Wild and cultivated comestible plant species in the Gulf of Mexico: phylogenetic patterns and convergence of type of use.

Cross-cultural research on edible plants might include ecological and evolutionary perspectives to understand processes behind species selection and management. With a database of approximately 500 comestible plants of the Province of the Gulf of Mexico in Mesoamerica, phylogenetic analyses are conducted to identify convergence and phylogenetic signal of type of use and significant clustering in the resulting phylogenetic trees. Analyses considered type of management (wild/managed vs. cultivated), type of use (edible, condiment, for wrapping food) and organ utilized. Elevated phylogenetic diversity and signal are expected for wild comestible taxa, indicating that people are using lineages across the angiosperm tree for food, resulting in broadness in diet and use of their regional resources. Main results are: (i) condiment species were identified in groups with an elevated phylogenetic signal; (ii) hot nodes for lineages utilized for wrapping food were found in many monocot groups as well as in epiphytes of cloud forests with leathery leaves; (iii) edible taxa were identified with the highest significant clustering restricted to certain branches in the phylogeny; (iv) wild and cultivated edible plants belong to identical lineages with replacement of species, implying that same plant groups known for their comestible benefits are substituted by species distributed in the Province and (v) wild versus cultivated lineages for condiment are different. Most food species in the Province belong to four families, namely Fabaceae, Cactaceae, Solanaceae and Asparagaceae. Analyses discovered underutilized wild species in identical clades to managed/cultivated taxa that can be studied further to identify cultivation practices. Results suggest that people are utilizing different lineages in the angiosperm tree available locally, for particular uses, like condiment or for wrapping food. Evidence can be used to study further undervalued edible species closely related to the most common food taxa as well as for bioprospection of their nutritional content.

Stem transcriptome screen for selection in wild and cultivated pitahaya (Selenicereus undatus): an epiphytic cactus with edible fruit.

Dragon fruit, pitahaya or pitaya are common names for the species in the Hylocereus group of Selenicereus that produce edible fruit. These Neotropical epiphytic cacti are considered promising underutilized crops and are currently cultivated around the world. The most important species, S. undatus, has been managed in the Maya domain for centuries and is the focus of this article. Transcriptome profiles from stems of wild and cultivated plants of this species were compared. We hypothesized that differences in transcriptomic signatures could be associated with genes related to drought stress. De novo transcriptome assembly and the analysis of differentially expressed genes (DEGs) allowed us to identify a total of 9,203 DEGs in the Hunucmá cultivar relative of wild Mozomboa plants. Of these, 4,883 represent up-regulated genes and 4,320, down-regulated genes. Additionally, 6,568 DEGs were identified from a comparison between the Umán cultivar and wild plants, revealing 3,286 up-regulated and 3,282 down-regulated genes. Approximately half of the DEGs are shared by the two cultivated plants. Differences between the two cultivars that were collected in the same region could be the result of differences in management. Metabolism was the most representative functional category in both cultivars. The up-regulated genes of both cultivars formed a network related to the hormone-mediated signaling pathway that includes cellular responses to auxin stimulus and to hormone stimulus. These cellular reactions have been documented in several cultivated plants in which drought-tolerant cultivars modify auxin transport and ethylene signaling, resulting in a better redistribution of assimilates.

Luxação dorsal complexa da articulação metacarpofalangeana dos dedos longos: relato de caso e revisão da literatura / Complex dorsal dislocation of the metacarpophalangeal joint of the long fingers: case report and literature review

