Radiation Of Angiosperms Research Articles

Possible long-proboscid insect pollinators from the Early Permian of Russia

Insect pollination is one of the hallmarks of flowering plants.1 Bees, moths, flies, and some other pollinators evolved elongate siphonate mouthparts for sucking concealed nectar and occasionally other liquids.2 However, it is clear from the fossil record that insects with similar adaptations appeared long before the mid-Cretaceous radiation of angiosperms. These insects most probably used their proboscis to reach pollination drops and other sugary fluids that were hidden in the cones of extinct gymnosperms, pollinating them in the process.3-6 The vast majority of these gymnosperm-associated long-proboscid insects have been reported from the Middle Jurassic to the Early Cretaceous, i.e., the time interval that immediately predated the advent of flowering plants.7 By contrast, the Paleozoic stage of the co-evolution between long-proboscid insect pollinators and plants has remained poorly understood. Here, we report a putative pollination mutualism involving long-proboscid holometabolous insects (Panorpida: Protomeropidae) from the Early Permian of Russia (ca. 283-273 Ma). Their elongate mouthparts have very similar morphology to those of some present-day nectarivorous Coleoptera and Hymenoptera and probably served to imbibe micropylar secretions from the semi-closed ovulate organs of the gymnosperms of a peltaspermalean affinity that have been found in the same locality. This is the earliest record of insects with siphonate-like mouthparts, which could indicate that the complex interactions between pollinators and gymnosperms predate the first flowering plants by over 100 Ma.

Further evidence for Cretaceous wildfires: macro-charcoal from the Malha Formation at Wadi Budra, west-central Sinai, Egypt

Abstract Fossil evidence for wildfires, in form of fossil charcoal, is known from a large number of Cretaceous localities worldwide and it has repeatedly been argued that wildfires were connected to the evolution and radiation of angiosperms during this period. The present study provides new evidence (in form of macro-charcoal) for the occurrence of wildfires during deposition of the Lower Cretaceous (pre-Aptian) Malha Formation at Wadi Budra of the Sinai Peninsula, Egypt. Despite growing evidence for the worldwide occurrence of wildfires during the Cretaceous, the available database for pre-Aptian wildfires is still rather scarce for large regions when seen on a global scale, hampering causal interpretations concerning the interactions between fire ecology and the evolution of ecosystems during these stages.

Angiosperm pollen assemblages from the Lower Cretaceous (Barremian–lower Aptian) of offshore Saudi Arabia and their implications for early patterns of angiosperm radiation

Early flowering plants constituted a minor component of the Early Cretaceous conifer- and fern- dominated flora. However, their pollen provides a rich, albeit incomplete, record of the group's early evolutionary history. Palynological analysis of Barremian–lower Aptian successions from the Biyadh and Shu'aiba formations in the Arabian Gulf reveals remarkably high angiosperm diversity. While Chloranthaceae, magnoliids, monocots, eudicots, and other “basal” groups represent the bulk of flowering plants, pollen with uncertain affinities is also a significant component of the angiosperm assemblage. Analysis of the palaeobiogeographic distribution of angiosperm pollen during the late Barremian–early Aptian allowed us to discern three groups of angiosperms. The first group, including Clavatipollenites, produced pollen with a near-cosmopolitan distribution. The second group, including Stellatopollis, had a somewhat restricted distribution in northern Gondwana and western Laurasia. The pollen distribution of the third group, which includes Dichastopollenites, is restricted to central and/or northeastern Gondwana. These varied patterns of palaeobiogeographical spread of early angiosperms reflect different migration and colonisation abilities. When compared with coeval palynological successions from other Gondwanan localities, the composition and diversity of the Arabian angiosperm assemblages support early hypotheses on the radiation of angiosperms that identify northeastern Gondwana as one of the most important centres of angiosperm diversification.The following new taxa are described: Splitipollis gen. nov., Splitipollis reticulatus sp. nov., Tucanopollis doylei sp. nov., Pennipollis spinosus sp. nov., Clavamonocolpites woodii sp. nov., and Retimonoporites arabiensis sp. nov.

