A New Masdevallia (Pleurothallidinae: Orchidaceae) from the White-Sand Forests of the Central Amazon, Brazil

Masdevallia britoi, a new species in Masdevallia sect. Minutae, is described and illustrated from the central Amazon in Brazil. It is similar to M. wendlaniana but differs by shorter sepals that are internally white, shorter oblong petals with a delicate tooth near the middle, shorter lip with deltoid marginal folds near the middle and three-denticulate apex, and shorter ovary. The new species grows in the white-sand forests locally known with the name Campinaranas. We also provide an identification key for the species of Masdevallia from the Brazilian Amazon.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Jardín Botánico Lankester (JBL

Nuclear–plastid discordance indicates past introgression in Epidendrum species (Laeliinae: Orchidaceae) with highly variable chromosome numbers.

Here we study a challenging group of karyotypically highly variable Epidendrum spp. using phylogenetic methods to help understand how hybridization/introgression contributes to karyotype evolution. We hypothesize that species with great chromosome number variation are a result of past hybridization/introgression. Conflicting topologies in trees constructed using separate plastid and nuclear datasets suggest past hybridization events that occurred most probably at least 3.7 Mya. A basic number x = 14 and substantial karyotype change followed by species divergence are suggested. Descending dysploidy and polyploidy were the most frequent changes estimated across the phylogenetic tree of the group. Two species, Epidendrum secundum and E. xanthinum, have probably experienced unidirectional gene flow involving their ancestors (the pollen recipients) and ancestors of E. puniceoluteum and E. denticulatum/E. flammeum, respectively, the pollen donors. However, it is not possible to say whether hybridization participated in the origin of E. secundum and E. xanthinum or merely contributed to their genomic divergence and karyotype change through introgression as has been observed in modern hybrid zones in Epidendrum. This pattern of introgression causing karyotype disruption and divergence could help explain the enigma of some highly diverse genera, such as Epidendrum. Further studies using a wider sampling of the genus could test if gene flow and karyotype variability are associated with the increase of speciation rates

Molecular phylogenetics of Maranta (Marantaceae: Zingiberales): non-monophyly and support for a wider circumscription.

Neotropical Maranta has repeatedly emerged as non-monophyletic in molecular phylogenetic studies, but no taxonomic changes have been proposed due to previous weak support for the main clades and overall sparse taxonomic sampling. Our study includes a phylogenetic hypothesis strictly based on molecular evidence, using nuclear ribosomal (nrITS) and plastid (rps16, trnL-F and rpl32-trnL) markers for Maranta and allied genera. Thirty-two species from eight genera were sampled, and maximum likelihood (ML) and Bayesian inference (BI) analyses were carried out. Non-ambiguous indels were scored in both analyses to test their contribution to internal support. Our results confirm that Maranta, as previously delimited, is non-monophyletic, with species of Hylaeanthe, Myrosma and Koernickanthe nested among clades of Maranta. The combined BI analysis without indels was the best resolved, and inclusion of indels increased support only for terminal clades. The sampled species comprise two sister clades, one with Maranta + Hylaeanthe + Myrosma + Koernickanthe and the other with Ctenanthe + Saranthe + Stromanthe. The infrageneric classification proposed by Schumann for Maranta (M. subgenera Maranta and Calateastrum) is partially corroborated by our results, but the remaining subgenera need to be further studied. Based on our strongly supported phylogenetic results, we revise the taxonomy of these genera, expanding the limits of Maranta. We propose two new combinations and a new name for Hylaeanthe in Maranta

The role of Quaternary glaciations in shaping biogeographic patterns in a recently evolved clade of South American epiphytic orchids.

To contribute to what is known about involvement of vegetation dynamics in Neotropical speciation, we used the Epidendrum latilabre complex, a taxonomically well-defined species group, to investigate past connections between Amazonian (AM) and Atlantic (AF) forests and address the following topics: (1) divergence times between sister species currently distributed in AM and AF; (2) distribution patterns of ancestral species of the E. latilabre complex and (3) potential routes connecting ancestral ranges between AM and AF. We developed a robust phylogenetic estimate for species of the E. latilabre complex by sequencing two nuclear and six plastid loci. Then, we combined divergence time estimation, ancestral range reconstruction and ecological niche modelling. Our biogeographic reconstruction exhibits a complex pattern of connections among tropical forests east of the Andes in South America. The AM and AF species of the E. latilabre complex are intermixed in the results, and climatic shifts during the Pleistocene (Chibanian) are suggested here as a major force promoting speciation. Sister species tend to be ecologically distinct in their climate niche spaces, and vicariance and peripheral isolation are reconstructed as the main drivers of speciation. There is evidence to suggest that the south-east/north-west bridge and the northern/north-eastern coastal route have been occupied by the ancestors of the E. latilabre complex, and alternative routes across the South American dry diagonal were unlikely. Further studies on Neotropical epiphytic taxa are still necessary for understanding the dynamics of historical connections between AM and AF