As luxações dorsais da articulação metacarpofalangeana dos dedos são lesões raras, vistas com mais frequência em pacientes jovens, secundárias a trauma por hiperextensão forçada do dedo na mão que estende. São classificadas como simples, quando a redução fechada é possível; ou complexas, quando a redução por métodos fechados não é possível devido à interposição de estruturas periarticulares. É importante distinguir entre uma luxação simples e uma complexa porque sua abordagem e tratamento são diferentes. O objetivo deste estudo é atualizar a abordagem clínica e as diferentes técnicas cirúrgicas utilizadas no tratamento das luxações complexas. Foi realizada uma revisão bibliográfica sobre a luxação dorsal metacarpofalangeana dos dedos longos, excluindo os do polegar, incluindo o Medline (interface PubMed), SciELO e bancos de dados acadêmicos do Google. Todos os artigos revisados concluem que as tentativas de redução incruenta nesses tipos de lesões costumam ser malsucedidas e levar a complicações adicionais. A redução cirúrgica aberta é o método de escolha, permitindo a recuperação anatômica articular com o menor risco de complicações. A imobilização pós-operatória com uma tala de travamento dorsal é recomendada por duas semanas, seguida por reabilitação por terapia ocupacional, esperando-se uma amplitude de movimento normal em seis semanas. A baixa frequência somada ao desconhecimento do médico emergencista ao realizar a manobra de redução pode, muitas vezes, levar à transformação de um simples deslocamento em complexo, tornando-o irredutível e lesionando estruturas adjacentes, por isso, acreditamos ser fundamental conhecer o manejo desta lesão.

Dorsal dislocations of the metacarpophalangeal joint of the fingers are rare injuries that are seen more frequently in young patients secondary to trauma due to forced hyperextension of the finger on the extending hand. They are classified as simple when closed reduction is possible, or complex when reduction by closed methods is not possible given the interposition of peri-articular structures. It is important to distinguish between a simple and complex dislocation because their approach and treatment differ. The objective of this study is to update the clinical approach and the different surgical techniques used in the treatment of complex dislocations. We conducted a bibliographic review on metacarpophalangeal dorsal dislocation of the long fingers, excluding those of the thumb, including the Medline (PubMed interface), SciELO and academic google databases. All the articles reviewed conclude that attempts at closed reduction in these types of injuries are often unsuccessful and often lead to additional complications. Open surgical reduction is the method of choice, allowing joint anatomical recovery with the lowest risk of complications. Postoperative immobilization using a dorsal locking splint is recommended for two weeks followed by rehabilitation by occupational therapy, expecting a normal range of motion at six weeks. The low frequency added to the ignorance of the emergency physician when performing the reduction maneuver can often lead to transform a simple dislocation into a complex one, making it irreducible and injuring adjacent structures, which is why we believe it is essential to know the management of this injury.

Phylogenetic endemism of the orchids of Megamexico reveals complementary areas for conservation.

Orchid diversity provides a unique opportunity to further our understanding of biotic and abiotic factors linked to patterns of richness, endemism, and phylogenetic endemism in many regions. However, orchid diversity is consistently threatened by illegal trade and habitat transformation. Here, we identified areas critical for orchid conservation in the biogeographic province of Megamexico. For this purpose, we evaluated orchid endemism, phylogenetic diversity, and phylogenetic endemism within Megamexico and characterized orchid life forms. Our results indicate that the majority of the regions with the highest estimates of endemism and phylogenetic endemism are in southern Mexico and northern Central America, mostly located on the Pacific side of Megamexico. Among the most important orchid lineages, several belong to epiphytic lineages such as Pleurothallidinae, Laeliinae and Oncidiinae. We also found that species from diverse and distantly related lineages converge in montane forests where suitable substrates for epiphytes abound. Furthermore, the southernmost areas of phylogenetic diversity and endemism of Megamexico are in unprotected areas. Thus, we conclude that the most critical areas for orchid conservation in Megamexico are located in southern Mexico and northern Central America. We recommend that these areas should be given priority by the Mexican system of natural protected areas as complementary conservation areas.

Transcriptional Basis for Haustorium Formation and Host Establishment in Hemiparasitic Psittacanthus schiedeanus Mistletoes.

The mistletoe Psittacanthus schiedeanus, a keystone species in interaction networks between plants, pollinators, and seed dispersers, infects a wide range of native and non-native tree species of commercial interest. Here, using RNA-seq methodology we assembled the whole circularized quadripartite structure of P. schiedeanus chloroplast genome and described changes in the gene expression of the nuclear genomes across time of experimentally inoculated seeds. Of the 140,467 assembled and annotated uniGenes, 2,000 were identified as differentially expressed (DEGs) and were classified in six distinct clusters according to their expression profiles. DEGs were also classified in enriched functional categories related to synthesis, signaling, homoeostasis, and response to auxin and jasmonic acid. Since many orthologs are involved in lateral or adventitious root formation in other plant species, we propose that in P. schiedeanus (and perhaps in other rootless mistletoe species), these genes participate in haustorium formation by complex regulatory networks here described. Lastly, and according to the structural similarities of P. schiedeanus enzymes with those that are involved in host cell wall degradation in fungi, we suggest that a similar enzymatic arsenal is secreted extracellularly and used by mistletoes species to easily parasitize and break through tissues of the host.

