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Premise of research. Myrcia s.l. is the largest exclusively Neotropical genus of Myrtaceae, comprising about 800 species. This large genus is divided into 10 clades, most of these recently publishe...

Made available in DSpace on 2022-04-28T19:44:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-09-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Aim: Ancient climatic fluctuations are invoked as the main driving force that generates the astonishing biodiversity in ancient mountains. As a result, endemism and spatial turnover are usually high and few species are widespread amongst entire mountain ranges, precluding the understanding of origins of macroevolutionary patterns. Here, we used a species endemic to, but widespread in, one of the most species-rich ancient mountains in the globe to test how environmental changes acted on and how their macroevolutionary patterns were shaped. Location: Espinhaço Range, Eastern Brazil. Taxon: Vriesea oligantha species complex (Bromeliaceae). Methods: We compiled data for plastidial regions and nuclear microsatellites to assess genetic diversity, population structure, migration rates and phylogenetic relationships. Using temperature and precipitation variables, we modelled suitable areas for the present and the past, estimating corridors between isolated populations. We also implemented Bayesian demographic analyses to estimate ancient populations dynamics. Finally, we tested if population structure is driven by isolation by environment or by distance using a Bayesian modelling approach. Results: Our results showed that the intraspecific divergence events of V. oligantha are older than those associated with the latest Pleistocene climatic oscillations, supporting the view that Quaternary climatic fluctuations are key components for understanding its population differentiation processes. Species distribution modelling estimated corridors between populations in the past, as also shown in the demographic analyses, depicting a major spatial reorganization during colder climates. Besides, the high genetic structure estimated results from both models of isolation by distance and by environment. Main conclusions: V. oligantha is a remarkable model to test the effects of climatic oscillations over the biological community, since this species originated in the early-Pleistocene, prevailing over several cycles of climatic fluctuations until today. The estimated demographic dynamics of V. oligantha agrees with the species-pump mechanism, suggesting it as the main cause of speciation within the Espinhaço Range. Moreover, the phylogeographic patterns of V. oligantha reflect previously recognised spatial and temporal macroevolutionary patterns in the Espinhaço Range, providing insights into how microevolutionary processes may have given rise to this astonishing mountain biodiversity. Programa de Pós-graduação em Biologia Vegetal Universidade Estadual Paulista (UNESP) Departamento de Biologia Vegetal Instituto de Biologia Universidade Estadual de Campinas (UNICAMP) Department of Biological Sciences University of Arkansas Departamento de Botânica e Zoologia Centro de Biociências Universidade Federal do Rio Grande do Norte (UFRN) Programa de Pós-graduação em Biologia Vegetal Universidade Estadual Paulista (UNESP) CNPq: 303794/2019-4 LMV CNPq: 305398/2019-9 CPS CAPES: 88881.128215/2016-01 MVDQ CAPES: PDSE 88881.190071/2018-01 MVDQ CAPES: PROAP-2015/CAPES/PPGCB-BV CNPq: produtividade 300819/2016-1 CNPq: produtividade 304778/2013-3

Phylogenetic studies have highlighted incongruous generic placement and the usage of inappropriate names for species within tribe Myrteae (Myrtaceae). The genera affected are Calycolpus, Eugenia, Myrcia and Psidium. Eugenia aubletiana is legitimized by the designation of a lectotype and its usage proposed instead of Calycorectes bergii. Two generic transfers are proposed: Psidium sessiliflorum based on Calycolpus sessiliflorus and Myrcia neosericea, based on Eugenia neosericea. The re-instatement of Psidium cupreum, currently a synonym of Psidium rufum as an accepted species is proposed. Illustrations of the four affected species are furnished, as well as a map of occurrences of Psidium sessiliflorum. Tetramery associated to inflorescences reduced to 1(-3) flowers, an unusual combination of characters in Myrcia sect. Gomidesia, is identified in both Myrcia glaziovii and Myrcia neosericea, and a key to distinguish them is provided.

