Data sets of Central European temporal distributions of thermophilic ectothermic vertebrates (Channidae, Varanidae, Chamaeleonidae, Cordylidae, Tomistomidae, Alligatoridae, giant turtles) and of North Alpine Foreland Basin (NAFB) distributions of ectothermic vertebrates adapted to dryer habitats (Albanerpeton inexpectatum, Salamandra sansaniensis, Bufo cf. viridis, Chamaeleo caroliquarti, Gekkonidae, Varanus hofmanni, Bransateryx sp.) are analysed. Two main migration events of thermophilic ectotherms at 20 Ma and 18 Ma in the Lower Miocene are discerned. They indicate the beginning of the Miocene Climatic Optimum in Central Europe (42^45 ‡N palaeolatitude) with a lower limit of the mean annual temperature (MAT) of 17.4 ‡C derived from the minimal MAT of their extant relatives. Furthermore, additional palaeobotanical data and records of bauxite point to a MAT of 22 ‡C. This warm and humid optimum peaked at 18^16.5 Ma (Ottnangian, Karpatian), and is confirmed by the coexistence of all investigated thermophilic taxa. The following period (Early Badenian) is characterised by probably unchanged temperatures but a seasonality in precipitation with dry periods up to six months. Two major seasonal phases between 16.3 and V15.7 Ma (earliest Early Badenian) and between 14.7 and V14.5 Ma (Early/Middle Badenian transition) are indicated by an immigration of dry adapted taxa from the surrounding karst plateau to the NAFB. It is presumed that the tectonical reorganisation of the Central Paratethys realm had considerable influence on this regional humidity pattern. The warm period ended abruptly between 14.0 and 13.5 Ma (Middle/Late Badenian transition) with major regional extinction events of most of the thermophilic groups in Central Europe and a drop of the MAT of probably more than 7 ‡C to temperatures around 14.8^15.7 ‡C. This drop can be attributed predominantly to a decrease of more than 11 ‡C of the minimum cold months temperature. This temperature decrease marked the beginning of a climatic zonation of the European continent and is also evidenced by a progressively southward disappearance of the crocodile Diplocynodon from 38^45 ‡N palaeolatitude to 30^37 ‡N during the Middle and earliest Late Miocene. The results correlate well with palaeobotanical data from the mid-latitudes of Europe and North America, and the deep-sea temperature curve generated from oxygen isotope ratios. ß
BackgroundLeuciscinae is a subfamily belonging to the Cyprinidae fish family that is widely distributed in Circum-Mediterranean region. Many efforts have been carried out to deciphering the evolutionary history of this group. Thus, different biogeographical scenarios have tried to explain the colonization of Europe and Mediterranean area by cyprinids, such as the "north dispersal" or the "Lago Mare dispersal" models. Most recently, Pleistocene glaciations influenced the distribution of leuciscins, especially in North and Central Europe. Weighing up these biogeographical scenarios, this paper constitutes not only the first attempt at deciphering the mitochondrial and nuclear relationships of Mediterranean leuciscins but also a test of biogeographical hypotheses that could have determined the current distribution of Circum-Mediterranean leuciscins.ResultsA total of 4439 characters (mitochondrial + nuclear) from 321 individuals of 176 leuciscine species rendered a well-supported phylogeny, showing fourteen main lineages. Analyses of independent mitochondrial and nuclear markers supported the same main lineages, but basal relationships were not concordant. Moreover, some incongruence was found among independent mitochondrial and nuclear phylogenies. The monophyly of some poorly known genera such as Pseudophoxinus and Petroleuciscus was rejected. Representatives of both genera belong to different evolutionary lineages. Timing of cladogenetic events among the main leuciscine lineages was gained using mitochondrial and all genes data set.ConclusionsAdaptations to a predatory lifestyle or miniaturization have superimposed the morphology of some species. These species have been separated into different genera, which are not supported by a phylogenetic framework. Such is the case of the genera Pseudophoxinus and Petroleuciscus, which real taxonomy is not well known. The diversification of leuciscine lineages has been determined by intense vicariant events following the paleoclimatological and hydrogeological history of Mediterranean region. We propose different colonization models of Mediterranean region during the early Oligocene. Later vicariance events promoted Leuciscinae diversification during Oligocene and Miocene periods. Our data corroborate the presence of leuciscins in North Africa before the Messinian salinity crisis. Indeed, Messinian period appears as a stage of gradually Leuciscinae diversification. The rise of humidity at the beginning of the Pliocene promoted the colonization and posterior isolation of newly established freshwater populations. Finally, Pleistocene glaciations determined the current European distribution of some leuciscine species.
It is known from present-day climates that both temporal and spatial variations in precipitation can be more pronounced than those in temperature and thus influence ecosystems and human society in more substantial way. However, very little is known about such variations in the past. Here we present an analysis of 206 palaeoprecipitation data from two twelve million year long proxy records of precipitation for Southwest (Calatayud-Teruel basin) and Central Europe (Western and Central Paratethys), spanning the late Early and Middle to Late Miocene (17.8-5.3 Ma) at a temporal resolution of about 80 kyr and 200 kyr, respectively. The estimates of precipitation are based on the ecophysiological structure of herpetological assemblages. The results show that precipitation variations in both regions have large amplitudes during the Miocene with comparable temporal trends at longer time scales. With locally 300 mm up to more than 1000 mm more rainfall per year than present, the early Langhian and the Tortonian were relatively wet periods, whereas the late Langhian and late Serravallian were relatively dry, with up to 300 to 500 mm less precipitation than present. The most humid time intervals were the early and middle Tortonian washhouse climate periods. Overall, our data suggest that the latitudinal precipitation gradient in Europe from the Middle to Late Miocene were highly variable, with a general tendency towards a reduced gradient relative to present day values. The gradient decreases during cooling periods and increases during warming periods, similar to results from simulations of future climate change. Interestingly, the precipitation gradient was reversed during the second washhouse climate period and the Early Messinian, which may have causes a negative hydrologic balance in the Eastern Paratethys during the latter time. Yet, our reconstructed gradient curve shows no direct correlation with the global temperature signal from oxygen isotopes, which implies a non-linear regional response. Our results further suggest that major fluctuations in the precipitation gradient can be responsible for shifts in ecosystem distribution, and particularly, for faunal turnover in South Western Europe.
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