Edible native plants of the Gulf of Mexico Province.

Background: Currently, at the global level, human food is mainly based on a few crops extensively cultivated as monocultures. Climate change, changes in land to agriculture and cattle raising, as well as the scarcity of water all affect and reduce the possibility of cultivating alternative crops. One way to face this global problem is to promote the knowledge, production and consumption of native food species on a regional scale.For this study, two databases were constructed for the Gulf of Mexico Province: 1) edible plant species with their corresponding common name, category of use, plant organ(s) utilised as food and type of management; 2) distribution records of these edible species. These species, in addition to being part of the biological diversity of Mexico are of high nutritional, cultural and gastronomical value and have been present in the diet of the inhabitants and ethnic groups in the region since pre-Hispanic times. New information: This study presents the native edible plants of the Gulf of Mexico Province, an area inhabited by 15 ethnic groups. The main novelty of this contribution is the edible plant species database, which includes the records of 482 species that belong to 101 families and 268 genera. We also present information rarely reported in an ethnobotanical inventory: 1) category of food use, 2) category of plant organ used, 3) common name, 4) type of management and 5) the georeferenced distribution of species occurrence in the Gulf of Mexico Province.

Pollen morphology of the genera Hidalgoa and Dahlia (Coreopsideae, Asteraceae): implications for taxonomy.

Hidalgoa and Dahlia are two closely related genera in Asteraceae, tribe Coreopsideae whose limits need to be clarified. Pollen morphology has been useful for delimitation at the genus level in this family. To better define these genera, the morphology of pollen grains was observed and measured using light and scanning electron microscopy. The pollen grains of 25 species of Dahlia and Hidalgoa were acetolyzed and analyzed. Pollen is tricorporate in most of the species studied, although in a few species in Dahlia, grains were found to be hexacolporate. The most outstanding differentiating characters among species of Dahlia and Hidalgoa are colpus length (greater in Hidalgoa) and shape of spines (conical in Hidalgoa). In addition, lalongate ora are larger in Hidalgoa than in Dahlia. A PCA analysis of thirteen pollen characters, identified species of Hidalgoa in a discrete group and Dahliacuspidata as an outlier. These distinctive attributes in pollen morphology support the idea that pollen morphology is useful for delimitation at the generic level in the Dahlia clade. Further evidence from other sources, genetic or anatomical, might contribute to demarcating Dahlia and Hidalgoa, and provide insight into the family's evolutionary history.

Colgajo homodigital a flujo reverso para cobertura de defectos de punta de dedo: serie de casos / Reverse homodigital island flap for coverage of fingertip defects: case series

Introducción y objetivo: Las heridas con pérdida de sustancia en la punta de los dedos son uno de los motivos de consulta más frecuente en urgencias. Las indicaciones del colgajo homodigital a flujo reverso incluyen defectos en zona II y III de Tamai con exposición ósea, limitación para colgajos locales y necesidad de conservar la longitud del dedo.El objetivo de este trabajo es describir los resultados y complicaciones de la reconstrucción de defectos de punta de dedo con colgajo homodigital a flujo reverso utilizando la técnica con y sin resensibilización del colgajo, en base a la experiencia de los autores.Material y método.Presentamos una serie de 6 casos con heridas de punta de dedo con pérdida de sustancia operados por los autores en el año 2020. Se realizó en todos los casos un colgajo homodigital a flujo reverso, en 2 de ellos con resensibilización.Resultados.Los pacientes fueron todos varones, en su mayoría trabajadores manuales, con rango de edad entre 20 a 38 años. Presentaban amputación a nivel de zona II y III de los dedos, transversal u oblicua palmar, excluido el pulgar. Las radiografías simples en el preoperatorio mostraban compromiso de la falange distal.No registramos complicaciones a los 6 meses. En cuanto al arco de flexión de los dígitos, todos presentaron movilidad conservada con aceptable recuperación sensitiva.Conclusiones.Nuestros resultados utilizando el colgajo homodigital a flujo reverso para heridas de punta de dedo coinciden con la literatura en cuanto a las ventajas de la técnica, sin presentar complicaciones. Si bien este trabajo contribuye a la evidencia ilustrando la experiencia local, seguimos registrando los casos para lograr un mayor número de pacientes y mejor nivel de evidencia. (AU)