New insights into the moss genus Vetiplanaxis with a description of V. obtusus sp. nov. from the mid-Cretaceous Kachin amber, Myanmar

Molecular phylogenetic analyses indicate that during the Cretaceous Terrestrial Revolution (KTR) around 125–80 Ma, the rapid rise and radiation of angiosperms probably triggered the diversification of mosses and substantial changes of their lineage composition. However, moss fossils which could substantiate these findings are generally rare in the Cretaceous. In this study, we investigate several sterile gametophyte fragments of mosses preserved in mid-Cretaceous Kachin amber from Myanmar. We describe a new sterile shoot as Vetiplanaxis obtusus sp. nov. (Hypnodendrales), make an emended description of V. pyrrhobryoides Bell based on additional fossil materials, and identify a linear-lanceolate leaf as V. cf. longiacuminatus Hedenäs et al. We confirm again the presence of geminate teeth in leaf margin of the above three species studied here, and report the presence of hair-like rhizoids in stem. The phyllotaxis in the species of Vetiplanaxis with complanate shoot is explained as pseudo-tetrastichous, really octostichous, formed by two right-handed Fibonacci spirals. Our findings provide new insights into the circumscription of the Cretaceous moss genus Vetiplanaxis, and add new evidence to indicate that there was a diverse pleurocarpous moss flora in the mid-Cretaceous Kachin amber forest of Myanmar.

Exceptional evolutionary lability of flower-like inflorescences (pseudanthia) in Apiaceae subfamily Apioideae.

PremisePseudanthia are widespread and have long been postulated to be a key innovation responsible for some of the angiosperm radiations. The aim of our study was to analyze macroevolutionary patterns of these flower‐like inflorescences and their potential correlation with diversification rates in Apiaceae subfamily Apioideae. In particular, we were interested to investigate evolvability of pseudanthia and evaluate their potential association with changes in the size of floral display.MethodsThe framework for our analyses consisted of a time‐calibrated phylogeny of 1734 representatives of Apioideae and a morphological matrix of inflorescence traits encoded for 847 species. Macroevolutionary patterns in pseudanthia were inferred using Markov models of discrete character evolution and stochastic character mapping, and a principal component analysis was used to visualize correlations in inflorescence architecture. The interdependence between net diversification rates and the occurrence of pseudocorollas was analyzed with trait‐independent and trait‐dependent approaches.ResultsPseudanthia evolved in 10 major clades of Apioideae with at least 36 independent origins and 46 reversals. The morphospace analysis recovered differences in color and compactness between floral and hyperfloral pseudanthia. A correlation between pseudocorollas and size of inflorescence was also strongly supported. Contrary to our predictions, pseudanthia are not responsible for variation in diversification rates identified in this subfamily.ConclusionsOur results suggest that pseudocorollas evolve as an answer to the trade‐off between enlargement of floral display and costs associated with production of additional flowers. The high evolvability and architectural differences in apioid pseudanthia may be explained on the basis of adaptive wandering and evolutionary developmental biology.

Onset of Late Cretaceous diversification in Europe\u2019s freshwater gastropod fauna links to global climatic and biotic events

The Mesozoic rise of the European freshwater gastropod fauna is still poorly understood. Compared to the well documented Cenozoic history, little is known about the patterns and processes underlying the early diversification preceding their extinction crisis at the K–Pg boundary. We assess what is probably a first pulse of diversification of the Cenozoic-type fauna in the Late Cretaceous along with the potential abiotic and biotic controls for shifts in species diversification. We find strong support that the increase in the speciation rate in the Santonian (~ 85 Myr ago) is linked to a global sea level rise, which caused extensive flooding of continental areas and the formation of vast brackish-water ecosystems. The following decline of the speciation rate coincides with a rise in diversity and reflects increasing interspecific competition. The peak in the speciation rate postdates the Cenomanian–Turonian Thermal Maximum, which probably limited the potential for diversification among freshwater gastropods due to ecological constraints. The peak coincides moreover with the end phase of the Cretaceous Terrestrial Revolution, which sparked the radiation of angiosperms. The expansion and diversification of flowering plants, being an important food source for freshwater gastropods today, could have formed a necessary basis for gastropod diversification.

Origin and evolution of green plants in the light of key evolutionary events.

