Temporal origins and diversification of Artemisia and allies (Anthemideae, Asteraceae)

Temporal origins and diversification of Artemisia and allies (Anthemideae, Asteraceae).- To assess temporal origins and diversification of lineages within subtribe Artemisiinae and Artemisia group a penalized likelihood analysis was applied on nrDNA ITS and ETS of 63 representatives. The tree was calibrated at the stem node of the Kaschgaria/ Artemisia lineage with the most reliable early Artemisia fossil pollen record from Late Oligocene (23 Ma). The results from this study suggest that the origin of the subtribe goes back to the Late Oligocene (24.6 ± 2.6 Ma) whilst the onset of differentiation of the genus Artemisia and most closely related genera is dated to the Early Miocene (19.8 ± 2.3 Ma). Divergence ages for lineages within the Artemisia group are often between the Early and Middle Miocene, whereas their radiations mostly occurred in the Late Miocene and Pliocene. The temporal context was also used to examine biogeographic and morphological (capitula and pollen type) evolution. Within the Artemisia group all lineages except the North American endemic have colonized the Mediterranean Basin at different epochs from Asian ancestors. Our analyses suggest the divergence of the North American endemic group from Asian ancestors (10.8 ± 1.5 Ma) in the Late Miocene. Homogamous-discoid capitula, characteristic of subgenera Seriphidium and Tridentatae, evolved not only in different geographic regions, but also at different times (2.0 ± 0.8 Ma and 7.9 ± 0.9 Ma respectively) within the Artemisia group. The loss of fertility of central flowers of disciform capitula should be considered as an ancient event in the genus since subgenus Dracunculus is one of the first groups that diverged (17.6 ± 2.1 Ma)

Comparative phylogeography of chloroplast and nuclear DNA markers reveals ancient and present hybridization in the Mediterranean Helichrysum pendulum complex (Compositae)

The geological and climatic history of the Mediterranean basin over the last 6 million years has been determinant in shaping current geographic distribution of genetic variation in organisms. Phylogeographical approaches are considered one of most useful analysis for unraveling the evolutionary history of species. The Helichrysum pendulum complex is a group of three closely related plant species distributed in several islands and isolated continental localities of the Western-Central Mediterranean basin, providing an ideal case of study to analyze the processes involved in modelling its current genetic structure. Two cpDNA region rpl32-trnL intergenic spacer and the nrDNA region ETS were sequenced for 1-8 individuals from each of the 44 total populations sampled, covering the whole geographic range of the complex. Our results suggest that the complex originated in northern Africa and colonized several islands and continental areas of the northern Basin through the Gibraltar and Sicilian straits during phases of low sea level, favored by long distance dispersal events. While ETS data suggest a model of isolation by distance and show a main genetic barrier between populations of Western and Central Mediterranean areas, the rpl32-trnL reveals the existence of two divergent and not geographically structured haplotype groups within the complex. Ancient hybridization events among lineages of sect. Stoechadina are suggested as the most plausible cause for the haplotypes pattern observed, while several evidences of current hybridization between H. pendulum and several species of sect. Stoechadina are also detected in ETS data

Systematics and phylogeography of the Mediterranean Helichysum pendulum complex (Compositae) inferred from nuclear and chloroplast DNA and morphometrics analyses