In science, standardization of terminology is crucial to make information accessible and allow proper comparison of studies’ results. Climbing plants and the climbing habit have been described in numerous ways, frequently with imprecise and dubious terms. We propose a standardization of terms regarding the climbing habit, with special attention to climbing mechanisms. We abide by previous suggestions that the terms “primary” and “secondary” hemiepiphyte be substituted by “hemiepiphyte” and “nomadic climber” respectively, thus emphasizing the relationship of the latter to the climbing habit. We also suggest that “climbing plant” or “climber” be used to describe plants displaying the climbing habit, and “liana” and “vine” be left for describing woody and herbaceous climbers respectively. As for climbing mechanisms, we propose an eight-category classification comprised of two major categories: passive climbing, containing scrambling, hooks or grapnels, and adhesive roots; and active climbing, containing twining, tendrils, prehensile branches, twining petioles, and twining inflorescences.

Myrcia lucasae (Myrcia sect. Gomidesia, Myrtaceae), a new species from the Bahia state, Brazil, is here described and illustrated. It differs from M. lughadhae, a closely related and sympatric species, by the strigose indumentum with ferruginous trichomes and the absence of ribs on fruits. It is also different and from M. virgata (Myrcia sect. Myrcia), by presenting thecae with irregular dorsal openings (characteristics of Myrcia sect. Gomidesia). Collections of M. lucasae have been constantly misidentified as the morphologically similar M. virgata, a species from a different section, which does not occur in the state of Bahia. Myrcia lucasae is endemic to the highly diverse campo rupestre vegetation of the Chapada Diamantina biogeographic province. We also provide preliminary conservation assessment, comments on distribution and ecological aspects of this new taxon.

Mountains are among the most biodiverse areas on the globe. In young mountain ranges, exceptional plant species richness is often associated with recent and rapid radiations linked to the mountain uplift itself. In ancient mountains, however, orogeny vastly precedes the evolution of vascular plants, so species richness has been explained by species accumulation during long periods of low extinction rates. Here we evaluate these assumptions by analysing plant diversification dynamics in thecampo rupestre, an ecosystem associated with pre-Cambrian mountaintops and highlands of eastern South America, areas where plant species richness and endemism are among the highest in the world. Analyses of 15 angiosperm clades show that radiations of endemics exhibit fastest rates of diversification during the last 5 Myr, a climatically unstable period. However, results from ancestral range estimations using different models disagree on the age of the earliestin situspeciation events and point to a complex floristic assembly. There is a general trend for higher diversification rates associated with these areas, but endemism may also increase or reduce extinction rates, depending on the group. Montane habitats, regardless of their geological age, may lead to boosts in speciation rates by accelerating population isolation in archipelago-like systems, circumstances that can also result in higher extinction rates and fast species turnover, misleading the age estimates of endemic lineages.

International audience; Premise To further advance the understanding of the species-rich, economically and ecologically important angiosperm order Myrtales in the rosid clade, comprising nine families, approximately 400 genera and almost 14,000 species occurring on all continents (except Antarctica), we tested the Angiosperms353 probe kit. Methods We combined high-throughput sequencing and target enrichment with the Angiosperms353 probe kit to evaluate a sample of 485 species across 305 genera (76% of all genera in the order). Results Results provide the most comprehensive phylogenetic hypothesis for the order to date. Relationships at all ranks, such as the relationship of the early-diverging families, often reflect previous studies, but gene conflict is evident, and relationships previously found to be uncertain often remain so. Technical considerations for processing HTS data are also discussed. Conclusions High-throughput sequencing and the Angiosperms353 probe kit are powerful tools for phylogenomic analysis, but better understanding of the genetic data available is required to identify genes and gene trees that account for likely incomplete lineage sorting and/or hybridization events.

Shedding a fused perianth as a calyptra at anthesis is a trait that has evolved independently multiple times in angiosperm evolutionary history. However, calyptras do not correspond to homologous structures in all cases. Here, we describe calyptra development in the evolutionary context of Myrtaceae tribe Syzygieae. We use scanning electron and light microscopy to contrast calyptra development in calyptrate and non-calyptrate species in the group. Results show that calyptras in Syzygieae are not all homologous, but correspond to two ontogenetically distinct structures involving different perianth whorls that resemble each other by convergence: a calycine structure, in which the sepals are fused; and a pseudocalyptra, in which petals fall as a single unit but are not fused. Presence of non-calyptrate flowers is the ancestral state in the tribe, and both calyptra types appeared multiple times in the evolution of the group, with infrequent reversals from the calyptrate to the non-calyptrate state. Results highlight the fact that similar terminology in non-homologous structures can affect even relatively restricted lineages. The recurrent evolution of the calyptra in Syzygieae, with little evidence for reversal, shows that these structures may be advantageous in certain conditions but also correspond to an evolutionary dead-end in the group.

