Phylogeny of Campanuloideae (Campanulaceae) with Emphasis on the Utility of Nuclear Pentatricopeptide Repeat (PPR) Genes

Background

The Campanuloideae (Campanulaceae) are a highly diverse clade of angiosperms found mostly in the Northern Hemisphere, with the highest diversity in temperate areas of the Old World. Chloroplast markers have greatly improved our understanding of this clade but many relationships remain unclear primarily due to low levels of molecular evolution and recent and rapid divergence. Furthermore, focusing solely on maternally inherited markers such as those from the chloroplast genome may obscure processes such as hybridization. In this study we explore the phylogenetic utility of two low-copy nuclear loci from the pentatricopeptide repeat gene family (PPR). Rapidly evolving nuclear loci may provide increased phylogenetic resolution in clades containing recently diverged or closely related taxa. We present results based on both chloroplast and low-copy nuclear loci and discuss the utility of such markers to resolve evolutionary relationships and infer hybridization events within the Campanuloideae clade.

Results

The inclusion of low-copy nuclear genes into the analyses provides increased phylogenetic resolution in two species-rich clades containing recently diverged taxa. We also obtain support for the placement of two early diverging lineages (Jasione and Musschia-Gadellia clades) that have previously been unresolved. Furthermore, phylogenetic analyses of PPR loci revealed potential hybridization events for a number of taxa (e.g., Campanula pelviformis and Legousia species). These loci offer greater overall topological support than obtained with plastid DNA alone.

Conclusion

This study represents the first inclusion of low-copy nuclear genes for phylogenetic reconstruction in Campanuloideae. The two PPR loci were easy to sequence, required no cloning, and the sequence alignments were straightforward across the entire Campanuloideae clade. Although potentially complicated by incomplete lineage sorting, these markers proved useful for understanding the processes of reticulate evolution and resolving relationships at a wide range of phylogenetic levels. Our results stress the importance of including multiple, independent loci in phylogenetic analyses.     

Heteroplasmy and Ancient Translocation of Mitochondrial DNA to the Nucleus in the Chinese Horseshoe Bat (Rhinolophus sinicus) Complex

The utility and reliability of mitochondrial DNA sequences in phylogenetic and phylogeographic studies may be compromised by widespread and undetected nuclear mitochondrial copies (numts) as well as heteroplasmy within individuals. Both numts and heteroplasmy are likely to be common across diverse taxa yet few studies have characterised their frequencies and variation at the intra-specific level. Here we report the presence of both numts and heteroplasmy in the mitochondrial control region of the Chinese horseshoe bat Rhinolophus sinicus. In total we generated 123 sequences from 18 bats, which contained two different numt clades (i.e. Numt-1 and Numt-2) and one mtDNA clade. The sequence divergence between Numt-1 and Numt-2 was 16.8% and each numt type was found in all four R. sinicus taxa, suggesting either two ancient translocations of mitochondrial DNA into the nucleus from the same source taxon, or a single translocation from different source taxa that occurred before the split of R. sinicus into different lineages. Within the mtDNA clade, phylogenetic relationships among the four taxa of R. sinicus were similar to those seen in previous results. Based on PCR comparisons, heteroplasmy was inferred between almost all individuals of R. sinicus with respect to sequence variation. Consistent with introgression of mtDNA between Central sinicus and septentrionalis, individuals from these two taxa exhibited similar signatures of repeated sequences in the control region. Our study highlights the importance of testing for the presence of numts and heteroplasmy when applying mtDNA markers to phylogenetic studies.     

Phylogenetic relationships among Indriidae (Primates,Strepsirhini) inferred from highly repeated DNA band patterns

Comparative studies of highly repeated DNA from different species of Indriidae (Primates, Strepsirhini) allowed confirmation of the specific status of Avahi occidentalis, A. laniger and Propithecus tattersalli. The comparison of their band patterns revealed the existence of specific and common bands from which a cladogram of the family is inferred. This cladogram shows that Avahi clade is the sister-group of Indri and Propithecus clade, and that P. verreauxi is related to P. diadema. These results were discussed in view of those obtained from cytogenetic, morphological and molecular data (mitochondrial DNA). This study shows the capacity of the repeated sequence pattern comparison to be used as a tool for confirming taxa status, (taxinomic classification is a primary determinant of management priorities for endangered species, neglect of distinct taxa may lead to their extinction), and for inferring phylogenetic relationships among related species.     

