Search

Understanding the spatial and temporal frameworks of species diversification is fundamental in evolutionary biology. Assessing the geographic origin and dispersal history of highly diverse lineages of rapid diversification can be hindered by the lack of appropriately sampled, resolved, and strongly supported phylogenetic contexts. The use of currently available cost-efficient sequencing strategies allows for the generation of a substantial amount of sequence data for dense taxonomic samplings, which together with well-curated geographic information and biogeographic models allow us to formally test the mode and tempo of dispersal events occurring in quick succession. Here, we assess the spatial and temporal frameworks for the origin and dispersal history of the expanded clade K, a highly diverse Tillandsia subgenus Tillandsia (Bromeliaceae, Poales) lineage hypothesized to have undergone a rapid radiation across the Neotropics. We assembled full plastomes from Hyb-Seq data for a dense taxon sampling of the expanded clade K plus a careful selection of outgroup species and used them to estimate a time- calibrated phylogenetic framework. This dated phylogenetic hypothesis was then used to perform biogeographic model tests and ancestral area reconstructions based on a comprehensive compilation of geographic information. The expanded clade K colonized North and Central America, specifically the Mexican transition zone and the Mesoamerican dominion, by long-distance dispersal from South America at least 4.86 Mya, when most of the Mexican highlands were already formed. Several dispersal events occurred subsequently northward to the southern Nearctic region, eastward to the Caribbean, and southward to the Pacific dominion during the last 2.8 Mya, a period characterized by pronounced climate fluctuations, derived from glacial--interglacial climate oscillations, and substantial volcanic activity, mainly in the Trans-Mexican Volcanic Belt. Our taxon sampling design allowed us to calibrate for the first time several nodes, not only within the expanded clade K focal group but also in other Tillandsioideae lineages. We expect that this dated phylogenetic framework will facilitate future macroevolutionary studies and provide reference age estimates to perform secondary calibrations for other Tillandsioideae lineages. [ABSTRACT FROM AUTHOR]

The highly variable tufted hairgrass Deschampsia cespitosa is a tussock-forming plant especially of cool and humid environments. Although common and widespread, its phylogeographic structure and the significance of polyploidy for its evolution are poorly understood. Here we used a phylogenomic approach to study the genetic structure of this species in Europe and how the polyploid cytotypes/subspecies are related to the diploids. Using genomic data (RADseq and whole plastid sequencing) we found a highly divergent Iberian group, including the Spanish Deschampsia cespitosa subsp. cespitosa (diploid and tetraploid) and the Macaronesian island endemic diploid Deschampsia argentea. Moreover, we found substantial divergence of pseudoviviparous tetraploids (Deschampsia cespitosa subspp. neoalpina and rhenana) from seminiferous tetraploids (except Deschampsia cespitosa subsp. littoralis) and all diploids of the remaining European samples. The divergent pseudoviviparous tetraploids (D. cespitosa subspp. neoalpina and rhenana) and the seminiferous tetraploid D. cespitosa subsp. littoralis probably represent periglacial and relict lineages of unknown origin regarding auto- and/or allo-polyploidy, whereas other seminiferous tetraploid variants of D. cespitosa are always nested in the diploid D. cespitosa , suggesting multiple autopolyploid origins. An analysis after excluding the Iberian Group and the highly divergent tetraploids revealed five genetic groups with overlapping geographical patterns. However, the recovered geographical structure, the overall low genetic divergence and the diffuse genetic structure point to recolonization from various refugial areas and secondary contact. Effective wind dispersal of pollen and seeds in an open early post-glacial tundra landscape and, finally, increasing human impact on dispersal of this grass since the Neolithic, may have enhanced admixture and resulted in the complex patterns detected today. [ABSTRACT FROM AUTHOR]