—With ca. 2500 species, Myrteae is the largest tribe of Myrtaceae and one of the most diverse groups of flowering plants in the tropical Americas. In light of recent systematics adjustments, the present study is a review and provides new insights into floral diversity and evolution in Myrteae. General aspects of floral ontogeny and morphology for the fifty currently accepted genera plus all accepted sections within the large genera Eugenia and Myrcia are summarized based on current morphological data. The discussion provides a broader understanding of the floral diversity across the tribe, highlighting developmental modes, ecological traits, and specializations in reproductive strategies. Hypotheses to be tested in future studies are also presented and discussed.

—A new classification of the predominantly Neotropical tribe Myrteae is proposed to replace Berg’s three traditional subtribes, the Myrciinae, Eugeniinae, and Myrtinae. Nine subtribes are here proposed that are supported by molecular and morphological data. In addition to the three traditionally recognized but modified here, subtribe Pimentinae (originally described as Pimentoideae) is reinstated and five new subtribes are proposed: Blepharocalycinae, Decasperminae, Luminae, Pliniinae, and Ugninae. A key to the nine subtribes is followed by descriptions of each, listing genera included, approximate species numbers, general distribution patterns, and notes. The genera Feijoa O. Berg and Temu O. Berg are reinstated. Morphological structures of importance for classification of Myrteae subtribes are illustrated.

AIM: The Brazilian campo rupestre is a vegetation associated to ancient mountaintops in eastern South America, spread mainly over disjunct areas of the Espinhaco Range and the Chapada dos Veadeiros. These areas hold outstanding levels of plant diversity and endemism, but despite their uniqueness they have been neglected in recent bioregionalizations for the Neotropical region. Given their particular levels of species richness and endemism, we here test the recognition of these as distinct bioregions within the Chacoan dominion. LOCATION: Mountaintops of eastern South America. METHODS: We listed 1,748 angiosperm species endemic to the campo rupestre of the Espinhaco Range and Chapada dos Veadeiros regions, based on the data gathered from the Brazilian Flora 2020 Project. We extracted all occurrence information available from GBIF (the Global Biodiversity Information Facility) for such list and also for a polygon gathering all the study area, including information from adjacent vegetations. Data went through standard cleaning procedures and a network clustering analysis was performed to delimitate the boundaries of the new bioregions. RESULTS: Our data strongly support the recognition of two distinct bioregions along the Espinhaco Range, but none in the Chapada dos Veadeiros. Given their high levels of endemism and singularity within the Chacoan dominion, we formalize two provinces associated to campo rupestre in the Espinhaco Range, naming them as “Chapada Diamantina” and “Southern Espinhaco” provinces. Within the latter province, three districts are also recognized, based on this and previous studies: “Diamantina Plateau”, “Grao‐Mogol” and “Iron Quadrangle” districts. MAIN CONCLUSIONS: The formalization of new and previously described bioregions highlights the campo rupestre as a vegetation harbouring outstanding levels of species richness and endemism in South America, contributing to a better understanding of biogeographical patterns in the Neotropics. Also, as we follow the International Code of Area Nomenclature as a device to standardize recognition of bioregions, this shall facilitate further biogeographical and conservation studies in these areas. Further assessments with new and revisited data are needed to enable minor scale bioregionalization within the Chacoan dominion.

The value of natural history collections for conservation science research is increasingly recognized, despite their well‐documented limitations in terms of taxonomic, geographic, and temporal coverage. Specimen‐based analyses are particularly important for tropical plant groups for which field observations are scarce and potentially unreliable due to high levels of diversity‐amplifying identification challenges. Specimen databases curated by specialists are rich sources of authoritatively identified, georeferenced occurrence data, and such data are urgently needed for large genera. We compared entries in a monographic database for the large Neotropical genus Myrcia in 2007 and 2017. We classified and quantified differences in specimen records over this decade and determined the potential impact of these changes on conservation assessments. We distinguished misidentifications from changes due to taxonomic remodeling and considered the effects of adding specimens and georeferences. We calculated the potential impact of each change on estimates of extent of occurrence (EOO), the most frequently used metric in extinction‐risk assessments of tropical plants. We examined whether particular specimen changes were associated with species for which changes in EOO over the decade were large enough to change their conservation category. Corrections to specimens previously misidentified or lacking georeferences were overrepresented in such species, whereas changes associated with taxonomic remodeling (lumping and splitting) were underrepresented. Among species present in both years, transitions to less threatened status outnumbered those to more threatened (8% vs 3%, respectively). Species previously deemed data deficient transitioned to threatened status more often than to not threatened (10% vs 7%, respectively). Conservation scientists risk reaching unreliable conclusions if they use specimen databases that are not actively curated to reflect changing knowledge., Article impact statement: Digitized natural history collections must be updated as taxonomic knowledge grows so as to maximize their utility for conservation science.