Origin and diversification of Philippine bulbuls

We examine the origin and diversification of Philippine bulbuls using a phylogenetic framework. Maximum likelihood and Bayesian methods are used to construct trees from DNA sequences of two mitochondrial and two nuclear genes obtained from 11 Philippine bulbul species as well as 32 other Asian and African taxa. The study finds eight independent colonization events of bulbuls to the Philippines, including one clade comprising Philippine members of the genus Ixos that underwent extensive diversification within the archipelago. Each Philippine clade of bulbuls invaded either the Palawan region or the oceanic islands of the Philippines, but not both. Genetic data reveal at least five lineages that warrant recognition as full species. This study underscores how Philippine avian diversity is currently underestimated and highlights the need for further phylogenetic studies in other Philippine bird groups.     

Phylogenetic reconstruction of the South American genus <Emphasis Type="Italic">Leucheria</Emphasis> Lag. (Asteraceae,Nassauvieae) based on nuclear and chloroplast DNA sequences

The genus Leucheria Lag. (Asteraceae Bercht. and J. Presl, tribe Nassauvieae Cass.) comprises 45 species and three infraspecific taxa distributed in the Andean region from southern Chile and Argentina to Peru. Six species are annual herbs. The genus has had a long taxonomic history involving the transference of species described originally under many different genera. The main objectives of this paper were to determine the phylogenetic relationships of species of Leucheria, examine the hypothesis that the ancestor of Leucheria would have originated in a forested habitat and examine the validity of nine morphologically defined evolutionary lines recognized in earlier work on the genus. Additionally we investigated whether the annual species of Leucheria are derived. We extracted DNA from leaf material for 45 taxa (94%) of Leucheria. We used Bayesian inference and plastid and nuclear genes to construct a phylogenetic hypothesis. Results show that Leucheria is monophyletic and is comprised of two main clades. One clade comprises perennial acaulescent/subacaulescent species, all with a solitary capitulum. We recognized three lineages in the second clade comprised of caulescent species that exhibit multiple capitula. Optimization of life-form over the phylogeny showed that five of the six annual species studied are derived in our tree. We conclude that the appearance of the annual habit is associated with the colonization of arid conditions in the winter rainfall coastal desert of northern Chile. Our result shows that species of Leucheria from forested habitats are derived. Discrepancies with previously recognized morphologically defined evolutionary lines were detected.     

Revised classification of former genus Phoxinellus using nuclear DNA sequences

Molecular data inferred from three nuclear DNA regions were used to re-examine the phylogenetic position and taxonomic status of former Phoxinellus taxa. Using either distance method, maximum likelihood or MCMC, phylogenetic tree revealed statistically well supported clade of Delminichthys adspersus, Delminichthys ghetaldii, Delminichthys jadovensis, and Delminichthys krbavensis occupying a sister position to Pelasgus prespensis; furthermore, Phoxinellus pseudalepidotus emerged as a sister taxon to Delminichthys–Pelasgus group. There was a moderate support for sister relationship between Telestes croaticus and Telestes fontinalis, while the position of Telestes metohiensis varied depending on the region and method used. The topology of taxa within Delminichthys was weakly supported and remained pretty much unresolved. Our results confirm a previous notion that the former genus Phoxinellus is not a monophyletic group but rather a grouping of independent lineages.     

Digest: Phylogenetic comparative methods identify traits associated with urbanization tolerance in Anolis*

Humans have, and continue to, dramatically influence the life history of many taxa. Identification of traits that allow taxa to tolerate humans and urban environments is important for informed conservation policy. Winchell et al. (2020) uses a phylogenetic comparative framework to identify such traits in the Caribbean clade of Anolis lizards. They provide an example of how to use disparate data sources to develop probabilities about species’ traits that can be used in phylogenetic analyses.     

