Aggiornamenti e novità sulle conoscenze di Pancratium maritimum (Amaryllidaceae)

Pancratium maritimum L., bulbosa perenne degli ambienti dunali costieri, è un taxon relativamente recente se comparato con le specie del genere a gravitazione mediterranea. Gli studi noti su questa specie hanno analizzato vari aspetti della biologia (riproduttivi, biochimici, filogenetici, genetici, ecc.). Tuttavia, esistono ancora lacune scientifiche, tra cui l’assenza di studi su ampio areale di genetica di conservazione e sugli adattamenti eco-morfofisiologici alle condizioni di stress. Per ampliare le conoscenze su P. maritimum, la Fondazione Nando Peretti nel novembre 2012 ha finanziato un progetto triennale sulla conoscenza e la salvaguardia di questa specie (Progetto 2012-83). In questo contributo si presentano i risultati ottenuti per le diverse linee di ricerca finora affrontate, che vanno dalle analisi ad ampio areale dei popolamenti, usando un approccio sia genetico che GIS, alla caratterizzazione morfologica e eco-fisiologica di varie popolazioni

Phylogeography of a Land Snail Suggests Trans-Mediterranean Neolithic Transport

Background: Fragmented distribution ranges of species with little active dispersal capacity raise the question about their place of origin and the processes and timing of either range fragmentation or dispersal. The peculiar distribution of the land snail Tudorella sulcata s. str. in Southern France, Sardinia and Algeria is such a challenging case. Methodology: Statistical phylogeographic analyses with mitochondrial COI and nuclear hsp70 haplotypes were used to answer the questions of the species' origin, sequence and timing of dispersal. The origin of the species was on Sardinia. Starting from there, a first expansion to Algeria and then to France took place. Abiotic and zoochorous dispersal could be excluded by considering the species' life style, leaving only anthropogenic translocation as parsimonious explanation. The geographic expansion could be dated to approximately 8,000 years before present with a 95% confidence interval of 10,000 to 3,000 years before present. Conclusions: This period coincides with the Neolithic expansion in the Western Mediterranean, suggesting a role of these settlers as vectors. Our findings thus propose that non-domesticated animals and plants may give hints on the direction and timing of early human expansion routes

Universal Artifacts Affect the Branching of Phylogenetic Trees, Not Universal Scaling Laws

The superficial resemblance of phylogenetic trees to other branching structures allows searching for macroevolutionary patterns. However, such trees are just statistical inferences of particular historical events. Recent meta-analyses report finding regularities in the branching pattern of phylogenetic trees. But is this supported by evidence, or are such regularities just methodological artifacts? If so, is there any signal in a phylogeny?In order to evaluate the impact of polytomies and imbalance on tree shape, the distribution of all binary and polytomic trees of up to 7 taxa was assessed in tree-shape space. The relationship between the proportion of outgroups and the amount of imbalance introduced with them was assessed applying four different tree-building methods to 100 combinations from a set of 10 ingroup and 9 outgroup species, and performing covariance analyses. The relevance of this analysis was explored taking 61 published phylogenies, based on nucleic acid sequences and involving various taxa, taxonomic levels, and tree-building methods.All methods of phylogenetic inference are quite sensitive to the artifacts introduced by outgroups. However, published phylogenies appear to be subject to a rather effective, albeit rather intuitive control against such artifacts. The data and methods used to build phylogenetic trees are varied, so any meta-analysis is subject to pitfalls due to their uneven intrinsic merits, which translate into artifacts in tree shape. The binary branching pattern is an imposition of methods, and seldom reflects true relationships in intraspecific analyses, yielding artifactual polytomies in short trees. Above the species level, the departure of real trees from simplistic random models is caused at least by two natural factors--uneven speciation and extinction rates; and artifacts such as choice of taxa included in the analysis, and imbalance introduced by outgroups and basal paraphyletic taxa. This artifactual imbalance accounts for tree shape convergence of large trees.There is no evidence for any universal scaling in the tree of life. Instead, there is a need for improved methods of tree analysis that can be used to discriminate the noise due to outgroups from the phylogenetic signal within the taxon of interest, and to evaluate realistic models of evolution, correcting the retrospective perspective and explicitly recognizing extinction as a driving force. Artifacts are pervasive, and can only be overcome through understanding the structure and biological meaning of phylogenetic trees. Catalan Abstract in Translation S1

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

Euro+Med-Checklist Notulae, 11

This is the eleventh of a series of miscellaneous contributions, by various authors, where hitherto unpublished data relevant to both the Med-Checklist and the Euro+Med (or Sisyphus) projects are presented. This instalment deals with the families Anacardiaceae, Asparagaceae (incl. Hyacinthaceae), Bignoniaceae, Cactaceae, Compositae, Cruciferae, Cyperaceae, Ericaceae, Gramineae, Labiatae, Leguminosae, Orobanchaceae, Polygonaceae, Rosaceae, Solanaceae and Staphyleaceae. It includes new country and area records and taxonomic and distributional considerations for taxa in Bidens, Campsis, Centaurea, Cyperus, Drymocallis, Erigeron, Hoffmannseggia, Hypopitys, Lavandula, Lithraea, Melilotus, Nicotiana, Olimarabidopsis, Opuntia, Orobanche, Phelipanche, Phragmites, Rumex, Salvia, Schinus, Staphylea, and a new combination in Drimia. Citation For the whole article: Raab-Straube E. von & Raus Th. (ed.) 2019: Euro+Med-Checklist Notulae, 11 [Notulae ad floram euro-mediterraneam pertinentes No. 40]. - Willdenowia 49: 421-445. doi: https://doi.org/10.3372/wi.49.49312 For a single contribution (example): Strid A. 2019: Bidens alba (L.) DC. - Pp. 424-426 in: Raab-Straube E. von & Raus Th. (ed.), Euro+Med-Checklist Notulae, 11 [Notulae ad floram euro-mediterraneam pertinentes No. 40]. - Willdenowia 49: 421-445. doi: https://doi.org/10.3372/wi.49.49312 Version of record first published online on 6 December 2019 ahead of inclusion in December 2019 issue. © 2019 The Authors