Historical Isolation versus Recent Long-Distance Connections between Europe and Africa in Bifid Toadflaxes (Linaria sect. Versicolores)

Background: Due to its complex, dynamic and well-known paleogeography, the Mediterranean region provides an ideal framework to study the colonization history of plant lineages. The genus Linaria has its diversity centre in the Mediterranean region, both in Europe and Africa. The last land connection between both continental plates occurred during the Messinian Salinity Crisis, in the late Miocene (5.96 to 5.33 Ma). Methodology/Principal Findings: We analyzed the colonization history of Linaria sect. Versicolores (bifid toadflaxes), which includes c. 22 species distributed across the Mediterranean, including Europe and Africa. Two cpDNA regions (rpl32-trnL UAG and trnK-matK) were sequenced from 66 samples of Linaria. We conducted phylogenetic, dating, biogeographic and phylogeographic analyses to reconstruct colonization patterns in space and time. Four major clades were found: two of them exclusively contain Iberian samples, while the other two include northern African samples together with some European samples. The bifid toadflaxes have been split in African and European clades since the late Miocene, and most lineage and speciation differentiation occurred during the Pliocene and Quaternary. We have strongly inferred four events of post-Messinian colonization following long-distance dispersal from northern Africa to the Iberian Peninsula, Sicily and Greece. Conclusions/Significance: The current distribution of Linaria sect. Versicolores lineages is explained by both ancien

Adaptive Radiation in Mediterranean Cistus (Cistaceae)

lineage consists of 12 species primarily distributed in Mediterranean habitats and is herein subject to analysis. lineages), which display asymmetric characteristics: number of species (2 vs. 10), leaf morphologies (linear vs. linear to ovate), floral characteristics (small, three-sepalled vs. small to large, three- or five-sepalled flowers) and ecological attributes (low-land vs. low-land to mountain environments). A positive phenotype-environment correlation has been detected by historical reconstructions of morphological traits (leaf shape, leaf labdanum content and leaf pubescence). Ecological evidence indicates that modifications of leaf shape and size, coupled with differences in labdanum secretion and pubescence density, appear to be related to success of new species in different Mediterranean habitats.

Body Shape and Life Style of the Extinct Balearic Dormouse Hypnomys (Rodentia, Gliridae): New Evidence from the Study of Associated Skeletons

Hypnomys is a genus of Gliridae (Rodentia) that occurred in the Balearic Islands until Late Holocene. Recent finding of a complete skeleton of the chronospecies H. morpheus (Late Pleistocene-Early Holocene) and two articulated skeletons of H. cf. onicensis (Late Pliocene) allowed the inference of body size and the calculation of several postcranial indexes. We also performed a Factorial Discriminant Analysis (FDA) in order to evaluate locomotory behaviour and body shape of the taxa. Using allometric models based on skull and tooth measurements, we calculated a body weight between 173 and 284 g for H. morpheus, and direct measurements of articulated skeletons yielded a Head and Body Length (HBL) of 179 mm and a Total Body Length of 295 mm for this species. In addition to the generally higher robustness of postcranial bones already recorded by previous authors, H. morpheus, similar to Canariomys tamarani, another extinct island species, displayed elongated zygopodium bones of the limbs and a wider distal humerus and femur than in an extant related taxon, Eliomys quercinus. Indexes indicated that Hypnomys was more terrestrial and had greater fossorial abilities than E. quercinus. This was also corroborated by a Discriminant Analysis, although no clear additional inference of locomotory abilities could be calculated

Mediterranean-climate streams and rivers: geographically separated but ecologically comparable freshwater systems

Streams and rivers in mediterranean-climate regions (med-rivers in med-regions) are ecologically unique, with flow regimes reflecting precipitation patterns. Although timing of drying and flooding is predictable, seasonal and annual intensity of these events is not. Sequential flooding and drying, coupled with anthropogenic influences make these med-rivers among the most stressed riverine habitat worldwide. Med-rivers are hotspots for biodiversity in all med-regions. Species in med-rivers require different, often opposing adaptive mechanisms to survive drought and flood conditions or recover from them. Thus, metacommunities undergo seasonal differences, reflecting cycles of river fragmentation and connectivity, which also affect ecosystem functioning. River conservation and management is challenging, and trade-offs between environmental and human uses are complex, especially under future climate change scenarios. This overview of a Special Issue on med-rivers synthesizes information presented in 21 articles covering the five med-regions worldwide: Mediterranean Basin, coastal California, central Chile, Cape region of South Africa, and southwest and southern Australia. Research programs to increase basic knowledge in less-developed med-regions should be prioritized to achieve increased abilities to better manage med-rivers

Coalescent Simulations Reveal Hybridization and Incomplete Lineage Sorting in Mediterranean Linaria