Monophyly of clade III nematodes is not supported by phylogenetic analysis of complete mitochondrial genome sequences

Background

The orders Ascaridida, Oxyurida, and Spirurida represent major components of zooparasitic nematode diversity, including many species of veterinary and medical importance. Phylum-wide nematode phylogenetic hypotheses have mainly been based on nuclear rDNA sequences, but more recently complete mitochondrial (mtDNA) gene sequences have provided another source of molecular information to evaluate relationships. Although there is much agreement between nuclear rDNA and mtDNA phylogenies, relationships among certain major clades are different. In this study we report that mtDNA sequences do not support the monophyly of Ascaridida, Oxyurida and Spirurida (clade III) in contrast to results for nuclear rDNA. Results from mtDNA genomes show promise as an additional independently evolving genome for developing phylogenetic hypotheses for nematodes, although substantially increased taxon sampling is needed for enhanced comparative value with nuclear rDNA. Ultimately, topological incongruence (and congruence) between nuclear rDNA and mtDNA phylogenetic hypotheses will need to be tested relative to additional independent loci that provide appropriate levels of resolution.

Results

For this comparative phylogenetic study, we determined the complete mitochondrial genome sequences of three nematode species, Cucullanus robustus (13,972 bp) representing Ascaridida, Wellcomia siamensis (14,128 bp) representing Oxyurida, and Heliconema longissimum (13,610 bp) representing Spirurida. These new sequences were used along with 33 published nematode mitochondrial genomes to investigate phylogenetic relationships among chromadorean orders. Phylogenetic analyses of both nucleotide and amino acid sequence datasets support the hypothesis that Ascaridida is nested within Rhabditida. The position of Oxyurida within Chromadorea varies among analyses; in most analyses this order is sister to the Ascaridida plus Rhabditida clade, with representative Spirurida forming a distinct clade, however, in one case Oxyurida is sister to Spirurida. Ascaridida, Oxyurida, and Spirurida (the sampled clade III taxa) do not form a monophyletic group based on complete mitochondrial DNA sequences. Tree topology tests revealed that constraining clade III taxa to be monophyletic, given the mtDNA datasets analyzed, was a significantly worse result.

Conclusion

The phylogenetic hypotheses from comparative analysis of the complete mitochondrial genome data (analysis of nucleotide and amino acid datasets, and nucleotide data excluding 3^rd positions) indicates that nematodes representing Ascaridida, Oxyurida and Spirurida do not share an exclusive most recent common ancestor, in contrast to published results based on nuclear ribosomal DNA. Overall, mtDNA genome data provides reliable support for nematode relationships that often corroborates findings based on nuclear rDNA. It is anticipated that additional taxonomic sampling will provide a wealth of information on mitochondrial genome evolution and sequence data for developing phylogenetic hypotheses for the phylum Nematoda.

     

Evolution of trnF(GAA) pseudogenes in cruciferous plants

In several studies we used the 5′-trnL(UAA)–trnF(GAA) region of the chloroplast DNA for phylogeographic reconstructions, gene diversity calculations and phylogenetic analyses among the genera Arabidopsis and Boechera. Despite the fact that extensive gene duplications are rare within the chloroplast genome of higher plants, within several genera of the Brassicaceae the anticodon domain of the trnF(GAA) gene exhibit extensive gene duplications with 1–12 tandemly repeated copies in close 5′-proximity of the functional gene. A recent re-examination and additional analysis of trnL(UAA)–trnF(GAA) regions from numerous cruciferous taxa not only reveal extensive trnF gene duplications, but also favour the hypothesis that in cruciferous taxa at least four independent phylogenetic lineages are characterized by these pseudogenes. Among these lineages there is one major clade of taxa carrying pseudogenes indicating an ancient split in crucifer evolution. In two case studies, Boechera and Arabidopsis, intra- and inter-molecular recombinations have been shown to be the reason for the reciprocal exchange of several similar motifs. However, functional constraints might favour two to three or five to six copies as shown for Arabidopsis and Boechera. Herein, we compare the occurrence and distribution of pseudogene copy number in the framework of a comprehensive survey of cpDNA haplotype variation in Boechera, the former genus Cardaminopsis and Arabidopsis thaliana and comment on the value of such kind of mutations in phylogenetic and evolutionary reconstructions.     