Premise of research. The opening of the Drake Passage in the Miocene (disconnecting Antarctica and South America and resulting in the establishment of the Circumpolar Current preventing warm waters...

Glaziou was one of the most prominent plant collectors in the history of Brazilian botany. His field expeditions during the second Cruls Mission (1894–1895) in the area now recognized as Goiás and Distrito Federal led him to collect 26 of the 32 species of Myrcia he was to name in his botanical career. Glaziou´s itinerary in the second Cruls Mission was reconstructed and mapped, showing he spent 40% of his collecting days in the present Distrito Federal and 60% in Goiás. His List of Species is now considered a suppressed work by the International Code of Nomenclature for the Algae, Fungi and Plants because he did not fulfill the criteria for formal species description. After examining over 300 specimens in Brazilian and European herbaria, we concluded that 23 of his names are synonyms of older, currently accepted names. The remaining three names are new species and are here formally described. This work underlines the importance of revisiting historical collections following recent changes in Myrcia taxonomy, to improve the understanding of species diversity in ecologically heterogeneous areas in large, morphologically complex genera such as Myrcia.

Made available in DSpace on 2021-06-26T07:27:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-21 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) FApdf Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Premise There is little direct evidence linking floral development and pollination biology in plants. We characterize both aspects in plain and ornamented flowers of Trimezieae (Iridaceae) to investigate how changes in floral ontogeny may affect their interactions with pollinators through time. Methods We examined floral ontogeny in 11 species and documented pollination biology in five species displaying a wide range of floral morphologies. We coded and reconstructed ancestral states of flower types over the tribal phylogeny to estimate the frequency of transition between different floral types. Results All Trimezieae flowers are similar in early floral development, but ornamented flowers have additional ontogenetic steps compared with plain flowers, indicating heterochrony. Ornamented flowers have a hinge pollination mechanism (newly described here) and attract more pollinator guilds, while plain flowers offer less variety of resources for a shorter time. Although the ornamented condition is plesiomorphic in this clade, shifts to plain flowers have occurred frequently and abruptly during the past 5 million years, with some subsequent reversals. Conclusions Heterochrony has resulted in labile morphological changes during flower evolution in Trimezieae. Counterintuitively, species with plain flowers, which are endemic to the campo rupestre, are derived within the tribe and show a higher specialization than the ornamented species, with the former being visited by pollen-collecting bees only. Univ Fed Paraiba, Dept Sistemat & Ecol, Caixa Postal 5065,Cidade Univ, BR-58051970 Joao Pessoa, Paraiba, Brazil Univ Sao Paulo, Dept Bot, Rua Matao 277, BR-05508090 Sao Paulo, SP, Brazil Univ Fed Santa Catarina, Dept Bot, Campus Trindade, BR-88040900 Florianopolis, SC, Brazil Univ Arkansas, Dept Biol Sci, Fayetteville, AR 72701 USA Univ Estadual Paulista, Ave 24A, BR-13506900 Rio Claro, SP, Brazil Royal Bot Gardens, Richmond TW9 3DS, Surrey, England Univ Brasilia, Dept Zool, BR-70910900 Brasilia, DF, Brazil Univ Estadual Paulista, Ave 24A, BR-13506900 Rio Claro, SP, Brazil CNPq: 455558/2014-0 FAPESP: 2014/09131-3 FAPESP: 2012/18396-5 FAPESP: 2014/00803-9 FAPESP: 2018/02191-1 CNPq: 303786/2010-8 FApdf: 0193.000.893/2015

Additional information and results from biogeographical analyses.

Description of methods used in phylogenetic tree inference and calibration.

Additional information and results from diversification analyses.

A short literature review describing the reasoning behind choosing the sample of clades used in the analyses.