Background and objective: Wounds with loss of substance in fingertips are one of the most frequent reasons for consultation in the emergency room. Treatment options are varied, and the choice will depend primarily on the injury pattern and topography. A technique that is indicated in cases of extensive substance loss is the reverse flow homodigital flap. This procedure is performed in one surgical time, provides good results, has a wide arc of rotation and offers stable coverage with good vascularization and acceptable sensory recovery.The purpose of this paper is to show the authors experience in reconstruction of finger tip defects with homodigital flap in reverse flow.Methods.We present a series of 6 patients with finger tip wounds with loss of substance, operated by the authors in 2020, using a reverse flow homodigital flap performing resensitization using neurorraphy to the contralateral collateral nerve in 2 cases.Results.Patients were all male, most of them manual workers, with an age range from 20 to 38 years. They presented amputation at the zone II and III level of the fingers, transverse or oblique palmar, excluding the thumb. Preoperative plain radiographs showed involvement of the distal phalanx. The follow-up of the patients was 6 months. There were no complications. Regarding the flexion arc of the digits, all presented preserved mobility, with an acceptable sensory recovery.Conclusions.Our results are similar with international literature, regarding the advantages of this technique. This work shows our experience with this flap. We will continue collecting cases in order to increase the level of evidence. (AU)

Get the shovel: morphological and evolutionary complexities of belowground organs in geophytes.

Herbaceous plants collectively known as geophytes, which regrow from belowground buds, are distributed around the globe and throughout the land plant tree of life. The geophytic habit is an evolutionarily and ecologically important growth form in plants, permitting novel life history strategies, enabling the occupation of more seasonal climates, mediating interactions between plants and their water and nutrient resources, and influencing macroevolutionary patterns by enabling differential diversification and adaptation. These taxa are excellent study systems for understanding how convergence on a similar growth habit (i.e., geophytism) can occur via different morphological and developmental mechanisms. Despite the importance of belowground organs for characterizing whole-plant morphological diversity, the morphology and evolution of these organs have been vastly understudied with most research focusing on only a few crop systems. Here, we clarify the terminology commonly used (and sometimes misused) to describe geophytes and their underground organs and highlight key evolutionary patterns of the belowground morphology of geophytic plants. Additionally, we advocate for increasing resources for geophyte research and implementing standardized ontological definitions of geophytic organs to improve our understanding of the factors controlling, promoting, and maintaining geophyte diversity.

Systematic relevance of pollen morphology in tribe Hylocereeae (Cactaceae).

Hylocereeae is one of the nine tribes in the subfamily Cactoideae (Cactaceae), for which the limits and recognition of genera have been controversial. Essentially, this group comprises epiphytic and hemiepiphytic genera with stems modified as climbing structures. The aim of this paper is to examine pollen attributes in representative species of genera of Hylocereeae, focusing on Selenicereus whose current circumscription comprises Hylocereus and three Weberocereus species, to find whether significant potentially apomorphic and/or autapomorphic systematic characters can be discovered. Utilizing SEM and light microscopy, 25 pollen characters were observed and measured. Tribe Hylocereeae is stenopalynous, with pollen grains isopolar and radially symmetrical monads, mostly tricolpate, except in Kimnachia, Pseudoripsalis and Weberocereus, whose pollen grains are pantocolpate. Seven attributes (five qualitative and two continuous) exhibited useful variation and were coded. The character of brevicolpate pollen grains was shared by Kimnachia ramulosa and Pseudorhipsalis amazonica. Convex quadrangular outline in the polar view was shared by Weberocereus tunilla and S. glaber. The absence of spinules on the exine was shared by S. minutiflorus and S. stenopterus. The largest pollen grain, found in Selenicereus megalanthus, might be correlated with polyploidy. Selenicereus is the taxon with the highest variation in pollen attributes, including species with an exine with or without spinules and variable polar area index and shape (subprolate or oblate-spheroidal).