Distinct Patterns of Desynchronized Limb Regression in Malagasy Scincine Lizards (Squamata,Scincidae)

Scincine lizards in Madagascar form an endemic clade of about 60 species exhibiting a variety of ecomorphological adaptations. Several subclades have adapted to burrowing and convergently regressed their limbs and eyes, resulting in a variety of partial and completely limbless morphologies among extant taxa. However, patterns of limb regression in these taxa have not been studied in detail. Here we fill this gap in knowledge by providing a phylogenetic analysis of DNA sequences of three mitochondrial and four nuclear gene fragments in an extended sampling of Malagasy skinks, and microtomographic analyses of osteology of various burrowing taxa adapted to sand substrate. Based on our data we propose to (i) consider Sirenoscincus Sakata & Hikida, 2003, as junior synonym of Voeltzkowia Boettger, 1893; (ii) resurrect the genus name Grandidierina Mocquard, 1894, for four species previously included in Voeltzkowia; and (iii) consider Androngo Brygoo, 1982, as junior synonym of Pygomeles Grandidier, 1867. By supporting the clade consisting of the limbless Voeltzkowia mira and the forelimb-only taxa V. mobydick and V. yamagishii, our data indicate that full regression of limbs and eyes occurred in parallel twice in the genus Voeltzkowia (as hitherto defined) that we consider as a sand-swimming ecomorph: in the Voeltzkowia clade sensu stricto the regression first affected the hindlimbs and subsequently the forelimbs, whereas the Grandidierina clade first regressed the forelimbs and subsequently the hindlimbs following the pattern prevalent in squamates. Timetree reconstructions for the Malagasy Scincidae contain a substantial amount of uncertainty due to the absence of suitable primary fossil calibrations. However, our preliminary reconstructions suggest rapid limb regression in Malagasy scincids with an estimated maximal duration of 6 MYr for a complete regression in Paracontias, and 4 and 8 MYr respectively for complete regression of forelimbs in Grandidierina and hindlimbs in Voeltzkowia.     

The molecular phylogeny of aquatic hyphomycetes with affinity to the Leotiomycetes

Aquatic hyphomycetes play a key role in decomposition of submerged organic matter and stream ecosystem functioning. We examined the phylogenetic relationships among various genera of aquatic hyphomycetes belonging to the Leotiomycetes (Ascomycota) using sequences of internal transcribed spacer (ITS) and large subunit (LSU) regions of rDNA generated from 42 pure cultures including 19 ex-types. These new sequence data were analyzed together with additional sequences from 36 aquatic hyphomycetes and 60 related fungi obtained from GenBank. Aquatic hyphomycetes, characterized by their tetraradiate or sigmoid conidia, were scattered in nine supported clades within the Helotiales (Leotiomycetes). Tricladium, Lemonniera, Articulospora, Anguillospora, Varicosporium, Filosporella, and Flagellospora are not monophyletic, with species from the same genus distributed among several major clades. The Gyoerffyella clade and the Hymenoscyphus clade accommodated species from eight and six different genera, respectively. Thirteen aquatic hyphomycete taxa were grouped in the Leotia-Bulgaria clade while twelve species clustered within the Hymenoscyphus clade along with several amphibious ascomycetes. Species of Filosporella and some species from four other aquatic genera were placed in the Ascocoryne-Hydrocina clade. It is evident that many aquatic hyphomycetes have relatives of terrestrial origin. Adaptation to colonize the aquatic environment has evolved independently in multiple phylogenetic lineages within the Leotiomycetes.     