The goal of this study was to tackle two questions related to the systematics of small-flowering Euphrasia species from the Eastern Alps. Our first aim was to test the hypothesis of a wider distribution of diploid E. inopinata, considered endemic to the uppermost Ötztal valley in Austria based on ploidy screening of ca. 70 populations along a latitudinal transect. We failed to find new populations of E. inopinata but during the sampling campaign, a diploid population was detected in the eastern Ortler/Ortles mountain range (Italy), which could neither be assigned to E. inopinata nor to E. minima. Thus, our second aim was to clarify, based on a comprehensive sampling of individuals and the use of Amplified Fragment Length Polymorphisms (AFLPs) and/or morphometric data, if this diploid population is morphologically and genetically consistently divergent from both, tetraploid widespread E. minima and E. inopinata. As this was confirmed, we established the relationships of the new entity based on Internal Transcribed Spacer sequences, which uncovered a close relationship with E. minima and describe it here as a new diploid species, E. ultima, which, based on current knowledge, is locally endemic even if a bigger distribution area appears likely. [ABSTRACT FROM AUTHOR]

Copyright of Molecular Ecology Resources is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Subtribe Vrieseinae comprise four genera, Alcantarea , Stigmatodon , Vriesea s.s. and Waltillia , encompassing c. 20% of species in Tillandsioideae (Bromeliaceae), almost all of which are exclusive to Brazil. Here, we explore the biogeographic history of Vrieseinae, sampling 21 of the 22 genera of Tillandsioideae (130 terminals) and three DNA sequence markers (two plastid: rps16-trnK and matK ; one nuclear: PHYC). We inferred a dated phylogeny and the ancestral areas of this lineage through RASP (reconstruct ancestral state in phylogeny) analyses. Vrieseinae were recovered as monophyletic, but tribe Vrieseeae (subtribe Vrieseinae + subtribe Cipuropsidinae) were not. A vicariant event between the Andes and Brazilian Shield probably occurred c. 10 Mya, when two clades, Cipuropsidineae + Tillandsieae and Vrieseineae, diverged. The Atlantic Forest plus the Chacoan region is recognized as the ancestral area for Vrieseinae. The results confirmed the recent origin of genera of Vrieseinae, with estimated crown ages in the Pliocene (5.3–2.6 Mya). We propose that the Paranaean Sea influenced the divergence of the main clades; Pleistocene events were probably responsible for the diversification of the most recent clades. This study sheds light on the biogeographic history of a key group of Neotropical plants, providing a new hypothesis for the evolution of bromeliads. [ABSTRACT FROM AUTHOR]

In this review article, we provide an overview of the status of research on Old World Ebenaceae with an emphasis on the large genus Diospyros. The well-supported phylogenetic tree obtained from nucleotide sequences of multiple regions of plastid genome gave clear insights into the subfamilial classification of Ebenaceae. It supported inclusion of previously recognized genera such as Cargillia, Gunisanthus, Maba, Macreightia and Tetraclis in Diospyros. Endemic Diospyros spp. of New Caledonia have multiple origins. One of these clades has c. 21 species that are morphologically distinct and occupy different ecological niches, but they exhibit low genetic variation, leading to a lack of phylogenetic resolution. Analyses of whole plastid genome sequences did not greatly increase resolution or support for results of our previous plastid analyses. Geographical clustering of the individuals against a background of lower sequence divergence of the whole plastid genome could be due to transfer of plastid genomes during hybridization and introgression following secondary contact. However, > 8400 filtered single nucleotide polymorphisms (SNPs) from restriction site associated DNA sequencing (RADseq) confirmed species circumscriptions for this clade and produced well-supported phylogenetic relationships, pointing to an early regional clustering among populations and species. This supported allopatric speciation with respect to macrohabitat (i.e. climatic conditions) having had a role in the initial differentiation in the group. A later, more rapid radiation involved divergence with respect to microhabitat (e.g. soil preference). Although chromosome counts indicate that Diospyros spp. are consistently diploids with 2 n = 30, extensive variation in genome size has been observed, which is due to an increase of repeat elements, including LTR/gypsy. In Ebenaceae, pollen is heterogeneous, and palynological synapomorphies are traced at different taxonomic levels. Several new Diospyros spp. have recently been identified and documented from India, Thailand, China, Africa and New Caledonia. Taxonomic revisions have been completed for the Australian species, and synonyms are reported for some New Caledonian Diospyros spp. [ABSTRACT FROM AUTHOR]

