Patrícia Luz Ribeiro

Demography, and genetic and morphological variability of the endangered Sophronitis sincorana (Orchidaceae) in the Chapada Diamantina, Brazil

We carried out a demographic study and evaluated the genetic and morphological variability in five populations of the endangered Sophronitis sincorana (Orchidaceae) endemic to Northeastern Brazil, based on allozyme and morphometric analyses. Plant density was approximately 0.5 plants/m2, and the projected total number of plants was approximately 50,000 individuals. However, fruit set and recruitment of individuals are rare. The genetic variability was very high in all populations (P = 100, A = 3.0−3.5, He = 0.33−0.48), and all populations presented similar values of morphological variability. Low genetic and morphological structuring were found in the species (FST = 0.053, AMRPP = 0.018). The elevated coefficient of endogamy encountered in populations of S. sincorana indicates the occurrence of structuring within the populations. The lack of correlation between morphological and genetic variation in this species indicates that none of the markers examined should be used separately for either conservation purposes.

Spatial analyses of the phylogenetic diversity of Minaria (Apocynaceae): assessing priority areas for conservation in the Espinhaço Range, Brazil

The protection of areas that shelter high evolutionary diversity represented by geographically and phylogenetically isolated lineages is becoming an important conservation strategy. Nevertheless, the spatial distribution of this component of biodiversity is still unknown for most groups, which limits its application for selecting priority areas to conserve. In the present study, we reconstructed the phylogeny of Minaria (Apocynaceae) based on plastid (trnH-psbA, rps16, trnS-trnG and trnD-trnT) and nuclear (ITS and ETS) DNA markers and 34 morphological characters, and analysed the geographic distribution of the phylogenetic diversity (PD) and endemism (PE) in this genus. Minaria includes 21 species that are highly concentrated in the Espinhaço Range, in eastern Brazil, most of which (∼75%) are narrowly distributed. The spatial analyses of PD and PE of Minaria indicate four evolutionary relevant areas in this region. The Serra do Cipó and the Diamantina Plateau contain 10 endemic species and present the highest levels of PD. However, the two other areas also deserve special attention. Rio de Contas has high levels of PE, because of two endemic sister species that represent a phylogenetically isolated lineage and the Southern Espinhaço Range houses the most critically endangered species of the genus. Most endemic species of Minaria occur in vegetation islands on rocky outcrops (campos rupestres). These low-fuel areas are less susceptible to fire, suggesting that the Espinhaço Range has served as a historical refuge for fire-sensitive lineages. Our results suggest that conservation units in the Espinhaço Range cover a great proportion of the evolutionary diversity of Minaria and that fire management is probably an important strategy to preserve this endemic biodiversity.

Taxonomic Considerations on Metastelmatinae (Apocynaceae) Based on Plastid and Nuclear DNA

Abstract The Metastelmatinae (Asclepiadoideae, Apocynaceae) include 13 genera and approximately 260 species with complex morphological affinities that are broadly distributed in the Neotropics. This study investigated phylogenetic relationships within this subtribe using plastid (trnT-F, trnS-G, trnH-psbA, trnD-T, rps16, and matK) and nuclear (ITS) markers. The taxonomic sampling focused on the South American species, and included approximately 25% of the subtribe. Individual data partitions, and combined datasets were analyzed using Bayesian inference, maximum likelihood, and maximum parsimony. The results indicated that most genera of Metastelmatinae are not monophyletic. Internal relationships in the subtribe and key morphological characters used in the taxonomy of the group are discussed. The lack of resolution in the molecular phylogeny, incongruent phylogenetic signals between plastid and nuclear datasets, and the lack of morphological features for individual clades prevented major taxonomic changes in this group, those of which were restricted to the inclusion of Barjonia harleyi and Hemipogon harleyi into Minaria forming the new combinations Minaria harleyi and M. volubilis , and the synonymy of Macroditassa under Peplonia with the new combinations Peplonia adnata and P. macrophylla .

Plant diversification in the Espinhaço Range: Insights from the biogeography of Minaria (Apocynaceae)

The Espinhaco Range, eastern Brazil, is a region with remarkable floristic diversity and endemism, which are mainly concentrated in the campo rupestre. Minaria (Apocynaceae) is a genus with 21 species, most of which are endemic to the Espinhaco Range. In the present study, we investigated the biogeography of Minaria as the basis for understanding the origin and maintenance of plant diversity and endemism in the campo rupestre of the Espinhaco Range. We assessed the ecological divergence between clades, reconstructed the historical biogeography and dated the phylogeny of Minaria based on plastid and nuclear DNA. According to our estimates, Minaria arose in the Espinhaco Range during the Neogene. Its distribution is postulated to have been driven by a trend toward long-term retraction, interrupted by a few episodes of expansion. Ecologically, Minaria species do not present any obvious innovations that could explain their diversification by adaptive radiation. Appar- ently, the higher-altitude rocky savannas in the Espinhaco Range have offered stable environments in which dry seasons and fire regimes are less intense than in savannas at lower altitudes. Isolated on rocky outcrops, lineages would be more likely to differentiate by non-adaptive radiation, which may result in high plant diversity and endemism.

Using multiple analytical methods to improve phylogenetic hypotheses in Minaria (Apocynaceae).

Metastelmatinae is a neotropical subtribe of Asclepiadoideae (Apocynaceae), comprising 13 genera and around 260 species whose phylogenetic relationships are often unresolved or incongruent between plastid and nuclear datasets. The genus Minaria is one of the first lineages to emerge in the Metastelmatinae and is highly supported based on plastid markers. It comprises 21 species, most of which are endemic to small areas with open vegetation in the Espinhaço Range, Brazil. In the work presented here, we use plastid (rps16, trnH-psbA, trnS-trnG, and trnD-trnT) and nuclear (ITS and ETS) datasets to investigate the relationships within Minaria. We show that the three methods mostly used in phylogenetic studies, namely, maximum parsimony, maximum likelihood, and Bayesian Inference, have different performances and that a pluralistic analytical approach combining results from them can increase tree resolution and clade confidence, providing valuable phylogenetic information.