Convoluted history and confusing morphology: Molecular phylogenetic analysis of dicrocoeliids reveals true systematic position of the Anenterotrematidae Yamaguti, 1958 (Platyhelminthes,Digenea)

The Dicrocoeliidae is a highly diverse family of digeneans parasitic in amniotic tetrapods. Detailed molecular phylogenetic analysis of dicrocoeliids is lacking and only a few dicrocoeliids from mammals have been included in previous studies. Sequence data were previously absent for the Anenterotrematidae that shares several morphological characteristics with dicrocoeliids. We examined phylogenetic affinities of several newly sequenced (nuclear 28S rDNA) taxa of dicrocoeliids and anenterotrematids collected from small mammals in Ecuador, Panama, Peru, USA and Vietnam. Our analyses demonstrated that the two anenterotrematid genera (Anenterotrema, Apharyngotrema) belong to the Dicrocoeliidae, placing the Anenterotrematidae into synonymy with the Dicrocoeliidae. Molecular data combined with morphological examination of type and new specimens provided evidence that Parametadelphis and Apharyngotrema are junior synonyms of Metadelphis, with all Metadelphis species lacking a digestive system. Phylogenetic analysis demonstrates that reduction of the alimentary tract in Lutztrema and its loss in Anenterotrema and Metadelphis represent at least two independent evolutionary events. Genera Brachylecithum, Brachydistomum, and Lyperosomum proved to be non-monophyletic, each likely representing more than a single genus. Furthermore, phylogenetic analysis did not support monophyly of the two largest subfamilies of the Dicrocoeliidae (Dicrocoeliinae and Leipertrematinae) with the other two subfamilies not included in this study. Therefore, we propose to abandon the current subfamily division of the Dicrocoeliidae. Analysis of host associations indicates multiple host-switching events throughout evolution of dicrocoeliids. Lastly, analysis of dicrocoeliid geographic distribution revealed that nearly all major clades included taxa from more than a single zoogeographic realm with the exception of the clade Anenterotrema?+?Metadelphis, found only in the Neotropics.     

On the Evolutionary and Biogeographic History of Saxifraga sect. Trachyphyllum (Gaud.) Koch (Saxifragaceae Juss.)

Arctic-alpine plants in the genus Saxifraga L. (Saxifragaceae Juss.) provide an excellent system for investigating the process of diversification in northern regions. Yet, sect. Trachyphyllum (Gaud.) Koch, which is comprised of about 8 to 26 species, has still not been explored by molecular systematists even though taxonomists concur that the section needs to be thoroughly re-examined. Our goals were to use chloroplast trnL-F and nuclear ITS DNA sequence data to circumscribe the section phylogenetically, test models of geographically-based population divergence, and assess the utility of morphological characters in estimating evolutionary relationships. To do so, we sequenced both genetic markers for 19 taxa within the section. The phylogenetic inferences of sect. Trachyphyllum using maximum likelihood and Bayesian analyses showed that the section is polyphyletic, with S. aspera L. and S bryoides L. falling outside the main clade. In addition, the analyses supported several taxonomic re-classifications to prior names. We used two approaches to test biogeographic hypotheses: i) a coalescent approach in Mesquite to test the fit of our reconstructed gene trees to geographically-based models of population divergence and ii) a maximum likelihood inference in Lagrange. These tests uncovered strong support for an origin of the clade in the Southern Rocky Mountains of North America followed by dispersal and divergence episodes across refugia. Finally we adopted a stochastic character mapping approach in SIMMAP to investigate the utility of morphological characters in estimating evolutionary relationships among taxa. We found that few morphological characters were phylogenetically informative and many were misleading. Our molecular analyses provide a foundation for the diversity and evolutionary relationships within sect. Trachyphyllum and hypotheses for better understanding the patterns and processes of divergence in this section, other saxifrages, and plants inhabiting the North Pacific Rim.     

