mosaic pattern of change occurs across characters in evolutionary sequences.Eighty percent of analyzed evolutionary series were multispecies lineages. Both individual and mean values provide direct estimates of the rates of evolution within those lineages at the moment of speciation.Rates of anagenetic evolution inPeronoporawere low and similar to published rates for a variety of fossil protists, invertebrates, and vertebrates. However, earlier rate calculations did not isolate the effect of unidirectional anagenesis from that of stasis, random walks, trend reversals, or rate variations. Eight percent of characters inPeronoporaproduced anagenetic series that were statistically significant, a percentage similar to the 5% calculated in a study of 251 sequences of evolving traits in 53 fossil lineages (Hunt 2007). Stasis and mutation-drift are the most common patterns detectable in the fossil record, although anagenesis remains a potentially important force in shaping the course of both micro- and macroevolution.

Large‐scale evolutionary trends of Acrochordiceratidae Arthaber, 1911 (Ammonoidea, Middle Triassic) and Cope’s rule

Abstract: Directed evolution of life through millions of years, such as increasing adult body size, is one of the most intriguing patterns displayed by fossil lineages. Processes and causes of such evolutionary trends are still poorly understood. Ammonoids (externally shelled marine cephalopods) are well known to have experienced repetitive morphological evolutionary trends of their adult size, shell geometry and ornamentation. This study analyses the evolutionary trends of the family Acrochordiceratidae Arthaber, 1911 from the Early to Middle Triassic (251–228 Ma). Exceptionally large and bed‐rock‐controlled collections of this ammonoid family were obtained from strata of Anisian age (Middle Triassic) in north‐west Nevada and north‐east British Columbia. They enable quantitative and statistical analyses of its morphological evolutionary trends. This study demonstrates that the monophyletic clade Acrochordiceratidae underwent the classical evolute to involute evolutionary trend (i.e. increasing coiling of the shell), an increase in its shell adult size (conch diameter) and an increase in the indentation of its shell suture shape. These evolutionary trends are statistically robust and seem more or less gradual. Furthermore, they are nonrandom with the sustained shift in the mean, the minimum and the maximum of studied shell characters. These results can be classically interpreted as being constrained by the persistence and common selection pressure on this mostly anagenetic lineage characterized by relatively moderate evolutionary rates. Increasing involution of ammonites is traditionally interpreted by increasing adaptation mostly in terms of improved hydrodynamics. However, this trend in ammonoid geometry can also be explained as a case of Cope’s rule (increasing adult body size) instead of functional explanation of coiling, because both shell diameter and shell involution are two possible paths for ammonoids to accommodate size increase.

Prophaenognatha, a New Aclopinae Genus from the Yixian Formation, China and Its Phylogenetic Position Based on Morphological Characters (Coleoptera: Scarabaeidae)

Abstract:Prophaenognatha robusta gen. et sp. nov. (Scarabaeoidea: Scarabaeidae: Aclopinae), the best‐preserved aclopine fossil so far, is described and illustrated from the Upper Jurassic‐Lower Cretaceous Yixian Formation of the Jehol Biota, western Liaoning Province, NE China. The key to extinct and extant genera of Aclopinae is given and the monophyly of extant and fossil Aclopinae lineages is supported by five character states. The new taxon provides evidence about the evolution of Scarabaeoidea with its phylogenetic position inferred based on 68 morphological characters.

Fluctuating selection: the perpetual renewal of adaptation in variable environments

Darwin insisted that evolutionary change occurs very slowly over long periods of time, and this gradualist view was accepted by his supporters and incorporated into the infinitesimal model of quantitative genetics developed by R. A. Fisher and others. It dominated the first century of evolutionary biology, but has been challenged in more recent years both by field surveys demonstrating strong selection in natural populations and by quantitative trait loci and genomic studies, indicating that adaptation is often attributable to mutations in a few genes. The prevalence of strong selection seems inconsistent, however, with the high heritability often observed in natural populations, and with the claim that the amount of morphological change in contemporary and fossil lineages is independent of elapsed time. I argue that these discrepancies are resolved by realistic accounts of environmental and evolutionary changes. First, the physical and biotic environment varies on all time-scales, leading to an indefinite increase in environmental variance over time. Secondly, the intensity and direction of natural selection are also likely to fluctuate over time, leading to an indefinite increase in phenotypic variance in any given evolving lineage. Finally, detailed long-term studies of selection in natural populations demonstrate that selection often changes in direction. I conclude that the traditional gradualist scheme of weak selection acting on polygenic variation should be supplemented by the view that adaptation is often based on oligogenic variation exposed to commonplace, strong, fluctuating natural selection.