We examined the phylogenetic history of Linaria with special emphasis on the Mediterranean sect. Supinae (44 species). We revealed extensive highly supported incongruence among two nuclear (ITS, AGT1) and two plastid regions (rpl32-trnLUAG, trnS-trnG). Coalescent simulations, a hybrid detection test and species tree inference in *BEAST revealed that incomplete lineage sorting and hybridization may both be responsible for the incongruent pattern observed. Additionally, we present a multilabelled *BEAST species tree as an alternative approach that allows the possibility of observing multiple placements in the species tree for the same taxa. That permitted the incorporation of processes such as hybridization within the tree while not violating the assumptions of the *BEAST model. This methodology is presented as a functional tool to disclose the evolutionary history of species complexes that have experienced both hybridization and incomplete lineage sorting. The drastic climatic events that have occurred in the Mediterranean since the late Miocene, including the Quaternary-type climatic oscillations, may have made both processes highly recurrent in the Mediterranean flora

Pollen Record of the Saint-macaire Maar (herault, Southern France) - a Lower Pleistocene Glacial Phase in the Languedoc Coastal-plain

The age of the Saint-Macaire maar sediment, in the northwest Mediterranean coastal plain, is between 1.4 and about 0.7 Ma. The pollen diagrams indicate an open xeric vegetation (steppe). The moderate percentages of thermophilous trees support the hypothesis of vegetation refugia along the north Mediterranean shoreline as far back as Early Pleistocene

A method for climatic reconstruction of the Mediterranean Pliocene using pollen data

International audiencePollen data from numerous sites around the Mediterranean Sea indicate that several important vegetation and climatic changes occurred during the Pliocene. These data are in good agreement with pollen records from northwest Europe and with delta(18)O curves from Mediterranean and Atlantic deep-sea cores. Quantitative palaeoclimatic reconstructions from Pliocene pollen data of the Mediterranean region cannot be based on conventional modem analogue techniques, as individual Pliocene pollen spectra contain taxa representing temperate, warm-temperate and subtropical plants that do not grow together today. instead, we propose a new method that uses a climatic amplitude method modified to take partially into account the relative abundances of the taxa. We applied this method to the Pliocene Garraf 1 palynological sequence from Catalonia, which provides a long continuous record of climatic change from 5.3 Ma to the Early Pleistocene. We estimate that annual temperatures were 1 to 5 degrees C higher than today and the annual precipitation 400 to 1000 mm higher than today prior to the beginning of the late Cenozoic glacial-interglacial cycles. in contrast, temperature and precipitation both fell sharply during the glacial phases of the earliest glacial-interglacial cycles. (C) 1998 Elsevier Science B.V. All rights reserved

Bioclimatic signification of marker taxa of the Mediterranean Pliocene

International audienceThe climatic reconstruction of the Pliocene, based on pollen data, requires a new method of quantification because of the presence in pollen spectra, of temperate, warm-temperate but also subtropical plants. As no modern pollen spectra contain all these taxa, the best analogues method is inappropriate for this period. So, a new method is proposed: it corresponds to a climatic amplitude method modified to partially take into account some taxa abundances. The first step in this new method is to determine the present-day distribution of a few subtropical plants and some taxa still existing in the Mediterranean region with a good climatic signal. Then, the climatic parameters of the corresponding areas are defined, either by a climatic atlas or by personal knowledge. A test on a few pollen spectra, corresponding to different localities but of almost the same age (about 3.4 Ma) is realised. The first results of climatic estimation confirm an increasing latitudinal gradient for annual temperatures from North to South, which is estimated as today, even if the temperatures were higher (about 2 to 6 degrees C more). We may confirm the same for the precipitations which were more important to the North than to the South of the Mediterranean. These latitudinal gradients are quantified

Climate and biomes in the West Mediterranean area during the Pliocene

International audienceA new pollen-derived method of climatic quantification, based on the mutual climatic range of plant taxa, has been applied to 17 Pliocene pollen sequences in the West Mediterranean area. The latitudinal gradient observed in the pollen data was confirmed by the climatic reconstructions: there is a gradient from north to south both for temperatures and precipitation. At the beginning of the Pliocene (5.32-5 Ma), the climate in the North Mediterranean area was, on average, warmer and more humid than today (respectively 1-4 degrees C and 400-700 mm). In the South Mediterranean region, the climate was both warmer and drier than today (respectively equal to or 5 degrees C higher and drier or equal humidity). The pollen-based climate estimates were then used to reconstruct biomes for the region. The results show the occurrence of three biomes: the broad-leaved evergreen/warm mixed forest, the xerophytic woods/scrub biome and the warm grass/shrub biome. These biomes are still represented today in the Mediterranean region despite different thermic and water conditions. (C) 1999 Elsevier Science B.V. All rights reserved