Background and Aims Comparative floral ontogeny represents a valuable tool to understand angiosperm evolution. Such an approach may elucidate subtle changes in development that discretely modify floral architecture and underlie reproductive lability in groups with superficial homogeneous morphology. This study presents a comparative survey of floral development in Eugenia (Myrtaceae), one of the largest genera of angiosperms, and shows how previously undocumented ontogenetic trends help to explain the evolution of its megadiversity in contrast to its apparent flower uniformity. Methods Using scanning electron microscopy, selected steps of the floral ontogeny of a model species (Eugenia punicifolia) are described and compared with 20 further species representing all ten major clades in the Eugenia phylogenetic tree. Additional floral trait data are contrasted for correlation analysis and character reconstructions performed against the Myrtaceae phylogenetic tree. Key results Eugenia flowers show similar organ arrangement patterns: radially symmetrical, (most commonly) tetramerous flowers with variable numbers of stamens and ovules. Despite a similar general organization, heterochrony is evident from size differences between tissues and structures at similar developmental stages. These differences underlie variable levels of investment in protection, subtle modifications to symmetry, herkogamic effects and independent androecium and gynoecium variation, producing a wide spectrum of floral display and contributing to fluctuations in fitness. During Eugenia's bud development, the hypanthium (as defined here) is completely covered by stamen primordia, unusual in other Myrtaceae. This is the likely plesiomorphic state for Myrteae and may have represented a key evolutionary novelty in the tribe. Conclusions Floral evolution in Eugenia depends on heterochronic patterns rather than changes in complexity to promote flexibility in floral strategies. The successful early establishment of Myrteae, previously mainly linked to the key innovation of fleshy fruit, may also have benefitted from changes in flower structure.

The greatest challenge to the modern plant systematist is the interpretation of molecular phylogenies that do not correspond to previous classifications based on morphological data. Characters that on first appearance seem highly diagnostic are brought into focus by phylogeny and frequently shown to have evolved multiple times independently. Parallelism is usually neglected in such systematic studies and the homoplastic distribution of a character in a phylogeny is commonly accredited to convergent evolution. The impact of parallel evolution on angiosperm systematics is examined here using a taxonomically complex and species-rich group of tropical tree genera ( Myrcia , Marlierea, Calyptranthes ; Myrtaceae) as a case study. These groups are traditionally distinguished by flower characters and have been shown to be polyphyletic by molecular data. Floral ontogeny of distinct lineages is examined using SEM and plotted on a five gene phylogenetic hypothesis to estimate ancestral states and phylogenetic signal for developmental variation. Results show that floral characters responsible for taxonomic confusion are a result of both parallel evolution and convergence. This is contrasted with other diverse and taxonomically complex angiosperm groups and problematic taxonomy appears linked to recent diversification events where the same genetic basis remains latent, demonstrating parallelism to be an important factor in problematic taxonomies. In this study, variations in early stage floral development produce the most labile characters. This is discussed in light of ontogenetic patterns in angiosperms with focus on the evolutionary consequences of homoplastic variation during early vs late floral development. The prevalence of parallelism must be appreciated by taxonomists of complex groups. Future classifications of groups affected by parallelism are likely to require data from detailed, multi-disciplinary studies of key characters to interpret phylogenies correctly.

Species of plants with different life history strategies may differ in their seed dispersal mechanisms, impacting their distribution and diversification patterns. Shorter or longer distance dispersal is favored by different dispersal modes, facilitating (or constraining) population isolation, which can, in turn, impact speciation and species range sizes. While these associations are intuitive, few studies have explicitly tested these hypotheses for large clades of angiosperms. The plant family Melastomataceae is found on disparate habitats with different dispersal modes, representing a good model to address these questions. In this study, we reconstruct the phylogeny of Melastomataceae and gather data on their dispersal mode and range size to test the impact of dispersal mode on diversification and range size evolution. We found that abiotic dispersal is ancestral in the family, while biotic dispersal evolved multiple times. Species richness distribution is very similar across dispersal modes, although abiotically dispersed species tend to be relatively more diverse in seasonal environments. Range sizes across dispersal modes are not significantly different, although biotically dispersed species have slightly wider distributions. Model comparisons indicate that factors other than dispersal mode might have driven diversification heterogeneity. We did not find evidence for the role of dispersal mode driving diversification rates or range size in the Melastomataceae, suggesting a complex macroevolutionary scenario for this diverse angiosperm family. The bulk of changes to biotic dispersal coinciding with an increase in passerine diversification suggests a possible “past” key innovation in Melastomataceae. Future studies should investigate the role of other diversification drivers in the family and the relatively higher diversity of abiotically dispersed species in open habitats.