Phylogenetic overview of Erysiphaceae based on nrDNA and MCM7 sequences

The classification system and evolutionary history of Erysiphaceae have been studied based on the results of molecular phylogenetic analyses. However, the sequence data used for these phylogenetic estimations have been limited to the nrDNA of ca., 50 taxa, and the relationships among higher taxonomic groups are not well understood. To provide a phylogenetic overview of Erysiphaceae, we performed phylogenetic estimations based on nrDNA and MCM7 sequences obtained from ca., 270 taxa. The phylogenetic tree showed a similar topology to the trees obtained in previous studies, although the branching order between Golovinomyceteae and Phyllactinieae was different and Phyllactinieae was not monophyletic. Phyllactinieae and Erysipheae were estimated to diversify after the divergence of Golovinomyceteae, suggesting an evolutionary trend in which non-catenate conidia + endoparasitic or non-catenate conidia + ectoparasitic lineages were derived from catenate conidia + ectoparasitic lineages. Phyllactinieae was divided into a clade of Phyllactinia + Leveillula and other clade(s) consisting of Pleochaeta and Queirozia. The phylogenetic hypothesis of Erysiphaceae was updated based on the largest dataset to date, but the higher-level phylogenetic relationships remain unclear. For a more robust phylogenetic hypothesis of Erysiphaceae, further sequence data, including protein coding regions, should be added to the dataset of nrDNA sequences.     

Molecular phylogeny of Ceropegia (Asclepiadoideae, Apocynaceae) from Indian Western Ghats

Ceropegia includes more than 200 species distributed in the Old World ranging from the Canary Islands to Australia. In India, there are about 50 species described on a morphological basis as belonging to Ceropegia, and most of them are endemic to the Western Ghats. To investigate evolutionary relationships among Indian Ceropegia taxa and their allies, a phylogenetic analysis was conducted to include 31 Indian taxa of Ceropegia and Brachystelma and their congeners from other geographical regions using nuclear ribosomal internal transcribed spacer (ITS) and three noncoding chloroplast DNA (cpDNA) sequences, including intergenic spacers trnT-L and trnL-F, and trnL intron. The Western Ghats Ceropegia species were found to be most closely related to Indian Brachystelma, with the two genera being placed sister to each other in the ITS phylogeny or with the Brachystelma clade nested within one of the two subclades of Indian Ceropegia in the cpDNA phylogeny. In contrast, Ceropegia species from other regions and African Brachystelma all formed separate clades basal to the Indian Ceropegia–Brachystelma clade. Thus, it can be concluded that the classical morphology-based delineation of the two genera needs revision to reflect their phylogenetic relationships, which are more in accordance with their geographical origin than with morphology.     

Molecular Phylogeny of the Small Ermine Moth Genus Yponomeuta (Lepidoptera,Yponomeutidae) in the Palaearctic

Background

The small ermine moth genus Yponomeuta (Lepidoptera, Yponomeutidae) contains 76 species that are specialist feeders on hosts from Celastraceae, Rosaceae, Salicaceae, and several other plant families. The genus is a model for studies in the evolution of phytophagous insects and their host-plant associations. Here, we reconstruct the phylogeny to provide a solid framework for these studies, and to obtain insight into the history of host-plant use and the biogeography of the genus.

Methodology/Principal Findings

DNA sequences from an internal transcribed spacer region (ITS-1) and from the 16S rDNA (16S) and cytochrome oxidase (COII) mitochondrial genes were collected from 20–23 (depending on gene) species and two outgroup taxa to reconstruct the phylogeny of the Palaearctic members of this genus. Sequences were analysed using three different phylogenetic methods (parsimony, likelihood, and Bayesian inference).

Conclusions/Significance

Roughly the same patterns are retrieved irrespective of the method used, and they are similar among the three genes. Monophyly is well supported for a clade consisting of the Japanese (but not the Dutch) population of Yponomeuta sedellus and Y. yanagawanus, a Y. kanaiellus–polystictus clade, and a Rosaceae-feeding, western Palaearctic clade (Y. cagnagellus–irrorellus clade). Within these clades, relationships are less well supported, and the patterns between the different gene trees are not so similar. The position of the remaining taxa is also variable among the gene trees and rather weakly supported. The phylogenetic information was used to elucidate patterns of biogeography and resource use. In the Palaearctic, the genus most likely originated in the Far East, feeding on Celastraceae, dispersing to the West concomitant with a shift to Rosaceae and further to Salicaceae. The association of Y. cagnagellus with Euonymus europaeus (Celastraceae), however, is a reversal. The only oligophagous species, Y. padellus, belongs to the derived western Palaearctic clade, evidence that specialisation is reversible.     