Qualitative Comparison of the Cranio‐Dental Osteology of the Extant Elephants,Elephas Maximus(Asian Elephant) andLoxodonta africana(African Elephant)

Few osteological descriptions of the extant elephants and no detailed morphological comparison of the two genera, Elephas and Loxodonta, have been done in recent years. In this study, 786 specimens of extant elephants (crania, mandibles, and molars) were examined for characters unique to each species. Differences between sexes in each species were described, as well as differences between subspecies of each species. Striking differences in morphology were noted between sexes of both elephants and between subspecies, which may complement current genetic studies, the focus of which is to determine division at the subspecies or species level, particularly differences between the savanna elephant (Loxodonta africana africana) and the forest elephant (Loxodonta africana cyclotis). In addition, examination of the two living elephants provides an excellent dataset for identifying phylogenetic characters for use in examining evolutionary relationships within and between fossil lineages of elephantids.

The effects of fossil placement and calibration on divergence times and rates: An example from the termites (Insecta: Isoptera)

Among insects, eusocial behavior occurs in termites, ants, some bees and wasps. Isoptera and Hymenoptera convergently share social behavior, and for both taxa its evolution remains poorly understood. While dating analyses provide researchers with the opportunity to date the origin of eusociality, fossil calibration methodology may mislead subsequent ecological interpretations. Using a comprehensive termite dataset, we explored the effect of fossil placement and calibration methodology. A combined molecular and morphological dataset for 42 extant termite lineages was used, and a second dataset including these 42 taxa, plus an additional 39 fossil lineages for which we had only morphological data. MrBayes doublet-model analyses recovered similar topologies, with one minor exception (Stolotermitidae is sister to the Hodotermitidae, s.s., in the 42-taxon analysis but is in a polytomy with Hodotermitidae and (Kalotermitidae + Neoisoptera) in the 81-taxon analysis). Analyses using the r8s program on these topologies were run with either minimum/maximum constraints (analysis a = 42-taxon and analysis c = 81-taxon analyses) or with the fossil taxon ages fixed (ages fixed to be the geological age of the deposit from which they came, analysis b = 81-taxon analysis). Confidence intervals were determined for the resulting ultrametric trees, and for most major clades there was significant overlap between dates recovered for analyses A and C (with exceptions, such as the nodes Neoisoptera, and Euisoptera). With the exception of isopteran and eusiopteran node ages, however, none of the major clade ages overlapped when analysis B is compared with either analysis A or C. Future studies on Dictyoptera should note that the age of Kalotermitidae was underestimated in absence of kalotermitid fossils with fixed ages.

A GENERAL FRAMEWORK FOR THE ANALYSIS OF PHENOTYPIC TRAJECTORIES IN EVOLUTIONARY STUDIES

Many evolutionary studies require an understanding of phenotypic change. However, while analyses of phenotypic variation across pairs of evolutionary levels (populations or time steps) are well established, methods for testing hypotheses that compare evolutionary sequences across multiple levels are less developed. Here we describe a general analytical procedure for quantifying and comparing patterns of phenotypic evolution. The phenotypic evolution of a lineage is defined as a trajectory across a set of evolutionary levels in a multivariate phenotype space. Attributes of these trajectories (their size, direction, and shape), are quantified, and statistically compared across pairs of taxa, and a summary statistic is used to determine the extent to which patterns of phenotypic evolution are concordant across multiple taxa. This approach provides a direct quantitative description of how patterns of phenotypic evolution differ, as well as a statistical assessment of the degree of repeatability in the evolutionary responses to selection among taxa. We describe how this approach can quantify phenotypic trajectories from many ecological and evolutionary processes, whose data encode multivariate characterizations of the phenotype, including: phenotypic plasticity, ecological selection, ontogeny and growth, local adaptation, and biomechanics. We illustrate the approach by examining the phenotypic evolution of several fossil lineages of Globorotalia.