Green plants (Viridiplantae) are ancient photosynthetic organisms that thrive both in aquatic and terrestrial ecosystems, greatly contributing to the changes in global climates and ecosystems. Significant progress has been made toward understanding the origin and evolution of green plants, and plant biologists have arrived at the consensus that green plants first originated in marine deep-water environments and later colonized fresh water and dry land. The origin of green plants, colonization of land by plants and rapid radiation of angiosperms are three key evolutionary events during the long history of green plants. However, the comprehensive understanding of evolutionary features and molecular innovations that enabled green plants to adapt to complex and changeable environments are still limited. Here, we review current knowledge of phylogenetic relationships and divergence times of green plants, and discuss key morphological innovations and distinct drivers in the evolution of green plants. Ultimately, we highlight fundamental questions to advance our understanding of the phenotypic novelty, environmental adaptation, and domestication of green plants.

Sawflies out of Gondwana: phylogenetics and biogeography of Argidae (Hymenoptera)

ABSTRACTWe present the first phylogenetic hypothesis for the cosmopolitan family Argidae based on both molecular and morphological data. Furthermore, we present a biogeographic scenario based on a dated phylogeny and interpret the evolutionary history of the family. Information from sequences of eight genes is analysed to reconstruct the phylogeny of the Argidae based on maximum likelihood and Bayesian inference. Total evidence Bayesian analyses are also conducted, combining the molecular dataset with data from adult and larval morphology. For the historical biogeographic reconstruction, divergence times are estimated using node dating with uncorrelated relaxed‐clock analysis, and ancestral biogeographical distributions are estimated applying a Dispersal Extinction Cladogenesis model and a Bayesian binary model. Argidae s.s. is retrieved as monophyletic in all analyses and the clade Zenargidae + (Argidae + Pergidae) is better supported when combining molecular and morphological characters, and when excluding the saturated third codon position in the molecular analysis. Within Argidae, two large clades corresponding to the subfamilies Arginae and Sterictiphorinae sensu Benson are retrieved as monophyletic. The ancestral distribution of Arginae and Sterictiphorinae is estimated to be the Australian and Neotropical regions. Divergence of Argidae‐Pergidae and Arginae‐Sterictiphorinae is estimated to occur in the middle‐upper Jurassic before or during the east‐west Gondwana breakup. Diversification of Argidae may be associated with the radiation of angiosperms in the Early Cretaceous, especially for the Neotropical Sterictiphorinae after the separation of South America and Africa. Arginae were probably introduced to the northern hemisphere by dispersal to Africa and/or India and subsequent continental collision with Eurasia in the Cenozoic. The occurrence of Sterictiphorinae in the northern hemisphere is more difficult to explain. Maternal care and brood guarding behaviour evolved independently in Argidae and Pergidae, with a single origin in a subclade (Dielocerini) of Sterictiphorinae.

Mitogenomic data elucidate the phylogeny and evolution of life strategies in Dermestidae (Coleoptera)

AbstractDermestidae (Bostrichoidea) exploit diverse food sources including fungal mycelia, but notably they as saprophagous, feeding on decomposing and dried flesh and keratin of animals and plants. Some of them live in spider webs, vertebrate and social insect nests, while others cause damage in human dwellings. Here, we use mitogenomics to reconstruct their phylogeny and evolution of life history strategies. We recovered serial splits of Orphilinae, Thorictinae + Dermestinae, Attageninae, Trinodinae and Megatominae, and we dated the origins of all subfamilies between the Middle Jurassic and Upper Cretaceous. Extant genera started their diversification in the Middle Cretaceous, except for Dermestes that originated in the Eocene. Mycetophagy, the likely feeding style of the common ancestor with Endecatomidae, was retained only by Orphilinae. Since the Late Jurassic, most dermestids have been saprophagous with the preference for desiccated tissue. We infer a scenario of feeding preferences from mycetophagy moving to saprophagy, always depending on food with low water content, followed by the shift from cryptic life in crevices and wood, to commensalism with social Hymenoptera, and ultimately feeding on angiosperm pollen as adults. The dependence on spider larders evolved already in the Early Cretaceous, but lineages with this specialized strategy remained species‐poor. We date the origin of exploitation of vertebrate carcasses to the Eocene when modern mammalian fauna became dominant. The diversification of Megatominae (62% of known dermestids) and Attagenus Latreille (17%) coincides with the radiation of angiosperms.