Ups and downs: Genetic differentiation among populations of the Podocarpus (Podocarpaceae) species in Mesoamerica.

The biogeographical history of Mesoamerican cloud forests is complex, encompassing a diverse and heterogeneous mixture of species with temperate and tropical origins. The dynamic geological landscape and climate change from the Miocene to the Pleistocene affected the distributions and composition of cloud forests in the region, and contributed to divergence events at different time scales. We assessed genetic variation of 29 populations of P. matudae, and closely related P. guatemalensis and P. oleifolius (Podocarpaceae) by sequencing 255 samples of the psbA-trnH and trnL-F intergenic spacer regions across the species ranges. We conducted phylogenetic, population and spatial genetic analyses as well as divergence time estimation and ecological niche modelling (ENM) to test the generality of demographic and genetic scenarios for cloud forest-adapted species. The results revealed genetic differentiation among species, with some individuals of P. oleifolius and P. guatemalensis placed in the P. matudae group and some P. oleifolius in the P. guatemalensis group. Predictions of ENMs under past climatic conditions and a strong signal of spatial expansion suggest that the highland P. matudae and P. oleifolius populations experienced expansions into lower elevation during the Last Glacial Maximum (LGM). Contrary to predictions by the two precipitation models and elevational ups and downs for cloud forest taxa during the LGM, genetic differentiation and predicted distribution of suitable habitat support the hypotheses that P. matudae and P. oleifolius remained in situ during the LGM primarily within the current fragmented distribution of the cloud forest and spread into the lowlands during the LGM, whereas the distribution of suitable habitat for P. guatemalensis had no major changes upwards from the Last Inter Glacial (LIG) to current conditions.

Climate change and conservation in a warm North American desert: effect in shrubby plants.

BACKGROUND: Deserts are biologically rich habitats with a vast array of animals and plants adapted to xeric conditions, and most deserts are among the planet's last remaining areas of total wilderness. Among North American deserts, the Chihuahuan Desert has the highest levels of diversity and endemism. To understand the effect of future climate change on plants distributed in this arid land and propose effective conservation planning, we focused on five endemic shrubby species that characterize the Chihuahuan Desert and used an integrative approach. METHODS: Ecological niche-based modeling, spatial genetics and ecological resistance analyses were carried out to identify the effect of global warming on the studied five shrubby species. Key areas that need to be preserved were identified taking into account the existing protected areas within the Chihuahuan Desert. RESULTS: The extent of future distribution will vary among these species, and on average expansion will occur in the western part of the Chihuahuan Desert. For most species low environmental resistance to gene flow was predicted, while higher future resistance was predicted for one species that would lead to increased population isolation. The highest haplotype diversity was identified in three hotspots. Based on future suitability of habitat and in the haplotype diversity we suggest preserving two hotspots of genetic diversity in the Sierra Madre Oriental, located in areas without protection. The third hotspot was detected in the well preserved Tehuacán-Cuicatlán Man and Biosphere Reserve. CONCLUSION: Global climate change will have an effect in arid adapted plants, favoring expansion in the western of the Chihuahuan Desert however negatively affecting others with high ecological resistance disrupting gene flow. Two hotspots of genetic diversity in the Sierra Madre Oriental should be protected.

Spatio-temporal evolution of climbing habit in the Dahlia-Hidalgoa group (Coreopsidae, Asteraceae).