Worldwide distributed tropical savannas were established only in the Miocene, with climatic cooling and rise of C4 grasses. However, there is evidence for an earlier presence of savanna-like vegetation in southern parts of South America. Here we investigated the biogeographic history of a clade of solitary bees which have endemic groups in areas covered by savannas and other types of open vegetation as well as forested areas. We hypothesized that these bees originated in savanna-like biomes and that shifts to forested areas and floral host shifts increased species diversification along their evolutionary history. We reconstructed a comprehensive phylogeny for Tapinotaspidini bees based majorly on original DNA sequences. We then used macroevolutionary tools to estimate ancestral range area and reconstructed ancestral habitat (open versus forested) and host plant association to analyze the effects of shifts in vegetation type and flower hosts on their diversification. Tapinotaspidini bees originated in the Paleocene and in a savanna-type, Cerrado-like, which is reinforced by reconstruction of open vegetation as the most probable ancestral area, thus bringing additional evidence to a much earlier origin of this vegetation type in South America. Shifts to forested areas occurred at least three times in a period of 30 Ma and were responsible for slight increases in diversification rates. Malpighiaceae is the ancestral floral host; host broadening occurred only in the Miocene and at least in three occasions. Host shifts, i.e. from Malpighiaceae to other oil families, occurred in the Eocene and Miocene. Both host broadening and host shifts did not significantly alter diversification rates, however exploitation of other oil sources were important in occupying new habitats. The link between biomes and host plant shifts and changes in diversification rate brings us additional insights into the evolution of bees and associated flora in South America.

Eugenia has a pantropical distribution and comprises ca. 1000 species found mostly in the Neotropics. Recent DNA based phylogenies show that unusual flower morphology of 'eugenioid' collections, e.g. fused calices that open by tearing, consistently emerged within Eugenia. These results emphasize a demand to revaluate flower morphology in a phylogenetic context within the genus. A reassessment of calyx fusion in Eugenia and traditionally related genera is here focused on clarification of the systematic relevance of this apparently recurrent characteristic. Twenty-four Eugenia species with some level of calyx fusion in the bud were newly used (one nuclear and four plastid markers) in conjunction with a representative sample of previously sequenced species to recover a time-calibrated Eugenia phylogeny of 86 accessions. Development of the fused calyx was analysed using scanning electron microscopy, differing patterns were re-coded and subsequently phylogenetic character reconstruction was performed. Eugenia was recovered as monophyletic including the traditionally segregated genera Calycorectes and Catinga. Ancestral character reconstruction uncovered free calyx lobes as the ancestral condition. Five development patterns leading to calyx fusion are reported in Eugenia including species with apparently six petals, which contrast with the standard tetramerous flowers. This condition is interpreted as the petaloid pattern, where two external fused calyx lobes cover the bud while two internal calyx lobes are free and petaloid. The fused calyx condition is homoplastic and evolved independently, several times in Eugenia, as did the different development patterns. Data presented here show that systematic incongruence resulting from multiple, independent origins of the fused calyx in Eugenia is further aggravated by an inability to distinguish parallelism and convergence within the recovered patterns.

Changes in floral traits across evolutionary time are expected in response to selective pressures imposed by pollinators. Stamen dimetrism (here defined as size differences between stamens within the same flower) represents an important strategy to decrease pollen loss during bee-flower interactions in pollen flowers. However, the evolutionary history of stamen dimetrism, and the links between this and other reproductive traits across long periods of time are still poorly understood. Here we investigate the evolution of stamens dimetrism and the evolutionary correlation of this trait and other floral structures and reproductive strategies in Melastomataceae. Floral traits were scored from 336 species and reproductive biology data was gathered for 81 species. Stamen dimetrism is a labile trait, appeared several times throughout the evolutionary history of this clade and is evolutionarily correlated to floral size. Among the 81 species analyzed, we observed that the lineages that depend on pollinators to reproduce correspond to those that evolved the highest stamen dimetrism. The evolutionary lability of stamen dimetrism has probably contributed to the maintenance of the buzz pollination adaptive plateau in possibly the largest radiation of pollen flowers in angiosperms.