Phylogenetic diversity of ferns reveals different patterns of niche conservatism and habitat filtering between epiphytic and terrestrial assemblages

Much attention has been directed to understanding species richness patterns, but adding an evolutionary perspective allows us to also consider the historical processes determining current diversity patterns. We analyzed phylogenetic patterns of fern species assemblages in 868 plots along a wide range of elevational (0-4000 m) and latitudinal (0°-23°N) gradients in the Neotropics to allow a deeper understanding of evolutionary processes underlying current patterns of diversity and community assembly. Overall, we found that phylogenetic mean pairwise distance (sMPD) and mean nearest taxon distance (sMNTD) decreased with increasing latitude and elevation, but that these geographical factors per se were weak explanatory variables. Incorporating environmental variables strongly enhanced the power of the predictive model, indicating that fern assemblages are phylogenetically more diverse under wet and warm to cool conditions at low latitudes and elevations. Further, whereas epiphytic fern assemblages were strongly influenced by climatic factors, this was not the case for terrestrial ones, suggesting that edaphic conditions and vegetation structure may have a stronger influence on the evolution and diversification of terrestrial ferns. We conclude that fern assemblages are strongly influenced by phylogenetic niche conservatism and environmental filtering. This has also been found for angiosperms, but the direction of the environment-phylogenetic relationship is often opposed in the two groups, suggesting that the older age of many fern lineages includes historical signals that are not evident in the more recent angiosperm radiation.

Patterns and drivers of phylogenetic structure of pteridophytes in China

AbstractAimPrevious studies have found strikingly different geographical patterns of phylogenetic diversity of gymnosperms and angiosperms, which have been suggested to result, in part, from the greater age of the former. To assess the effects of clade age on phylogenetic structure, we assessed phylodiversity patterns of pteridophytes (lycophytes and ferns), which combine ancient and modern lineages, across China.LocationChina.Time periodPresent day.TaxonPteridophytes.MethodsWe divided China into 66 regions and collated species lists of pteridophytes for each region. We then related taxonomic and phylogenetic diversity, and their related metrics, to six climatic variables for pteridophytes as a whole and for different evolutionary clades. We examined the effect of spatial autocorrelation among regional floras on the results.ResultsWe found that when all pteridophytes or ferns were considered, the patterns resembled those of gymnosperms, presumably reflecting the effects of several ancient global mass extinctions and the relict distribution of old families. In contrast, when we considered only the modern Polypodiales radiation, which accounts for three‐quarters of current fern diversity and is about as old as the angiosperm radiation, we found a pattern similar to that of angiosperms. This pattern is consistent with the tropical niche conservatism hypothesis and suggests that both major groups of land plants have a broadly similar evolutionary trajectory, with most families originating in tropical conditions and few families adapting to cold and arid conditions.Main conclusionsOur study shows that the phylogenetic structures of more recently evolved and diversified clades of pteridophytes are fairly consistent with the tropical niche conservatism hypothesis, suggesting that the age of the taxon, its physiological adaptations and the global climatic changes that it experienced during its evolutionary history are reflected in the composition of current plant assemblages.

Opsin Evolution in Flower-Visiting Beetles

Flowers have evolved signals that exploit the sensory systems of insect visitors. In the case of visual cues, color signals are thought to have been shaped in large part by the spectral sensitivity of key pollinators, such as hymenopterans. Beetles were some of the first plant pollinators, pre-dating the angiosperm radiation but with the exception of a few well-studied species, the evolution of flower-visiting beetle visual systems is poorly understood. Thus, the ability of beetles to detect and distinguish flower color signals and perhaps their potential role in shaping flower coloration is not well understood. Traditional models of pollinator visual systems often assume a putative tri- or tetrachromatic flower-visitor, as is found in bees, flies and butterflies. Beetles are unique among modern pollinators as ancestrally they did not possess the machinery for trichromatic vision, lacking the blue-sensitive photoreceptor class. Research on the evolution of visual genes responsible for wavelength sensitivity (opsins) has revealed that beetles with putative tri- and tetrachromatic visual systems have evolved independently, along multiple lineages. We explore the evolution of beetle visual genes using newly generated and publicly available RNA-seq data from 25 species with flower associations, including previously unexplored key flower-visitor groups and 20 non-flower visiting relatives. Our findings serve as a resource to inform and guide future studies on beetle-flower interactions, where insight from both signal and receiver is needed to better understand these poorly explored systems.

