Search results for "PLEISTOCENE"
showing 10 items of 298 documents
The late Pleistocene origin of the Italian and Maltese populations of Potamon fluviatile (Malacostraca: Decapoda): insights from an expanded sampling…
2017
Evidence available for most inland water and terrestrial organisms highlights the significant role played by southern Italy, Sicily and the Maltese islands as refuges during Pleistocene climatic fluctuations. However, to date, the hypothesis that these areas may have acted as Pleistocene refugia for the freshwater crab Potamon fluviatile has not been explicitly tested, and a recent origin of local P. fluviatile populations was proposed on the basis of a small set of analysed molecular data. We have thus expanded the currently available data set on the population genetic structure of P. fluviatile through dedicated samplings in Sicily (Italy, 18 specimens), the Maltese Islands (Malta, 15 spe…
Phylogeography ofSyringa josikaea(Oleaceae): Early Pleistocene divergence from East Asian relatives and survival in small populations in the Carpathi…
2015
Tertiary relict plant species of Europe have had a large distribution range before the Pleistocene but today are confined to small refugial areas. Syringa josikaea of the largely East Asian genus Syringa is a shrub of temperate forests in the Carpathians, restricted to altogether 25 small populations in two disjunct areas, the Apuseni Mountains (Romania) and the Ukrainian Carpathians. Miocene and Pleistocene fossil remains indicate the long-term presence of the species in Central Europe; hence S. josikaea has been considered a Tertiary relict. We aimed at clarifying the historical biogeography of S. josikaea by estimating the divergence time between S. josikaea and its Asian relatives, and …
The legacy of a vanished sea: a high level of diversification within a European freshwater amphipod species complex driven by 15 My of Paratethys reg…
2016
16 pages; International audience; The formation of continental Europe in the Neogene was due to the regression of the Tethys Ocean and of the Paratethys Sea. The dynamic geology of the area and repetitious transitions between marine and freshwater conditions presented opportunities for the colonization of newly emerging hydrological networks and diversification of aquatic biota. Implementing mitochondrial and nuclear markers in conjunction with a large-scale sampling strategy, we investigated the impact of this spatiotemporal framework on the evolutionary history of a freshwater crustacean morphospecies. The Gammarus balcanicus species complex is widely distributed in the area previously oc…
Pleistocene diversification in Morocco and recent demographic expansion in the Mediterranean pond turtle Mauremys leprosa
2016
Quaternary climatic oscillations and geographic barriers have strongly influenced the distribution and diversification of thermophilic species occurring in the Mediterranean Basin. The Western Mediterranean pond turtle, Mauremys leprosa, is widely distributed throughout the Iberian Peninsula, southern France and most of the Maghreb region, with two subspecies currently recognized. In this work, we used 566 samples, including 259 new individuals, across the species range, and sequenced two mitochondrial markers (cytochrome b gene and control region; 163 samples in a concatenated mtDNA dataset) and one nuclear intron (R35; 23 samples representing all identified sublineages) to study the evolu…
Following the Antarctic Circumpolar Current: patterns and processes in the biogeography of the limpet Nacella (Mollusca: Patellogastropoda) across th…
2017
14 pages; International audience; AimWe use an integrative biogeographical approach to further understand the evolution of an important Southern Ocean marine benthic element, the limpet genus Nacella (Mollusca: Patellogastropoda).LocationSouthern Ocean.MethodsWe used multi-locus time-calibrated phylogeny of Nacella at the scale of the whole Southern Ocean to elucidate the underlying processes involved in the origin and diversification of the genus.ResultsDivergence-time estimates suggest that soon after its origin during the mid-Miocene (c. 12.5 Ma), Nacella separated into two main lineages currently distributed in (1) South America and (2) Antarctica and the sub-Antarctic islands. We ident…
The evolution of dwarf shrubs in alpine environments: a case study ofAlchemillain Africa
2015
BACKGROUND AND AIMS Alpine and arctic environments worldwide, including high mountains, are dominated by short-stature woody plants (dwarf shrubs). This conspicuous life form asserts considerable influence on local environmental conditions above the treeline, creating its own microhabitat. This study reconstructs the evolution of dwarf shrubs in Alchemilla in the African tropical alpine environment, where they represent one of the largest clades and are among the most common and abundant plants. METHODS Different phylogenetic inference methods were used with plastid and nuclear DNA sequence markers, molecular dating (BEAST and RelTime), analyses of diversification rate shifts (MEDUSA and BA…
Neogene paleogeography provides context for understanding the origin and spatial distribution of cryptic diversity in a widespread Balkan freshwater …
2017
BackgroundThe Balkans are a major biodiversity and endemism hotspot, worldwide. Among the freshwater biota, amphipods are known for their high cryptic diversity. However, little is known about the temporal and paleogeographic aspects of their evolutionary history. We used paleogeography as a framework for understanding the onset of diversification inGammarus roeselii: (1) we hypothesised that, given the high number of isolated waterbodies in the Balkans, the species is characterised by high level of cryptic diversity, even on a local scale; (2) the long geological history of the region might promote pre-Pleistocene divergence between lineages; (3) given thatG. roeseliithrives both in lakes …
On the origin of the recent herpetofauna of Sicily: Comparative phylogeography using homologous mitochondrial and nuclear genes
2016
Abstract In contrast to oceanic, continental islands are expected to show less diversification and endemism and thus phylogeographic signatures of multiple colonization events from adjacent continents due to episodic connections by sea level changes. In order to test this situation for the herpetofauna of Sicily, we here focus on three amphibian and four reptile species-groups and investigate their phylogeographic relationships across the Sicily and Messina straits, where Plio-Pleistocene marine transgressions shortened the distances between (or connected) Sicily, North Africa and/or the Italian (Apennine) Peninsula. Using a multi-species, multi-marker phylogeographic approach (mitochondria…
Ancient DNA evidence for the loss of a highly divergent brown bear clade during historical times
2008
The genetic diversity of present-day brown bears (Ursus arctos) has been extensively studied over the years and appears to be geographically structured into five main clades. The question of the past diversity of the species has been recently addressed by ancient DNA studies that concluded to a relative genetic stability over the last 35,000 years. However, the post-last glacial maximum genetic diversity of the species still remains poorly documented, notably in the Old World. Here, we analyse Atlas brown bears, which became extinct during the Holocene period. A divergent brown bear mitochondrial DNA lineage not present in any of the previously studied modern or ancient bear samples was unc…
Revision of the Afrotropical genus Leiodontocercus (Orthoptera, Tettigoniidae, Phaneropterinae) with a description of four new species
2020
Specimens belonging to the genus Leiodontocercus are rare or even absent in natural history museum collections; this is likely due to at least two reasons, notably, their relatively small size, and, the sheer difficulty in finding them in dense Afrotropical forests. Until recently, three species from less than fifteen specimens were known from this genus, whose identification relied on a singular diagnostic character, that is, the shape of the male cerci. The present contribution is based on the examination of thirty specimens collected from various countries, ranging from central to west Africa; apart from the male cerci, a second diagnostic character – the stridulatory file – is used to d…