Background and Aims Capsicum (Solanaceae), native to the tropical and temperate Americas, comprises the well-known sweet and hot chili peppers and several wild species. So far, only partial taxonomic and phylogenetic analyses have been done for the genus. Here, the phylogenetic relationships between nearly all taxa of Capsicum were explored to test the monophyly of the genus and to obtain a better knowledge of species relationships, diversification and expansion. Methods Thirty-four of approximately 35 Capsicum species were sampled. Maximum parsimony and Bayesian inference analyses were performed using two plastid markers (matK and psbA-trnH) and one single-copy nuclear gene (waxy). The evolutionary changes of nine key features were reconstructed following the parsimony ancestral states method. Ancestral areas were reconstructed through a Bayesian Markov chain Monte Carlo analysis. Key Results Capsicum forms a monophyletic clade, with Lycianthes as a sister group, following both phylogenetic approaches. Eleven well-supported clades (four of them monotypic) can be recognized within Capsicum, although some interspecific relationships need further analysis. A few features are useful to characterize different clades (e.g. fruit anatomy, chromosome base number), whereas some others are highly homoplastic (e.g. seed colour). The origin of Capsicum is postulated in an area along the Andes of western to north-western South America. The expansion of the genus has followed a clockwise direction around the Amazon basin, towards central and south-eastern Brazil, then back to western South America, and finally northwards to Central America. Conclusions New insights are provided regarding interspecific relationships, character evolution, and geographical origin and expansion of Capsicum. A clearly distinct early-diverging clade can be distinguished, centred in western-north-western South America. Subsequent rapid speciation has led to the origin of the remaining clades. The diversification of Capsicum has culminated in the origin of the main cultivated species in several regions of South to Central America. [ABSTRACT FROM AUTHOR]

We studied the genetic diversity and structure of the Tillandsia capillaris complex, a morphologically diverse group of highly specialized epiphytes, across the distribution range in arid mountain regions of central Peru, Chile, Bolivia and central Argentina. To elucidate the phylogenetic relationships in the complex and to explore the taxon boundaries among populations, we used three plastid markers ( rpoB-trnC-petN, trnK-matK-trnK, ycf1, c. 8100 bp in total) and one single-copy nuclear gene ( PHYC, c. 1200 bp) for 69 populations and 96 individuals of the T. capillaris complex plus 16 outgroup taxa. Bayesian inference of plastid DNA data indicates the existence of two evolutionary core lineages, which can be recognized as two distinct species: T. capillaris and T. virescens (as proposed previously on the basis of morphological characters). Tillandsia capillaris is a monophyletic and homogeneous group, widely distributed and less genetically variable, whereas T. virescens (including T. kuehhasii) is genetically more divergent with most of the forms growing at high elevation in arid areas, except for the small clade including T. virescens s.s. (= T. cordobensis), which grows in lower, more humid habitats. The nuclear analysis resulted in a polytomy with some individuals showing incongruent positions between plastid and nuclear topologies. The high haplotype diversity, consisting of 63 plastid DNA haplotypes in 69 populations, was resolved as two core lineages occurring from north to south, allowing us to establish a preliminary view of the genetic variation overlapping between the two taxa. The results suggest that the genetic differentiation into two main clades is consistent with morphological variation in this Andean complex. [ABSTRACT FROM AUTHOR]

We performed a phylogenetic analysis using maximum parsimony and Bayesian inference of three plastid DNA markers and the external transcribed spacer ( ETS) of nuclear ribosomal DNA to assess the species composition of the Tillandsia utriculata complex and their phylogenetic relationships, and to reconstruct patterns of character evolution and biogeography. The results showed that species of the T. utriculata complex are nested in a clade composed mainly of Mexican and Central American species of T. subgenus Tillandsia (Mexican Clade), and are organized in two lineages: the T. utriculata clade and the T. limbata clade. The ancestor of the core Mexican Clade was probably a T. utriculata-like epiphyte (Group II-type remote flowers and flexuous rachises). The T. utriculata clade is defined morphologically by the presence of acute petals. In this clade, there are two lineages: one of high-elevation, saxicolous, grey-leaved plants from the Mexican Plateau; and one which is more widespread and found from the Gulf of Mexico to Venezuela. The T. limbata clade probably arose in western Mesoamerica and is defined by rounded petals. These species are found mainly in tropical dry forests, but one species colonized wet environments of eastern Mesoamerica. Finally, analyses based on the ETS region allowed us to distinguish between T. utriculata and T. pringlei. [ABSTRACT FROM AUTHOR]

The article introduces Tillandsia lechneri, a new epilithic Tillandsia from Central Bolivia, named after Peter Lechner of the Agricultural University in Vienna, Austria who observed the plant during a botanical field trip in September 2007. It notes differences from its close relatives T. lotteae and T. xiphioides in terms of floral bract color, sepal and petal lengths, and scent. A diagram showing the maximum likelihood phylogram containing T. lechneri and its relatives is presented.