Directional evolution in the conodontPterospathodus

The excellent fossil record of conodonts represents an ideal, yet underutilized, resource for resolving fundamental issues of pattern and process in evolutionary theory. However, this potential has not been exploited because the quantitative understanding of the evolution of conodont element morphology is limited. This work applies standardized morphometric protocols to skeletal elements belonging to the conodontPterospathodus, derived from a densely sampled section from Estonia. It has established a robust quantitative framework for morphological variation inPterospathodus, permitting statistical analysis of the current qualitative hypotheses of evolutionary pattern within this genus for the first time. Apparent directional trends were statistically compared with patterns expected for directional evolution, an unbiased random walk and stasis, using maximum-likelihood model fitting, rescaled range analysis, and the runs test. Results confirmed the presence of trends in size and shape change through time, providing an example of convincing directional morphological change in a fossil lineage. The morphometric analyses have also allowed quantitative investigation of ontogenetic processes inPterospathodus, suggesting that allometric repatterning was the proximal mechanism responsible for mediating the observed shifts in morphology through time. The results have demonstrated that conodonts represent an important resource for understanding evolutionary pattern and process in the fossil record.

Inferring evolutionary modes in a fossil lineage (Bryozoa:Peronopora) from the Middle and Late Ordovician

Recent analytical advances have permitted quantitative evaluations of evolutionary mode in populations of fossil organisms by providing tests of the null hypothesis that patterns of stratigraphic character variation do not differ from the expectations of a random walk. If the hypothesis can be rejected, then stasis and anagenesis represent alternative evolutionary modes discernable using values of the Hurst estimate. We used this approach to evaluate evolutionary mode in the bryozoan genusPeronoporaacross 34 characters in eight unbranched, cladistically defined, evolutionary sequences. Eight monophyletic crown species and eight paraphyletic (phenetically distinct) metaspecies constitute 16 species-rank taxa within the genus.In seven of 15 species-rank transitions that had adequate sample sizes, significant character state changes—both phyletic gradualism and punctuated equilibrium—coincided with speciation events 11% of the time and were limited to more derived, crownward, ancestor-descendant pairs. Each of the 34 measured characters exhibited instances of transpecific stasis or anagenesis. Anagenesis of some characters persisted across unbranched lineages over 13 species (i.e., across 12 speciation events), whereas character stasis continued through unbranched lineages in up to 16 species (i.e., persisted unchanged across all 15 speciation events). Transpecific stasis and anagenesis were recognizable in over one-half of the data set, with stasis being approximately twice as common as anagenesis.Across all character state transitions, approximately one-half reflect stasis, 30% anagenesis, and 20% could not be differentiated from a random walk. Similarly, across species and metaspecies characterized by a single intraspecific mode, stasis was twice as common as anagenesis and three times more common than undifferentiated random walks. The remaining instances of multiple intraspecific evolutionary modes occurred more commonly within metaspecies than within species. This difference might reflect the more frequent presence of unrecognized cryptic species or subspecies within metaspecies ofPeronopora.Instantaneous rates of evolution can be estimated both within and between species ofPeronoporafor characters displaying anagenesis, potentially providing quantitative insights into evolutionary changes within the lineage.

The fossil crown wasp Electrostephanus petiolatus Brues in Baltic Amber (Hymenoptera, Stephanidae): designation of a neotype, revised classification, and a key to amber Stephanidae

The fossil crown wasp Electrostephanus petiolatus Brues comb. rev. (Stephanidae, Electrostephaninae) is redescribed from a single male preserved in middle Eocene Baltic Amber. The holotype was lost or destroyed around the time of World War II and subsequent interpretations of its identity have been based solely on the brief descriptive comments provided by Brues in his original account. The new specimen matches the original description and illustration provided by Brues in every detail and we hereby consider them to be conspecific, selecting the specimen as a neotype for the purpose of stabilizing the nomenclature for this fossil species. This neotype exhibits a free first metasomal tergum and sternum, contrary to the assertion of previous workers who indicated these to be fused. Accordingly, does indeed belong to the genus Electrostephanus Brues rather than to Denaeostephanus Engel & Grimaldi (Stephaninae). Electrostephanus petiolatus is transferred to a new subgenus, Electrostephanodes n. subgen., based on its elongate pseudo-petiole and slender gaster, but may eventually warrant generic status as the phylogenetic placement of these fossil lineages continues to be clarified. A revised key to the Baltic amber crown wasps is provided.