A previously missing link in the evolution of dasytine soft‐winged flower beetles from Cretaceous Charentese amber (Coleoptera, Melyridae)

AbstractThe soft‐winged flower beetles are a diverse cosmopolitan family of cleroid beetles with an unresolved higher classification, the adults of which feed on nectar and pollen. The fossil record of Melyridae is sparse, with only two described fossils known from the Mesozoic. Here we describe the first representative of the family from the Mesozoic of Europe, from early Cenomanian Charentese (French) amber. Due to the opaque nature of French amber, X‐ray microtomography was used to document fine morphological details of the fossil. Protodasytes cretaceus gen. et sp. nov. possesses a unique combination of characters within the subfamily Dasytinae, which is shared by the tribes Chaetomalachiini, Dasytini, and Listrini, namely the presence of a small antennal club, tarsomere 4 slightly shorter than 3 but not distinctly narrower, symmetrical claws, and a distinct pronotal and elytral fringe. This suggests that Dasytinae had begun to diversify by the Late Cretaceous, possibly in concert with the radiation of angiosperms. The fossil record of soft‐winged flower beetles is critically reviewed, and a checklist of extinct species is provided. The fragmentary Cenozoic fossils Troglops punctatissima and Malachius vertummni are removed from the family Melyridae, and the record of Attalus lusitanicus from Eocene–Oligocene Bembridge Marls is regarded as unlikely. The potential role of Protodasytes gen. nov. and Cretaceous melyrids as pollinators of early angiosperms is discussed.

The genome of Magnolia biondii Pamp. provides insights into the evolution of Magnoliales and biosynthesis of terpenoids

Magnolia biondii Pamp. (Magnoliaceae, magnoliids) is a phylogenetically, economically, and medicinally important ornamental tree species widely grown and cultivated in the north-temperate regions of China. Determining the genome sequence of M. biondii would help resolve the phylogenetic uncertainty of magnoliids and improve the understanding of individual trait evolution within the Magnolia genus. We assembled a chromosome-level reference genome of M. biondii using ~67, ~175, and ~154 Gb of raw DNA sequences generated via Pacific Biosciences single-molecule real-time sequencing, 10X Genomics Chromium, and Hi-C scaffolding strategies, respectively. The final genome assembly was ~2.22 Gb, with a contig N50 value of 269.11 kb and a BUSCO complete gene percentage of 91.90%. Approximately 89.17% of the genome was organized into 19 chromosomes, resulting in a scaffold N50 of 92.86 Mb. The genome contained 47,547 protein-coding genes, accounting for 23.47% of the genome length, whereas 66.48% of the genome length consisted of repetitive elements. We confirmed a WGD event that occurred very close to the time of the split between the Magnoliales and Laurales. Functional enrichment of the Magnolia-specific and expanded gene families highlighted genes involved in the biosynthesis of secondary metabolites, plant–pathogen interactions, and responses to stimuli, which may improve the ecological fitness and biological adaptability of the lineage. Phylogenomic analyses revealed a sister relationship of magnoliids and Chloranthaceae, which are sister to a clade comprising monocots and eudicots. The genome sequence of M. biondii could lead to trait improvement, germplasm conservation, and evolutionary studies on the rapid radiation of early angiosperms.

Subfamily Anischiinae (Coleoptera: Eucnemidae) in Early Cretaceous of Northeast China.

Simple SummaryA new false click-beetle (Eucnemidae) belonging to subfamily Anischiinae, formerly not known as fossils, extends the age of this small extant group 125 million years back. The structural specializations of the false click-beetle larvae are discussed. On the basis of this new piece of paleontological evidence, it is shown that these insects have changed their host preference from gymnosperms to angiosperms at least twice. It also indicates that the beetle larvae can switch their favored development substrate by adapting in different ways, either with or without morphological specialization.Rheanischia new genus, type species Rheanischia brevicornis new species (Eucnemidae, Anischiinae) is described from the Lower Cretaceous of Liaoning, China. The presence of this species in early Cretaceous deposits provides new insight into the evolution of basal lignicolous Eucnemidae clades. Both Anischiinae and Palaeoxeninae species diversified in a world dominated by gymnosperms, before the main radiation of angiosperms. More than 95% of modern eucnemid larvae have a Palaeoxenus-type highly modified head structure, but contrary to the Palaeoxenus larva, they develop in angiosperm wood. Anischiinae utilize angiosperms as well, but their head capsule shows no such modifications. These facts prove that highly specialized morphological features do not offer definite proof of similar way of life in the distant past, nor should non-modified structures be taken as proof for another kind of substrate choice. Eucnemidae have invaded angiosperms with two quite different morphological adaptations. This fact may have implications for the evolution of all clicking elateroids.