The article discusses a study on the Tillandsia L., the largest genus of Bromeliaceae with more than 620 pieces in six subgenera ranging from Southeastern U.S. to subtropical Argentine and Chile inhabiting tropical rainforests and deserts from the lowlands to the highlands. It aims to elucidate the aspects belonging to Tillandsia subs. Tillandsia and the phylogenetic relationships of taxa within the subgenus. Variation and information within 8 plastid DNA markers were assessed.

Background: The unbranched filamentous green alga Spirogyra (Streptophyta, Zygnemataceae) is easily recognizable based on its vegetative morphology, which shows one to several spiral chloroplasts. This simple structure falsely points to a low genetic diversity: Spirogyra is commonly excluded from phylogenetic analyses because the genus is known as a long-branch taxon caused by a high evolutionary rate. Results: We focused on this genetic diversity and sequenced 130 Spirogyra small subunit nuclear ribosomal DNA (SSU rDNA) strands of different origin. The resulting SSU rDNA sequences were used for phylogenetic analyses using complex evolutionary models (posterior probability, maximum likelihood, neighbor joining, and maximum parsimony methods). The sequences were between 1672 and 1779 nucleotides long. Sequence comparisons revealed 53 individual clones, but our results still support monophyly of the genus. Our data set did not contain a single slow-evolving taxon that would have been placed on a shorter branch compared to the remaining sequences. Out of 130 accessions analyzed, 72 showed a secondary loss of the 1506 group I intron, which formed a long-branched group within the genus. The phylogenetic relationship to the genus Spirotaenia was not resolved satisfactorily. The genetic distance within the genus Spirogyra exceeded the distances measured within any other genus of the remaining Zygnemataceae included in this study. Conclusion: Overall, we define eight distinct clades of Spirogyra, one of them including the genus Sirogonium. A large number of non-homoplasious synapomorphies (NHS; 114 NHS in total) was found for Spirogyra (41 NHS) and for each clade (totaling 73 NHS). This emphasizes the high genetic diversity of this genus and the distance to the remaining Zygnematophyceae. [ABSTRACT FROM AUTHOR]

* Premise of the study: The South American genus Gymnocalycium (Cactoideae-Trichocereae) demonstrates how the sole use of morphological data in Cactaceae results in conflicts in assessing phylogeny, constructing a taxonomic system, and analyzing trends in the evolution of the genus. * Methods: Molecular phylogenetic analysis was performed using parsimony and Bayesian methods on a 6195-bp data matrix of plastid DNA sequences (atpl-atpH, petL-psbE, trnK-matK, trnT-trnL-trnF) of 78 samples, including 52 species and infraspecific taxa representing all the subgenera of Gymnocalycium. We assessed morphological character evolution using likelihood methods to optimize characters on a Bayesian tree and to reconstruct possible ancestral states. * Key results: The results of the phylogenetic study confirm the monophyly of the genus, while supporting overall the available infrageneric classification based on seed morphology. Analysis showed the subgenera Microsemineum and Macrosemineum to be polyphyletic and paraphyletic. Analysis of morphological characters showed a tendency toward reduction of stem size, reduction in quantity and hardiness of spines, increment of seed size, development of napiform roots, and change from juicy and colorful fruits to dry and green fruits. * Conclusions: Gymnocalycium saglionis is the only species of Microsemineum and a new name is required to identify the clade including the remaining species of Microsemineum: we propose the name Scabrosemineum in agreement with seed morphology. Identifying morphological trends and environmental features allows for a better understanding of the events that might have influenced the diversification of the genus. [ABSTRACT FROM AUTHOR]