Evolutionary Patterns Within Fossil Lineages: Model-Based Assessment of Modes, Rates, Punctuations and Process

Patterns of phenotypic change documented in the fossil record offer the only direct view scientists have of evolutionary transitions arrayed over significant durations of time. What lessons should be drawn from these data, however, has proven to be rather contentious. Although we as paleontologists have made great progress in documenting the geological record of phenotypic evolution with greater thoroughness and sophistication, these successes have been limited by the use of verbal models of how phenotypes change. Descriptive terms such as “gradual” have been understood differently by different authors, and this has led to completely incompatible summary statements about the fossil record of morphological evolution. Here I argue that the solution to this ambiguity lies in insisting that different evolutionary interpretations be represented as explicit, statistical models of evolution. With such an approach, the powerful machinery of likelihood-based inference can be help resolve long-standing paleontological questions.Here I first review this approach and some aspects of its implementation. Then, I show how this approach leads to new traction on important issues in evolutionary paleobiology, including: understanding modes of evolution and determining their relative importance, separating evolutionary mode from tempo, assessing the evidence for hypotheses of punctuated change, and detecting adaptive evolution in the fossil record.

Molecules, morphology and fossils: a comprehensive approach to odonate phylogeny and the evolution of the odonate wing.

We undertook a comprehensive morphological and molecular phylogenetic analysis of dragonfly phylogeny, examining both extant and fossil lineages in simultaneous analyses. The legitimacy of higher-level family groups and the phylogenetic relationship between families were tested. Thirteen families were supported as monophyletic (Aeshnidae, Calopterygidae, Chlorocyphidae, Euphaeidae, Gomphidae, Isostictidae, Lestidae, Libellulidae, Petaluridae, Platystictidae, Polythoridae, Pseudostigmatidae and Synthemistidae) and eight as non-monophyletic (Amphipterygidae, Coenagrionidae, Corduliidae, Megapodagrionidae, Protoneuridae and Synlestidae), although Perilestidae and Platycnemididae were recovered as monophyletic under Bayesian analyses. Nine families were represented by one species, thus monophyly was not tested (Epiophlebiidae, Austropetaliidae, Chlorogomphidae, Cordulegastridae, Macromiidae, Chorismagrionidae, Diphlebiidae, Lestoideidae and Pseudolestidae). Epiprocta and Zygoptera were recovered as monophyletic. Ditaxinerua is supported as the sister lineage to Odonata, Epiophlebiidae and the lestid-like damselflies are sister to the Epiprocta and Zygoptera, respectively. Austropetaliidae + Aeshnidae is the sister lineage to the remaining Anisoptera. Tarsophlebia's placement as sister to Epiprocta or as sister to Epiprocta + Zygoptera was not resolved. Refinements are made to the current classification. Fossil taxa did not seem to provide signals crucial to recovering a robust phylogeny, but were critical to understanding the evolution of key morphological features associated with flight. Characters associated with wing structure were optimized revealing two wing character complexes: the pterostigma-nodal brace complex and the costal wing base & costal-ScP junction complex. In turn, these two complexes appear to be associated; the pterostigma-nodal brace complex allowing for further modification of the wing characters comprised within the costal wing base & costal-ScP junction complex leading the modern odonate wing. © The Willi Hennig Society 2008.