Multiple factors related to complex geomorphological and climatic history, in addition to biological factors such as hybridization, hinder the definition of some Mediterranean plant groups. The existence of controversial taxonomic treatments, the possible hybridization events involved, and its unknown evolutionary history, make the Helichrysum pendulum complex of H. sect. Stoechadina an ideal model to understand general processes of Mediterranean plant systematics and evolution. The mosaic range of the complex, which is distributed over several islands and continental areas in the western-central Mediterranean Basin, provides an opportunity to investigate how past connections and disconnections between landmasses may have determined the current geographic distribution of genetic variation in this area. The cpDNA region rpl32-trnL intergenic spacer and the nrDNA region ETS were sequenced for 1-8 individuals from each of the 44 populations sampled, covering all taxa and the whole geographic range of the complex. These individuals were analysed together with a broad sampling of the remaining members of sect. Stoechadina. In addition, detailed multivariate analyses of morphological characters were performed for the whole section and for the H. pendulum complex. Considering together distinctive genetic and morphological traits, our species concept is presented and discussed in a context of integrative taxonomy, and five species are recognized within the complex: H. errerae, H. melitense, H. pendulum, H. saxatile and H. valentinum. The first three species are recognizable by qualitative and quantitative morphological traits, and are genetically distinguishable from the rest as shown by the molecular markers analysed. The two last species are reported here to have a putative ancient hybrid origin and are also genetically distinguishable from the rest but morphologically recognisable only by quantitative characters. Phylogenetic relationships shown by nuclear and chloroplast markers, and an intermediate morphology between the two putative parental taxa, point to H. pendulum and H. italicum as the putative parental taxa for H. saxatile, and H. pendulum and H. stoechas as putative parental taxa for H. valentinum. In a discriminant analysis of the five species, 97.8% of all individuals were classified correctly. The high level of haplotype and ribotype diversity observed in North Africa indicates that this region is either the area of origin of the complex or a secondary contact zone. Our results suggest that the complex colonized several islands and migrated through the Gibraltar and Sicilian Straits during phases of low sea level, favoured by local dispersal events that promoted its gradual range expansion. The occurrence of the complex in the Balearic Islands, which have remained isolated even during low sea level phases, could be explained by stochastic long-distance dispersal events

First genome size assessments in Carduncellus and its related genera Femeniasia and Phonus (Asteraceae, Cardueae), with data on 21 taxa

Genome size of 18 species of the genus Carduncellus, two species of the related genus Phonusand the monotypic genus Femeniasia (F. balearica) has been assessed by flow cytometry for the first time. Ploidy levels were assigned using genome size data together with previously reported chromosome counts. A phylogenetic framework was built to visualize how cytogenetic traits distributed across taxa. The results confirmed three ploidy levels (2x, 4x and 6x), with a predominance of diploids. The 2C values ranged from 3.24 pg in Carduncellus calvusto 11.16 pg in C. erio-cephalus, whereas monoploid genome size (1Cx) ranged from 1.29 pg in C. duvauxii (4x)to 2.30 pg in Phonus rhiphaeus (2x). The mean 1Cx for tetraploids was lower than for diploids. For each ploidy level, genome size values of Carduncellus, Femeniasia and Phonus were found to be higher than those of Carthamus. This result is consistent with a trend frequently observed in plants, of higher genome sizes in long life cycle taxa compared to short-lived relative

Crònica (il·lustrada) d’un viatge al paradís: expedició a les Illes Salvatges

Entre l’11 i el 27 de març va tenir lloc l’expedició “Savage Islands Botanical Expedition 2013 – Expedição Botânica Ilhas Selvagens 2013”, que va constituir un dels moments més àlgids i alhora emocionants del projecte “Conservation of the critically endangered endemic flora of the Selvagens Islands, Atlantic Ocean”, finançat per The Mohammed bin Zayed Species Conservation Fund (http://www.speciesconservation.org/). Aquest projecte se centra en l’estudi de tres endemismes exclusius de l’arxipèlag de les Salvatges greument amenaçats, amb l’objectiu final d’implementar mesures efectives per a la seva conservació (vegeu http://www.speciesconservation.org/case‐studies‐projects//1651 per a més informació). Aquests tres endemismes (Euphorbia anachoreta, Asparagus nesiotes subsp. nesiotes i Argyranthemum thalassophilum) compten amb molts pocs efectius (abans de l’expedició s’estimava una mida poblacional inferior a la cinquantena per als dos primers, i de menys de 250 per al darrer) i tenen un gran interès des del punt de vista biogeogràfic atesos l’aïllament de l’arxipèlag (el territori terrestre més proper són les Illes Canàries, situades a uns 165 quilòmetres al sud) i la seva antiguitat geològica (prop de 30 milions d’anys, essent l’arxipèlag més antic de tota la Macaronèsia; Geldmacher et al., 2001)