Evidence on vegetative and inflorescence morphology of Chloranthaceae (Angiospermae) from the Early Cretaceous (middle–late Albian) of Spain

The near-basal angiosperm family Chloranthaceae (with four living genera) is prominently represented in the Early Cretaceous fossil record by pollen and flowers, but its leaves, other vegetative parts and inflorescences are less well known. Here, we report impressions of leaves, stems and inflorescences from the middle–late Albian Escucha Formation of Teruel Province (NE Spain) that help redress this imbalance and bring into clearer focus the morphological and systematic diversity of this key group in the early angiosperm radiation. We used parsimony analysis of a morphological dataset of living and fossil Chloranthaceae to evaluate the position of the fossils on a molecular-based tree of extant taxa. Todziaphyllum elongatum gen. et sp. nov., with festooned semicraspedodromous venation and asymmetrical chloranthoid teeth, is most parsimoniously placed on the stem lineage of the living genus Hedyosmum. Leaves of Alcainea eklundiae gen. et sp. nov., with festooned semicraspedodromous venation and symmetric teeth, occur attached to stems in opposite pairs at swollen nodes with sheathing leaf bases and interpetiolar stipules, along with compound spikes of flowers with a monosymmetric androecium of three stamens, each flower subtended by a bract. This represents the first time that fossil leaves, stems and inflorescences of Chloranthaceae have been found in organic connection. Alcainea may be sister to Sarcandra, Chloranthus or the clade consisting of both genera, like the mesofossil Canrightiopsis. Leaf Type A, with festooned craspedodromous venation and symmetrical teeth, may be related to Ascarina. These observations provide direct evidence for the distinctive vegetative and inflorescence morphology of Chloranthaceae in the Early Cretaceous. They are consistent with the level of diversification inferred from coeval chloranthaceous pollen and floral mesofossils, including lines nested in crown group Chloranthaceae but not in any of living genera, and exhibiting character combinations not retained in living Chloranthaceae. http://zoobank.org/urn:lsid:zoobank.org:pub:08B96BA0-3B27-48A1-9E8F-CB5811AE8C07

Phylogenomics reveals accelerated late Cretaceous diversification of bee flies (Diptera: Bombyliidae).

Bombyliidae is a very species-rich and widespread family of parasitoid flies with more than 250 genera classified into 17 extant subfamilies. However, little is known about their evolutionary history or how their present-day diversity was shaped. Transcriptomes of 15 species and anchored hybrid enrichment (AHE) sequence captures of 86 species, representing 94 bee fly species and 14 subfamilies, were used to reconstruct the phylogeny of Bombyliidae. We integrated data from transcriptomes across each of the main lineages in our AHE tree to build a data set with more genes (550 loci versus 216 loci) and higher support levels. Our overall results show strong congruence with the current classification of the family, with 11 out of 14 included subfamilies recovered as monophyletic. Heterotropinae and Mythicomyiinae are successive sister groups to the remainder of the family. We examined the evolution of key morphological characters through our phylogenetic hypotheses and show that neither the "sand chamber subfamilies" nor the "Tomophthalmae" are monophyletic in our phylogenomic analyses. Based on our results, we reinstate two tribes at the subfamily level (Phthiriinae stat. rev. and Ecliminae stat. rev.) and we include the genus Sericosoma Macquart (previously incertae sedis) in the subfamily Oniromyiinae, bringing the total number of bee fly subfamilies to 19. Our dating analyses indicate a Jurassic origin of the family (165-194Ma), with the sand chamber evolving early in bee fly evolution, in the late Jurassic or mid-Cretaceous (100-165Ma). We hypothesize that the angiosperm radiation and the hothouse climate established during the late Cretaceous accelerated the diversification of bee flies, by providing an expanded range of resources for the parasitoid larvae and nectarivorous adults.