In this paper we focus on Hidalgoa, a small genus distributed in cloud forest from Mexico to Colombia with the uncommon climbing habit of enlarging its petioles. This genus belongs to tribe Coreopsideae (Asteraceae), a group mostly from the Neotropics with a few taxa in Oceania and Polynesia. The phylogenetic position of Hidalgoa has not yet been determined though it will most probably be closely related to Dahlia. The aim of this paper is to understand the ecological and evolutionary consequences of the shift to a climbing growth form using a spatio-temporal approach to phylogenetic analyses, and by testing evolutionary models for ecological niche. Our results identified that Hidalgoa formed a sub- clade in a grade with Dahlia, with divergence occurring in the Pliocene. The ancestral life form for this clade was cryptophytic (e.g. geophytes). Analyses using the climate variables most important to the elements of the Dahlia-Hidalgoa clade indicate that they share the same preferences. Moreover, visualization by traitgrams of the significant climate variables shows no departure among clades. These results suggest that no evolutionary or ecological consequences have yet manifested, and that Hidalgoa can be considered a climbing Dahlia.

Anther development in tribe Epidendreae: orchids with contrasting pollination syndromes.

BACKGROUND: Epidendreae is one of the most diverse tribes among the orchids with remarkable variation in life form, floral morphology and pollination syndromes. Its circumscription was recently revised and subtribes Agrostophyllinae and Calypsoinae were transferred into this tribe. One of the principal floral characters utilized in classification of orchids is the incumbency or bending of the column. This study records and compares late stages of anther, column and lip development, and discusses anther characters in fifteen representative taxa of five of the six subtribes in Epidendreae with respect to classification and pollination biology. METHODS: A series of late floral stages were sampled and fixed for examination under scanning electron microscope. RESULTS: Anther incumbency or bending in this group varies from 90° to almost 180°. Incumbency in the late stages of development is reached in Bletiinae, Ponerinae, Pleurothallidinae and Laeliinae whereas incumbency is reached early in its development in Corallorhiza and Govenia of Calypsoinae. DISCUSSION: Our observations indicate that the position of Chysis in subtribe Bletiinae needs revision based on differences in a number floral, and in particular of anther characters; and that Coelia only shares the early anther incumbency with Calypsoinae members, but not the rest of floral and anther characters. Anatomical characters such as crystals around the actinocytic stomata on the anther cap and sugar crystals in Laeliinae; lack of rostellum in Bletiinae; coalescent anther with the column, lack of trichomes and papillae on lip keels, and underdeveloped rostellum in Chysis; a mechanism by which the anther cap comes off (it is joined with the grooved lip by a claw) in Isochilus are all related to pollination syndromes and reproductive biology.

Influence of current climate, historical climate stability and topography on species richness and endemism in Mesoamerican geophyte plants.

BACKGROUND: A number of biotic and abiotic factors have been proposed as drivers of geographic variation in species richness. As biotic elements, inter-specific interactions are the most widely recognized. Among abiotic factors, in particular for plants, climate and topographic variables as well as their historical variation have been correlated with species richness and endemism. In this study, we determine the extent to which the species richness and endemism of monocot geophyte species in Mesoamerica is predicted by current climate, historical climate stability and topography. METHODS: Using approximately 2,650 occurrence points representing 507 geophyte taxa, species richness (SR) and weighted endemism (WE) were estimated at a geographic scale using grids of 0.5 × 0.5 decimal degrees resolution using Mexico as the geographic extent. SR and WE were also estimated using species distributions inferred from ecological niche modeling for species with at least five spatially unique occurrence points. Current climate, current to Last Glacial Maximum temperature, precipitation stability and topographic features were used as predictor variables on multiple spatial regression analyses (i.e., spatial autoregressive models, SAR) using the estimates of SR and WE as response variables. The standardized coefficients of the predictor variables that were significant in the regression models were utilized to understand the observed patterns of species richness and endemism. RESULTS: Our estimates of SR and WE based on direct occurrence data and distribution modeling generally yielded similar results, though estimates based on ecological niche modeling indicated broader distribution areas for SR and WE than when species richness was directly estimated using georeferenced coordinates. The SR and WE of monocot geophytes were highest along the Trans-Mexican Volcanic Belt, in both cases with higher levels in the central area of this mountain chain. Richness and endemism were also elevated in the southern regions of the Sierra Madre Oriental and Occidental mountain ranges, and in the Tehuacán Valley. Some areas of the Sierra Madre del Sur and Sierra Madre Oriental had high levels of WE, though they are not the areas with the highest SR. The spatial regressions suggest that SR is mostly influenced by current climate, whereas endemism is mainly affected by topography and precipitation stability. CONCLUSIONS: Both methods (direct occurrence data and ecological niche modeling) used to estimate SR and WE in this study yielded similar results and detected a key area that should be considered in plant conservation strategies: the central region of the Trans-Mexican Volcanic Belt. Our results also corroborated that species richness is more closely correlated with current climate factors while endemism is related to differences in topography and to changes in precipitation levels compared to the LGM climatic conditions.