The Phylogeny of Archostemata (Coleoptera) and new Approaches in Insect Morphology Zur Phylogenie der Archostemata (Coleoptera) und neue Ansätze zur Insektenmorphologie

This study gives an overview of recent developments and results in the morphological and phylogenetic study of Archostemata, and a short account of innovative morphological techniques such as for instance micro computer tomography (μ-CT) and computer based 3-dimensional reconstructions. Archostemata are a small relict group of beetles. They display a mosaic pattern of highly derived characters, mainly of the head, and of plesiomorphic features, mainly of the thorax. The results of recent cladistic analyses suggest that Ommatidae, Cupedidae, Micromalthidae, Crowsoniellidae and Jurodidae (Sikhotealinia and †Jurodes), and the extinct families †Schizophoridae, †Catiniidae, and tAdemosynidae form a clade Archostemata. However, the placement of Jurodidae and the three fossil groups remains ambiguous, mainly due to lack of reliable morphological data. Within Archostemata, Ommatidae are probably the most basal group and recent cladistic analyses suggest that Jurodidae may form the sistergroup of a clade comprising Micromalthidae, Crowsoniellidae, †Schizophoridae, tCatiniidae, and †Ademosynidae. Archostemata is the sistergroup of the remaining three beetle suborders. All Permian fossil lineages traditionally assigned to Archostemata belong to the stem group of Coleoptera, with a branching pattern (†Tshekardocoleidae + (†Permocupedidae + (†Rhombocoleidae + (tTriadocupedinae + (Coleoptera s.str. [=crown group]))))). The reconstruction of the phylogeny of Archostemata is still impeded by a severe lack of material and morphological data. Intensive collecting activities should have high priority, combined with the application of traditional and modem morphological methods. Innovative techniques have given new and strong impulses to insect morphology in the last years.

EVOLUTION TOWARD A NEW ADAPTIVE OPTIMUM: PHENOTYPIC EVOLUTION IN A FOSSIL STICKLEBACK LINEAGE

Natural selection has almost certainly shaped many evolutionary trajectories documented in fossil lineages, but it has proven difficult to demonstrate this claim by analyzing sequences of evolutionary changes. In a recently published and particularly promising test case, an evolutionary time series of populations displaying armor reduction in a fossil stickleback lineage could not be consistently distinguished from a null model of neutral drift, despite excellent temporal resolution and an abundance of indirect evidence implicating natural selection. Here, we revisit this case study, applying analyses that differ from standard approaches in that: (1) we do not treat genetic drift as a null model, and instead assess neutral and adaptive explanations on equal footing using the Akaike Information Criterion; and (2) rather than constant directional selection, the adaptive scenario we consider is that of a population ascending a peak on the adaptive landscape, modeled as an Orstein-Uhlenbeck process. For all three skeletal features measured in the stickleback lineage, the adaptive model decisively outperforms neutral evolution, supporting a role for natural selection in the evolution of these traits. These results demonstrate that, at least under favorable circumstances, it is possible to infer in fossil lineages the relationship between evolutionary change and features of the adaptive landscape.

The relative importance of directional change, random walks, and stasis in the evolution of fossil lineages

The nature of evolutionary changes recorded by the fossil record has long been controversial, with particular disagreement concerning the relative frequency of gradual change versus stasis within lineages. Here, I present a large-scale, statistical survey of evolutionary mode in fossil lineages. Over 250 sequences of evolving traits were fit by using maximum likelihood to three evolutionary models: directional change, random walk, and stasis. Evolution in these traits was rarely directional; in only 5% of fossil sequences was directional evolution the most strongly supported of the three modes of change. The remaining 95% of sequences were divided nearly equally between random walks and stasis. Variables related to body size were significantly less likely than shape traits to experience stasis. This finding is in accord with previous suggestions that size may be more evolutionarily labile than shape and is consistent with some but not all of the mechanisms proposed to explain evolutionary stasis. In general, similar evolutionary patterns are observed across other variables, such as clade membership and temporal resolution, but there is some evidence that directional change in planktonic organisms is more frequent than in benthic organisms. The rarity with which directional evolution was observed in this study corroborates a key claim of punctuated equilibria and suggests that truly directional evolution is infrequent or, perhaps more importantly, of short enough duration so as to rarely register in paleontological sampling.