Myrcia is the largest exclusively Neotropical genus of the plant family Myrtaceae with c. 770 species. Although several studies have elucidated the relationships within particular sections of the genus, to date no phylogeny has been produced that includes a broad taxonomic and geographic representation. Here we present a phylogenetic hypothesis of Myrcia and close relatives comprising 253 species and based on two nuclear and seven plastid markers. We combine previously available sequence data with 234 new sequences of the genus Myrcia for this study. We use this phylogeny to investigate the evolution of selected morphological traits and to infer the biogeographic history of the genus. Our results yield a highly supported phylogenetic tree where the Myrceugenia group is sister to the Myrcia and Plinia groups. Five Myrcia species previously considered unplaced emerge in a newly circumscribed clade. The monophyly of two Myrcia sections previously considered uncertain, Aulomyrcia and Gomidesia, are confirmed with strong support. Flowers with free calyx lobes, 2-locular ovaries, and anthers with symmetrical thecae are ancestral features of Myrcia. The Myrcia sect. Gomidesia is highly supported and recovered as monophyletic, with asymmetric anthers that retain their curvature after dehiscence as a morphological synapomorphy. The Atlantic Forest is the most likely ancestral area of the genus and most of its internal clades, from where multiple lineages colonized different regions of South and Central America, in particular the Brazilian Cerrado through multiple unidirectional range expansions. The southern Atlantic Forest is the ancestral area for Myrcia sect. Gomidesia, with lineages reaching the northern Atlantic Forest, Cerrado, Yungas, and other savanna vegetation of South America. Our results provide a solid backbone for further evolutionary and taxonomic work and clarify several previously uncertain relationships in this mega-diverse plant group, and shed light on its geographical range evolution.

Changes in floral morphology are expected across evolutionary time and are often promoted as important drivers in angiosperm diversification. Such a statement, however, is in contrast to empirical observations of species-rich lineages that show apparent conservative floral morphologies even under strong selective pressure to change from their environments. Here, we provide quantitative evidence for prolific speciation despite uniform floral morphology in a tropical species-rich tree lineage. We analyse floral disparity in the environmental and phylogenetic context of Myrcia (Myrtaceae), one of the most diverse and abundant tree genera in Neotropical biomes. Variation in floral morphology among Myrcia clades is exceptionally low, even among distantly related species. Discrete floral specialisations do occur, but these are few, present low phylogenetic signal, have no strong correlation with abiotic factors, and do not affect overall macroevolutionary dynamics in the lineage. Results show that floral form and function may be conserved over large evolutionary time scales even in environments full of opportunities for ecological interactions and niche specialisation. Species accumulation in diverse lineages with uniform flowers apparently does not result from shifts in pollination strategies, but from speciation mechanisms that involve other, nonfloral plant traits.

Made available in DSpace on 2018-11-26T16:01:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-04-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) A new classification of the large Neotropical genus Myrcia s.l. is proposed. Nine sections are presented that correspond to recently published clades. Of these nine sections, sects. Myrcia, Aulomyrcia and Sympodiomyrcia are already published, sects. Reticulosae and Tomentosae are new sections, sect. Eugeniopsis is a new combination whilst sects. Aguava, Calyptranthes and Gomidesia are new combinations at a new rank (comb. & stat. nov.). Six lectotypifications are made for sections or genera. Estimates of species per section are listed. Royal Bot Gardens, Richmond, Surrey, England Univ Estado Amazonas, BR-69058807 Manaus, Amazonas, Brazil Univ Estadual Campinas, Campinas, SP, Brazil Univ Brasilia, Brasilia, DF, Brazil Jardim Bot Brasilia, Brasilia, DF, Brazil Univ Estado Para, Belem, Para, Brazil Univ Fed Rural Pernambuco, Recife, PE, Brazil Univ Fed Sao Carlos, Sao Paulo, Brazil Univ Fed Rural Rio de Janeiro, Rio De Janeiro, Brazil Univ Estadual Paulista, Rio Claro, Brazil Univ Fed Sao Joao Del Rei, Sao Joao Del Rei, MG, Brazil Univ Estadual Paulista, Rio Claro, Brazil CNPq: 150217/2016-1 CNPq: 205237/2014-2 CNPq: 165669/2013-6