Colonization in North American Arid Lands: The Journey of Agarito (Berberis trifoliolata) Revealed by Multilocus Molecular Data and Packrat Midden Fossil Remains.

Here we conduct research to understand the evolutionary history of a shrubby species known as Agarito (Berberis trifoliolata), an endemic species to the Chihuahuan Desert. We identify genetic signatures based on plastid DNA and AFLP markers and perform niche modelling and spatial connectivity analyses as well as niche modelling based on records in packrats to elucidate whether orogenic events such as mountain range uplift in the Miocene or the contraction/expansion dynamics of vegetation in response to climate oscillations in the Pliocene/Pleistocene had an effect on evolutionary processes in Agarito. Our results of current niche modelling and palaeomodelling showed that the area currently occupied by Berberis trifoliolata is substantially larger than it was during the Last Interglacial period and the Last Glacial Maximum. Agarito was probably confined to small areas in the Northeastern and gradually expanded its distribution just after the Last Glacial Maximum when the weather in the Chihuahuan Desert and adjacent regions became progressively warmer and drier. The most contracted range was predicted for the Interglacial period. Populations remained in stable areas during the Last Glacial Maximum and expanded at the beginning of the Holocene. Most genetic variation occured in populations from the Sierra Madre Oriental. Two groups of haplotypes were identified: the Mexican Plateau populations and certain Northeastern populations. Haplogroups were spatially connected during the Last Glacial Maximum and separated during interglacial periods. The most important prediction of packrat middens palaeomodelling lies in the Mexican Plateau, a finding congruent with current and past niche modelling predictions for agarito and genetic results. Our results corroborate that these climate changes in the Pliocene/Pleistocene affected the evolutionary history of agarito. The journey of agarito in the Chihuahuan Desert has been dynamic, expanding and contracting its distribution range and currently occupying the largest area in its history.

Historical reconstruction of climatic and elevation preferences and the evolution of cloud forest-adapted tree ferns in Mesoamerica.

BACKGROUND: Cloud forests, characterized by a persistent, frequent or seasonal low-level cloud cover and fragmented distribution, are one of the most threatened habitats, especially in the Neotropics. Tree ferns are among the most conspicuous elements in these forests, and ferns are restricted to regions in which minimum temperatures rarely drop below freezing and rainfall is high and evenly distributed around the year. Current phylogeographic data suggest that some of the cloud forest-adapted species remained in situ or expanded to the lowlands during glacial cycles and contracted allopatrically during the interglacials. Although the observed genetic signals of population size changes of cloud forest-adapted species including tree ferns correspond to predicted changes by Pleistocene climate change dynamics, the observed patterns of intraspecific lineage divergence showed temporal incongruence. METHODS: Here we combined phylogenetic analyses, ancestral area reconstruction, and divergence time estimates with climatic and altitudinal data (environmental space) for phenotypic traits of tree fern species to make inferences about evolutionary processes in deep time. We used phylogenetic Bayesian inference and geographic and altitudinal distribution of tree ferns to investigate ancestral area and elevation and environmental preferences of Mesoamerican tree ferns. The phylogeny was then used to estimate divergence times and ask whether the ancestral area and elevation and environmental shifts were linked to climatic events and historical climatic preferences. RESULTS: Bayesian trees retrieved Cyathea, Alsophyla, Gymnosphaera and Sphaeropteris in monophyletic clades. Splits for species in these genera found in Mesoamerican cloud forests are recent, from the Neogene to the Quaternary, Australia was identified as the ancestral area for the clades of these genera, except for Gymnosphaera that was Mesoamerica. Climate tolerance was not divergent from hypothesized ancestors for the most significant variables or elevation. For elevational shifts, we found repeated change from low to high elevations. CONCLUSIONS: Our data suggest that representatives of Cyatheaceae main lineages migrated from Australia to Mesoamerican cloud forests in different times and have persisted in these environmentally unstable areas but extant species diverged recentrly from their ancestors.