Food Reward Chemistry Explains a Novel Pollinator Shift and Vestigialization of Long Floral Spurs in an Orchid

During the evolutionary history of flowering plants, transitions between pollinator groups (pollinator shifts) have been frequent,1 and contributed to the spectacular radiation of angiosperms.2 Although the evolution of floral traits during pollinator shifts has been studied in real time under controlled laboratory conditions,3 it is challenging to study in nature and therefore poorly understood.4-7 Using a comparative, multidisciplinary approach, we dissect the evolution of floral traits during a pollinator shift in the long-spurred African orchid Satyrium longicauda. Phylogenetic analysis and ecological experiments revealed a shift from moth- to oil-collecting bee pollination. Remarkably, flowers of the bee-pollinated form are similar in morphology, color, and overall volatile chemistry to those of moth-pollinated forms, but differ in having spurs that are mostly devoid of nectar, and have an elevated presence of the oil-derived compound diacetin, which oil-collecting bees use as a cue for oil presence.8 Experiments demonstrated that long spurs are critical for pollination of a moth-pollinated form, but are not needed for pollination of the bee-pollinated form. We conclude that the pollinator shift in Satyrium was mediated by a switch in chemistry of the pollinator reward. The ancestral presence of diacetin might have served as a pre-adaptation for bee pollination, whereas the current mismatch between flower morphology and bees is due to the retention of vestigial floral spurs. These results elucidate the sequence of floral evolution in the early stages of pollinator shifts and help to explain the assembly of suites of co-varying traits through pre-adaptation and vestigialization.9-12.

Integrated phylogenomic and fossil evidence of stick and leaf insects (Phasmatodea) reveal a Permian-Triassic co-origination with insectivores.

Stick and leaf insects (Phasmatodea) are a distinctive insect order whose members are characterized by mimicking various plant tissues such as twigs, foliage and bark. Unfortunately, the phylogenetic relationships among phasmatodean subfamilies and the timescale of their evolution remain uncertain. Recent molecular clock analyses have suggested a Cretaceous–Palaeogene origin of crown Phasmatodea and a subsequent Cenozoic radiation, contrasting with fossil evidence. Here, we analysed transcriptomic data from a broad diversity of phasmatodeans and, combined with the assembly of a new suite of fossil calibrations, we elucidate the evolutionary history of stick and leaf insects. Our results differ from recent studies in the position of the leaf insects (Phylliinae), which are recovered as sister to a clade comprising Clitumninae, Lancerocercata, Lonchodinae, Necrosciinae and Xenophasmina. We recover a Permian to Triassic origin of crown Phasmatodea coinciding with the radiation of early insectivorous parareptiles, amphibians and synapsids. Aschiphasmatinae and Neophasmatodea diverged in the Jurassic–Early Cretaceous. A second spur in origination occurred in the Late Cretaceous, coinciding with the Cretaceous Terrestrial Revolution, and was probably driven by visual predators such as stem birds (Enantiornithes) and the radiation of angiosperms.

Higher‐level phylogeny of longhorn beetles (Coleoptera: Chrysomeloidea) inferred from mitochondrial genomes

AbstractCerambycidae (longhorn beetles) and related families in the superfamily Chrysomeloidea are important components of forest ecosystems and play a key role in nutrient cycling and pollination. Using full mitochondrial genomes and dense taxon sampling, the phylogeny of Chrysomeloidea with a focus on Cerambycidae and allied families was explored. We used 151 mitochondrial genomes (75 newly sequenced) covering all families and 29 subfamilies of Chrysomeloidea. Our results reveal that (i) Chrysomelidae (leaf beetles) are sister to all other chrysomeloid families; (ii) Cerambycidae sensu stricto (s. s.) is polyphyletic due to the inclusion of other families that split Cerambycidae into a ‘lamiine’ clade comprising Lepturinae sensu lato (s. l.) + (Lamiinae + Spondylidinae) and a ‘cerambycine’ clade comprising Dorcasominae + (Cerambycinae + Prioninae s. l.); (iii) the subfamilies within the two clades of Cerambycidae s. s. were monophyletic, except for the placement of Necydalinae nested in Lepturinae, and the placement of Parandrinae within Prioninae (now considered as tribes Necydalini and Parandrini, respectively); (iv) smaller families were grouped into two major clades: one composed of Disteniidae+Vesperidae and the other composed of Orsodacnidae + (Megalopodidae + Oxypeltidae); (v) relationships among the four major clades were poorly supported but were resolved as ((cerambycines + (Disteniidae + Vesperidae) + Orsodacnidae + (Megalopodidae + Oxypeltidae)) + lamiines. Divergence time analyses estimated that Chrysomeloidea originated ca. 154.1 Mya during the late Jurassic, and most subfamilies of Cerambycidae originated much earlier than subfamilies of Chrysomelidae. The diversification of families within Chrysomeloidea was largely coincident with the radiation of angiosperms during the Early Cretaceous.