Crònica (il·lustrada) d’un viatge al paradís: expedició a les Illes Salvatges

Entre l’11 i el 27 de març va tenir lloc l’expedició “Savage Islands Botanical Expedition 2013 – Expedição Botânica Ilhas Selvagens 2013”, que va constituir un dels moments més àlgids i alhora emocionants del projecte “Conservation of the critically endangered endemic flora of the Selvagens Islands, Atlantic Ocean”, finançat per The Mohammed bin Zayed Species Conservation Fund (http://www.speciesconservation.org/). Aquest projecte se centra en l’estudi de tres endemismes exclusius de l’arxipèlag de les Salvatges greument amenaçats, amb l’objectiu final d’implementar mesures efectives per a la seva conservació (vegeu http://www.speciesconservation.org/case‐studies‐projects//1651 per a més informació). Aquests tres endemismes (Euphorbia anachoreta, Asparagus nesiotes subsp. nesiotes i Argyranthemum thalassophilum) compten amb molts pocs efectius (abans de l’expedició s’estimava una mida poblacional inferior a la cinquantena per als dos primers, i de menys de 250 per al darrer) i tenen un gran interès des del punt de vista biogeogràfic atesos l’aïllament de l’arxipèlag (el territori terrestre més proper són les Illes Canàries, situades a uns 165 quilòmetres al sud) i la seva antiguitat geològica (prop de 30 milions d’anys, essent l’arxipèlag més antic de tota la Macaronèsia; Geldmacher et al., 2001)

Temporal origins and diversification of Artemisia and allies (Anthemideae, Asteraceae)

Temporal origins and diversification of Artemisia and allies (Anthemideae, Asteraceae).- To assess temporal origins and diversification of lineages within subtribe Artemisiinae and Artemisia group a penalized likelihood analysis was applied on nrDNA ITS and ETS of 63 representatives. The tree was calibrated at the stem node of the Kaschgaria/ Artemisia lineage with the most reliable early Artemisia fossil pollen record from Late Oligocene (23 Ma). The results from this study suggest that the origin of the subtribe goes back to the Late Oligocene (24.6 ± 2.6 Ma) whilst the onset of differentiation of the genus Artemisia and most closely related genera is dated to the Early Miocene (19.8 ± 2.3 Ma). Divergence ages for lineages within the Artemisia group are often between the Early and Middle Miocene, whereas their radiations mostly occurred in the Late Miocene and Pliocene. The temporal context was also used to examine biogeographic and morphological (capitula and pollen type) evolution. Within the Artemisia group all lineages except the North American endemic have colonized the Mediterranean Basin at different epochs from Asian ancestors. Our analyses suggest the divergence of the North American endemic group from Asian ancestors (10.8 ± 1.5 Ma) in the Late Miocene. Homogamous-discoid capitula, characteristic of subgenera Seriphidium and Tridentatae, evolved not only in different geographic regions, but also at different times (2.0 ± 0.8 Ma and 7.9 ± 0.9 Ma respectively) within the Artemisia group. The loss of fertility of central flowers of disciform capitula should be considered as an ancient event in the genus since subgenus Dracunculus is one of the first groups that diverged (17.6 ± 2.1 Ma)

Comparative phylogeography of chloroplast and nuclear DNA markers reveals ancient and present hybridization in the Mediterranean Helichrysum pendulum complex (Compositae)

The geological and climatic history of the Mediterranean basin over the last 6 million years has been determinant in shaping current geographic distribution of genetic variation in organisms. Phylogeographical approaches are considered one of most useful analysis for unraveling the evolutionary history of species. The Helichrysum pendulum complex is a group of three closely related plant species distributed in several islands and isolated continental localities of the Western-Central Mediterranean basin, providing an ideal case of study to analyze the processes involved in modelling its current genetic structure. Two cpDNA region rpl32-trnL intergenic spacer and the nrDNA region ETS were sequenced for 1-8 individuals from each of the 44 total populations sampled, covering the whole geographic range of the complex. Our results suggest that the complex originated in northern Africa and colonized several islands and continental areas of the northern Basin through the Gibraltar and Sicilian straits during phases of low sea level, favored by long distance dispersal events. While ETS data suggest a model of isolation by distance and show a main genetic barrier between populations of Western and Central Mediterranean areas, the rpl32-trnL reveals the existence of two divergent and not geographically structured haplotype groups within the complex. Ancient hybridization events among lineages of sect. Stoechadina are suggested as the most plausible cause for the haplotypes pattern observed, while several evidences of current hybridization between H. pendulum and several species of sect. Stoechadina are also detected in ETS data