Munroa argentina, a Grass of the South American Transition Zone, Survived the Andean Uplift, Aridification and Glaciations of the Quaternary.

The South American Transition Zone (SATZ) is a biogeographic area in which not only orogeny (Andes uplift) and climate events (aridification) since the mid-Miocene, but also Quaternary glaciation cycles had an important impact on the evolutionary history of the local flora. To study this effect, we selected Munroa argentina, an annual grass distributed in the biogeographic provinces of Puna, Prepuna and Monte. We collected 152 individuals from 20 localities throughout the species' range, ran genetic and demographic analyses, and applied ecological niche modeling. Phylogenetic and population genetic analyses based on cpDNA and AFLP data identified three phylogroups that correspond to the previously identified subregions within the SATZ. Molecular dating suggests that M. argentina has inhabited the SATZ since approximately 3.4 (4.2-1.2) Ma and paleomodels predict suitable climate in these areas during the Interglacial period and the Last Glacial Maximum. We conclude that the current distribution of M. argentina resulted from the fragmentation of its once continuous range and that climate oscillations promoted ecological differences that favored isolation by creating habitat discontinuity.

Origin and evolution of fleshy fruit in woody bamboos.

Several hypotheses have been suggested to explain the origin of fleshy fruit in monocots. One is that they originated in the understory of tropical regions and another is that fleshy fruit originated in tropical rainforests where high year-round rainfall implies that seasonality is not a limiting factor. Here we identify the time of origin and ecological preferences of woody bamboos to understand the evolution of the fleshy fruit known as the bacoid caryopsis. Bayesian Inference, Maximum Likelihood and molecular dating analyses were run based on eight plastid and two nuclear regions for 68 bamboo species. Climate data and soil parameters were gathered for 464 localities for these species. The ancestral type of caryopsis was reconstructed by parsimony. According to these analyses the bacoid caryopsis may have evolved independently seven times from the Late Miocene to the Early Pliocene and Mid-Pliocene to Mid-Pleistocene via convergent evolution. Our results suggest that in bamboos neither current climatic variables nor soil parameters were significantly correlated with the appearance of this type of fruit, nor do they have a phylogenetic signal. It is remarkable, however, that the first appearance of the bacoid caryopsis in bamboos might be associated with historical preferences for warmer and wetter climate during the Miocene. Further research is needed to identify whether other factors, such as vivipary or dispersal by small animals, rather than climate, could be responsible for the evolution of this trait in woody bamboos.

Origin and diversification of the Milla Clade (Brodiaeoideae, Asparagaceae): a Neotropical group of six geophytic genera.

The Milla clade currently comprises six genera of geophytic plants distributed from Arizona to Guatemala. Three genera (Behria, Jaimehintonia and Petronymphe) are monotypic while the remaining genera (Bessera, Dandya and Milla) contain from two to ten (Milla) species. Parsimony, Maximum Likelihood and Bayesian Inference analyses were conducted with plastid and nuclear DNA sequences from a total of 181 plants belonging to 15 species in all six genera. Molecular dating was performed under a relaxed clock model. We examined the phylogenetic relationships of the genera and species, estimated origin-divergence times for the clade and genera and determined the ancestral distribution area of the clade by optimizing ancestral areas given current biogeographic distributions. The phylogenetic results suggest that final decisions on limits of the six genera in the Milla clade will have to be established until further taxonomic work is completed for Milla, in particular for the group of populations included under the name M. biflora. The later genus is rendered polyphyletic by other genera of the family. The origin of the Milla clade is estimated at 15.8Ma. Ancestral area of the clade most likely was located in the California Floristic Province and dispersal occurred most likely to the Chihuahuan-Coahuila Plateaus and the Trans-Mexican Volcanic Belt and from there to Baja California and the Sierra Madre del Sur. Two hypotheses that need further testing are proposed to explain complex relationships of genera and polyphyly of Milla, one in relation to fragmentation of populations and pollinator shifts and another suggesting that populations remained in refugia in the Trans-Mexican Volcanic Belt.