Too many species: morphometrics, molecular phylogenetics and genome structure of a Brazilian species complex in Epidendrum (Laeliinae; Orchidaceae) reveal fewer species than previously thought

In this study, we analyse a species complex in Epidendrum, a mega-diverse Neotropical orchid genus, that is formed by the 11 Brazilian species of the E. difforme group. Although this group (c. 100 taxa) exhibits relatively high levels of floral variation, the Brazilian species are similar, making delimitation problematic. Here we combine molecular (phylogenetics), morphological (geometric morphometrics), genome size and cytogenetic (chromosome counts and CMA/DAPI staining) data to investigate circumscription of these species. Our results were interpreted by looking for congruence of the results as a means to delimit species. The studied taxa appear to be monophyletic, and karyotypically all analysed accessions were 2n = 40. Their 1C values vary from 1.99 ± 07 pg to 2.84 ± 0.12 pg. We did not find evidence for recent polyploidy or dysploidy and, apparently, these phenomena have not been important in the evolution of this species complex. On the other hand, we found high levels of polymorphism for CMA/DAPI banding, and variation in genome size appears to be positively correlated with latitude. Geometric morphometrics indicate that E. sanchezii and E. anatipedium/E. amarajiense are distinct from the remaining species, and three groups of other species can be separated using canonical variables analysis (CVA). Variation in lip shape, genome size and heterochromatin patterns of the taxa are not fully congruent with the phylogenetic analysis, but our results allowed us to delimit with full confidence four species: E. amapense, E. anatipedium (including E. amarajiense), E. pseudodifforme (including E. campaccii and E. thiagoi) and E. sanchezii. Four others will be tentatively maintained but need further study. Our results indicate that it will be necessary to reassess many of the species complexes in the genus using a similar multidisciplinary perspective to evaluate the number of taxa that should be recognized

Evolutionary history and systematics of Campylocentrum (Orchidaceae: Vandeae: Angraecinae): a phylogenetic and biogeographical approach

Subtribe Angraecinae (Orchidaceae: Vandeae) are mainly distributed in Africa, but with two genera, Campylocentrum and Dendrophylax, restricted to the Neotropics. As a widespread Neotropical genus, Campylocentrum constitutes an appropriate model for revealing biogeographical patterns in this area and investigating routes of colonization and dispersal. In this study, we reconstructed phylogenetic relationships of the genus with Bayesian inference and maximum parsimony analyses of combined nuclear (ITS rDNA and Xdh) and plastid (matK exon, rpl32-trnL spacer, trnL intron, trnL-trnF spacer and ycf1 exon) DNA datasets, aimed at establishing a new infrageneric classification for this taxonomically complex genus. Based on the most comprehensive phylogenetic tree, we investigated the biogeographical history of Campylocentrum by estimating divergence times, inferred using fossil and secondary calibrations applying a relaxed-clock model approach, and reconstructing ancestral areas of distribution under a time-stratified likelihood model. The phylogenetic analyses provided strong support for the majority of the clades. Campylocentrum is monophyletic, and we recognize five sections based upon strongly supported clades. We conclude that the African angraecoid ancestor of Campylocentrum and Dendrophylax dispersed to the Antilles. Campylocentrum is estimated to be a relatively young genus (late Miocene, c. 8.2 Mya) and its most recent common ancestor had a disjunct distribution in the Antilles and Parana dominion. During the Pliocene, the five sections diverged and expanded their distributions in the Neotropics, and in the Pleistocene diversification was experienced by some of the terminal clades. We hypothesize that the evolutionary history of Campylocentrum was strongly influenced by orogenic events during the Pliocene and climatic fluctuations during the PleistoceneUniversidad de Costa Rica/[814-B5-A87]/UCR/Costa RicaNational Science Foundation/[DEB-0946618]/NSF/Estados UnidosUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Jardín Botánico Lankester (JBL

Growing knowledge: an overview of Seed Plant diversity in Brazil

Abstract An updated inventory of Brazilian seed plants is presented and offers important insights into the country's biodiversity. This work started in 2010, with the publication of the Plants and Fungi Catalogue, and has been updated since by more than 430 specialists working online. Brazil is home to 32,086 native Angiosperms and 23 native Gymnosperms, showing an increase of 3% in its species richness in relation to 2010. The Amazon Rainforest is the richest Brazilian biome for Gymnosperms, while the Atlantic Rainforest is the richest one for Angiosperms. There was a considerable increment in the number of species and endemism rates for biomes, except for the Amazon that showed a decrease of 2.5% of recorded endemics. However, well over half of Brazillian seed plant species (57.4%) is endemic to this territory. The proportion of life-forms varies among different biomes: trees are more expressive in the Amazon and Atlantic Rainforest biomes while herbs predominate in the Pampa, and lianas are more expressive in the Amazon, Atlantic Rainforest, and Pantanal. This compilation serves not only to quantify Brazilian biodiversity, but also to highlight areas where there information is lacking and to provide a framework for the challenge faced in conserving Brazil's unique and diverse flora