The phylogenetic position of the Prolecithophora (Rhabditophora, 'Platyhelminthes')

Complete 18S ribosomal DNA (rDNA) sequences and partial 28S rDNA sequences from a selection of rhabditophoran taxa were obtained and used in combination with literature data to determine the phylogenetic position of the Prolecithophora and of two families sometimes included in the Prolecithophora, the Urastomidae and the Genostomatidae. The results are largely compatible with earlier molecular studies when supported clades are considered, and adjusting for the denser taxonomic sampling of this study. The position of the Proseriata is not compatible with the taxon Seriata, which is rejected. The Rhabdocoela excluding the Fecampiida and the Neodermata is monophyletic. The phylogenetic position of the Neodermata cannot be determined, but its placement is not compatible with the proposed taxa Revertospermata and Mediofusata Kornakova & Joffe, 1999, which are rejected. The Urastomidae and the Genostomatidae in all analyses group with the Fecampiida, and it is our recommendation that these taxa be included in the Fecampiida. The amended Fecampiida always group separately from the Prolecithophora sensu stricto , the Rhabdocoela, and the Neodermata. Our analyses reveal the existence of a strongly supported clade consisting of Prolecithophora + Tricladida + the amended Fecampiida, and we propose the name Adiaphanida for this clade. Tentatively the sister group of the Prolecithophora is a clade consisting of the Tricladida + amended Fecampiida.     

Origin, diversification, and evolution of Samolus valerandi (Samolaceae, Ericales)

The almost cosmopolitan distribution of Samolus valerandi is unique in the genus Samolus L. (Samolaceae), which also includes 12–15 taxa with distributions restricted to smaller areas of the Southern Hemisphere. Recent molecular phylogenetic studies based on chloroplast and nuclear DNA sequences showed that the widespread S. valerandi and the North American S. parviflorus are both part of a strongly supported clade, together with the North American S. vagans, S. spathulatus, and S. latifolius. To better understand the origin, distribution, and diversification of S. valerandi and to clarify the relationships within this clade, we performed molecular phylogenetic analyses based on the plastid trnS-G intergenic spacer and the nuclear ribosomal ITS region. We have also sought further support for relationships by examining flower and leaf characters. On the basis of new results, we propose that S. valerandi, S. parviflorus, and S. vagans are considered as part of a widespread “species complex”, with its centre of diversity in North America. No clear vicariance patterns were found regarding the phylogeography of S. valerandi, which thus seems to have dispersed secondarily to various places around the world, possibly as a result of human activities.     

The tropical African legume Scorodophloeus clade includes two undescribed Hymenostegia segregate genera and Micklethwaitia,a rare,monospecific genus from Mozambique

Legume subfamily Caesalpinioideae accommodates approximately 2250 species in 171 genera which traditionally are placed in four tribes: Caesalpinieae, Cassieae, Cercideae and Detarieae. The monophyletic tribe Detarieae includes the Amherstieae subclade which contains about 55 genera. Our knowledge of the relationships among those genera is good in some cases but for many other genera phylogenetic relationships have been unclear. The non-monophyletic nature of at least two amherstioid genera, Cynometra and Hymenostegia has also complicated the picture. During the course of a multi-disciplinary study of Hymenostegia sensu lato, which includes phylogenetic analyses based on matK and trnL data, we have recovered the “Scorodophloeus clade”, an exclusively tropical African clade of four genera which includes the eponymous genus Scorodophloeus, two undescribed generic segregates of Hymenostegia sensu lato, and the previously unsampled rare monospecific genus Micklethwaitia from Mozambique. Zenkerella is suggested as a possible sister genus to the Scorodophloeus clade. A distribution map is presented of the seven species that belong to the Scorodophloeus clade.