Phylogeny and Geological History of the Cynipoid Wasps (Hymenoptera: Cynipoidea)

Abstract The geological history of the wasp superfamily Cynipoidea is reviewed, with the description of various new taxa, being mostly in Late Cretaceous amber from New Jersey and Canada. The various fossil lineages are incorporated into a phylogenetic analysis of the superfamily, and their implications for understanding the evolution of the group are explored. The following new taxa or taxonomic changes are proposed (authorship of all taxa is Liu and Engel): Protimaspidae, new family; Stolamissidae, new family; Stolamissus, new genus; Stolamissus mirabilis, new species; Proliopterinae, new subfamily; Proliopteron, new genus; Proliopteron redactus, new species; Goeraniinae, new subfamily; Goerania, new genus; Goerania petiolata, new species; Micropresbyteria, new genus; Micropresbyteria caputipressa, new species; Anteucoila, new genus; Anteucoila delicia, new species; Jerseucoila, new genus; Jerseucoila plesiosoma, new species; Syneucoila, new genus; Syneucoila magnifica, new species; Tanaoknemus, new gen...

Molecular dating of the ‘Gondwanan’ plant family Proteaceae is only partially congruent with the timing of the break‐up of Gondwana

AbstractAim The flowering plant family Proteaceae is putatively of Gondwanan age, with modern and fossil lineages found on all southern continents. Here we test whether the present distribution of Proteaceae can be explained by vicariance caused by the break‐up of Gondwana.Location Africa, especially southern Africa, Australia, New Zealand, South America, New Caledonia, New Guinea, Southeast Asia, Sulawesi, Tasmania.Methods We obtained chloroplast DNA sequence data from therbcL gene, therbcL‐atpB spacer, and theatpB gene from leaf samples of forty‐five genera collected from the field and from living collections. We analysed these data using Bayesian phylogenetic and molecular dating methods, with five carefully selected fossil calibration points to obtain age estimates for the nodes within the family.Results Four of eight trans‐continental disjunctions of sister groups within our sample of the Proteaceae post‐date the break‐up of Gondwana. These involve independent lineages, two with an Africa‐Australia disjunction, one with an Africa–South America disjunction, and one with a New Zealand–Australasia disjunction. The date of the radiation of the bird‐pollinated Embothriinae corresponds approximately to the hypothesized date of origin of nectar‐feeding birds in Australia.Main conclusions The findings suggest that disjunct distributions in Proteaceae result from both Gondwanan vicariance and transoceanic dispersal. Our results imply that ancestors of some taxa dispersed across oceans rather than rafting with Gondwanan fragments as previously thought. This finding agrees with other studies of Gondwanan plants in dating the divergence of Australian, New Zealand and New Caledonian taxa in the Eocene, consistent with the existence of a shared, ancestral Eocene flora but contrary to a vicariance scenario based on accepted geological knowledge.

Fossil ghost ranges are most common in some of the oldest and some of the youngest strata.

Biologists routinely compare inferences about the order of evolutionary branching (phylogeny) with the order in which groups appear in the fossil record (stratigraphy). Where they conflict, ghost ranges are inferred: intervals of geological time where a fossil lineage should exist, but for which there is no direct evidence. The presence of very numerous and/or extensive ghost ranges is often believed to imply spurious phylogenies or a misleadingly patchy fossil record, or both. It has usually been assumed that the frequency of ghost ranges should increase with the age of rocks. Previous studies measuring ghost ranges for whole trees in just a small number of temporal bins have found no significant increase with antiquity. This study uses a much higher resolution approach to investigate the gappiness implied by 1,000 animal and plant cladograms over 77 series and stages of the Phanerozoic. It demonstrates that ghost ranges are indeed relatively common in some of the oldest strata. Surprisingly, however, ghost ranges are also relatively common in some of the youngest, fossil-rich rocks. This pattern results from the interplay between several complex factors and is not a simple function of the completeness of the fossil record. The Early Palaeozoic record is likely to be less organismically and stratigraphically complete, and its fossils -- many of which are invertebrates-may be more difficult to analyse cladistically. The Late Cenozoic is subject to the pull of the Recent, but this accounts only partially for the increased gappiness in the younger strata.