The taxonomy of Myrteae, the most species-rich tribe of Myrtaceae, is notoriously difficult. Although the understanding of the phylogeny has improved, the morphological characteristics that support its cladistic configuration are still unknown. The present study evaluates stamen position and anthesis type as characters of systematic and evolutionary relevance. Sixty-nine species from 41 genera across the tribe were checked using herbarium material and spirit collections. The results recognize three patterns of stamen position in the pre-anthetic bud: straight, semi-curved and strongly incurved. The three patterns of stamen position correspond to the phylogenetic structure of the tribe, supporting the topology of the clades. Incurving of stamens across the evolutionary history of Myrteae appears to be linked to hypanthium extension and leads to different anthesis types that may be related to shifts in pollination strategy. The accessibility of stamen position and its systematic consistency make this character a useful tool for field and herbarium identification, and allow the inference of relationships for taxa not yet sampled in molecular analyses. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179, 388–402.

PREMISE OF THE STUDY Floral display describes the effect of flower size combined with the number of flowers per inflorescence. There is strong evidence that a floral-display trade-off operates under energetic constraint, with few-flowered inflorescences likely to have larger flowers than many-flowered inflorescences. Flower size can be estimated by different variables; thus, we propose that the variable for flower size that is most highly (negatively) correlated with the number of flowers per inflorescence will also be the best estimate of floral cost. Ranking the correlation with the phylogenetic signal of the variable can provide additional insight into the evolution of floral display. METHODS The Myrtales were chosen as a model order based on age, worldwide distribution, and diversity of reproductive strategies. Ninety-nine species representing all families and one quarter of generic diversity across its geographic and ecological range were sampled to reconstruct a phylogeny based on rbcL and ndhF sequences. Correlation coefficients were calculated for flower size variables vs. the number of flowers per inflorescence. Phylogenetic signal was measured for all variables and for floral display. KEY RESULTS Flowers per inflorescence showed significant negative correlation with the following flower size variables (weakest to strongest): filament length < anther size < flower depth < flower diameter. As the correlation of each character with number of flowers per inflorescence rose (suggesting increased cost), the values for phylogenetic signal diminished (suggesting less constraint). CONCLUSIONS We conclude that energetically costly floral characters appear to be less phylogenetically constrained, while low-cost floral characters maintain higher levels of phylogenetic inertia.

Myrteae (c. 2500 species; 51 genera) is the largest tribe of Myrtaceae and an ecologically important groups of angiosperms in the Neotropics. Systematic relationships in Myrteae are complex, hindering conservation initiatives and jeopardizing evolutionary modelling. A well-supported and robust phylogenetic hypothesis was here targeted towards a comprehensive understanding of the relationships within the tribe. The resultant topology was used as a base for key evolutionary analyses such as age estimation, historical biogeography and diversification rate patterns. One nuclear (ITS) and seven chloroplast (psbA-trnH, matK, ndhF, trnl-trnF, trnQ-rps16, rpl16 and rpl32-trnL) DNA regions for 115 taxa representing 46 out of the 51 genera in the tribe were accessed and analysed using maximum likelihood and Bayesian inference tools for phylogenetic reconstruction. Dates of diversification events were estimated and contrasted using two distinct fossil sets (macro and pollen) in BEAST. The subsequent dated phylogenies were compared and analysed for biogeographical patterns using BioGeoBEARS and diversification rates using BAMM. Myrteae phylogeny presents strong statistical support for three major clades within the tribe: Australasian group, Myrtus group and Main Neotropical Lineage. Dating results from calibration using macrofossil are an average of 20 million years older and show an early Paleocene origin of Myrteae, against a mid-Eocene one from the pollen fossil calibration. Biogeographic analysis shows the origin of Myrteae in Zealandia in both calibration approaches, followed by a widespread distribution throughout the still-linked Gondwana continents and diversification of Neotropical endemic lineages by later vicariance. Best configuration shift indicates three points of acceleration in diversification rates, all of them occurring in the Main Neotropical Lineage. Based on the reconstructed topology, several new taxonomic placements were recovered, including: the relative position of Myrtus communis, the placement of the Blepharocalyx group, the absence of generic endemism in the Caribbean, and the paraphyletism of the former Pimenta group. Distinct calibration approaches affect biogeography interpretation, increasing the number of necessary long distance dispersal events in the topology with older nodes. It is hypothesised that biological intrinsic factors such as modifications of embryo type and polyploidy might have played a role in accelerating shifts of diversification rates in Neotropical lineages. Future perspectives include formal subtribal classification, standardization of fossil calibration approaches and better links between diversification shifts and trait evolution.