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Aim: Arctic plants survived the Pleistocene glaciations in unglaciated refugia. The number, ages, and locations of these refugia are often unclear. We use high‐resolution genomic data from present‐day and Little‐Ice‐Age populations of Arctic Bell‐Heather to re‐evaluate the biogeography of this species and determine whether it had multiple independent refugia or a single refugium in Beringia. Location: Circumpolar Arctic and Coastal British Columbia (BC) alpine. Taxon: Cassiope tetragona L., subspecies saximontana and tetragona, outgroup C. mertensiana (Ericaceae). Methods: We built genotyping‐by‐sequencing (GBS) libraries using Cassiope tetragona tissue from 36 Arctic locations, including two ~250‐ to 500‐year‐old populations collected under glacial ice on Ellesmere Island, Canada. We assembled a de novo GBS reference to call variants. Population structure, genetic diversity and demography were inferred from PCA, ADMIXTURE, fastsimcoal2, SplitsTree, and several population genomics statistics. Results: Population structure analyses identified 4–5 clusters that align with geographic locations. Nucleotide diversity was highest in Beringia and decreased eastwards across Canada. Demographic coalescent analyses dated the following splits with Alaska: BC subspecies saximontana (5 mya), Russia (~1.4 mya), Europe (>200–600 kya), and Greenland (~60 kya). Northern Canada populations appear to have formed during the current interglacial (7–9 kya). Admixture analyses show genetic variants from Alaska appear more frequently in present‐day than historic plants on Ellesmere Island. Conclusions: Population and demographic analyses support BC, Alaska, Russia, Europe and Greenland as all having had independent Pleistocene refugia. Northern Canadian populations appear to be founded during the current interglacial with genetic contributions from Alaska, Europe and Greenland. We found evidence, on Ellesmere Island, for continued recent gene flow in the last 250–500 years. These results suggest that a re‐analysis of other Arctic species with shallow population structure using higher resolution genomic markers and demographic analyses may help reveal deeper structure and other circumpolar glacial refugia. [ABSTRACT FROM AUTHOR]

The evolutionary dynamics of the ecoregions of southern South America and the species that inhabit them have been poorly studied, and few biogeographic hypotheses have been proposed and tested. Quaternary climatic oscillations are among the most important processes that have led to the current distribution of genetic variation in different regions of the world. In this work, we studied the evolutionary history and distribution of the Córdoba vesper mouse (Calomys venustus), a characteristic rodent of the region of which little is known about its natural history. Since the population dynamics of this species are influenced by climatic factors, this rodent is a suitable model to study the effects of Quaternary climatic oscillations in central Argentina. The mitochondrial cytochrome b gene was sequenced to analyze the phylogeography of C. venustus, and ecological niche modeling tools were used to map its potential distributions. The results of these approaches were combined to provide additional spatially explicit information about this species' past. Our results suggest that the Espinal was the area of origin of this species, which expanded demographically and spatially during the last glacial period. A close relationship was found between the Espinal and the Mountain Chaco. These results are consistent with previous studies and emphasize the role of the Espinal in the biogeographic history of southern South America as an area of origin of several species. [ABSTRACT FROM AUTHOR]

Montane biodiversity is particularly vulnerable to rapid oscillations in environmental conditions. Recent modelling showed that only three of the 19 butterfly species of Erebia (Nymphalidae, Satyrinae) currently present in Iberia would persist in a worst‐case scenario for 2070. One of them is Erebia palarica, endemic to Northwest Spain. We combined genetics, morphometrics and ecological niche modelling to reconstruct its evolutionary history.First, sequences of the cytochrome oxidase I (COI) mitochondrial gene obtained from 305 specimens revealed a double star‐like network that suggests a demographic expansion from two ancestral populations. This finding is congruent with the larger and disjunct putative distribution revealed by climatic modelling during the Last Glacial Maximum.Second, genotyping of 262 samples with seven microsatellite markers produced a large cluster at the centre‐East of the Cantabrian range, mostly affected by isolation by distance, and revealed different levels of structure in the western localities.Lastly, we reviewed the intraspecific taxonomy of the species. The westernmost site (Queixa) stands as a clearly separated unit according to genetic and morphometric analyses, which further supports its vague former description as subspecies E. p. castroviejoi.Altogether, the case of E. palarica exemplifies the complexity that narrow endemics can show and highlights that understanding the evolutionary history of species is crucial for designing adequate conservation strategies. [ABSTRACT FROM AUTHOR]

Kamchatka is a global geological brand. It is part of the complex active subduction zone between the Pacific and Eurasian tectonic plates, generating intense volcanism. Understanding the volcanic activity is important both for mitigation of natural hazards and using geothermal energy. However, the incredible geodiversity can also be used for geotourism which could be of great social importance through geopark establishment. The geological heritage of Kamchatka is dominated by an extraordinary variety of volcanic and glacial landscapes, which are inextricably linked because the interaction between them is distinct and continuous. Its geotourism potential is examined in the light of the “thematic geodiversity approach,” which is based on one clearly defined main theme and many minor themes adding value to the geological heritage. Kamchatka is a more special type of volcano destination representing extremely intensive volcanic activity. The main theme of Kamchatka is volcanic activity, including at least twenty-nine active volcanoes, geyser valleys, and numerous thermal springs, which contain many geosites of global significance. A tentative inventory of 40 geosites is proposed including active, dormant, and extinct volcanoes as a basis for development of volcano tourism. The secondary topic, which is no less important than volcanism, is based on the glacial activity that has scarred the relief of Kamchatka with picturesque cirques, scenic fjords, and trough valleys flowing into the Pacific Ocean. These themes are complemented by many geosites of scientific, aesthetic, historical, and cultural value, including geological cycles and events, inspirational wild landscapes, and ancient artifacts that testify to the long human history of this remarkable peninsula. An important task of the future geopark management is the safety of visitors given the harsh field conditions and the remoteness of most of the geosites. The distinctive way of life and culture of the local minorities such as Koryaks and Evens is part of the intangible cultural heritage of the world. The outstanding geoheritage is an excellent basis for raising the protection of the natural and cultural heritage of Kamchatka to a higher level through the development of geoparks that will contribute to its global promotion. [ABSTRACT FROM AUTHOR]

A critical verification of the previous stratigraphic Quaternary subdivisions has updated the setting of the stratigraphic units in Poland. Inconsequently applied classification and terminology in the Polish Quaternary stratigraphy has been accompanied by arbitrary correlation with marine isotope stages. This has resulted in the creation of several stratigraphic units, occasionally with ambiguous stratigraphic setting and chronology, and usually devoid of the type sections. A record of most of the Early and Middle Pleistocene is full of sedimentary hiatuses. The detailed stratigraphic setting of 5 glaciations (Nidanian, Sanian 1, Sanian 2, Odranian and Vistulian) and 4 interglacials (Podlasian, Ferdynandovian, Mazovian and Eemian) has been established in the Pleistocene of Poland. The palaeomagnetic Brunhes/Matuyama boundary was determined within the Podlasian Interglacial and therefore, the oldest glaciation (Nidanian) has no equivalent anywhere in Europe. The stratigraphic units distinguished are correlated with those in Western Europe and with the marine isotope stages. The Quaternary stratigraphy in Poland is faced with the necessity of how to define regional stratotypes of the main stratigraphic units and boundaries. A crucial issue is to change the approach from a qualitative description of the stratigraphic units to one based also on selected quantitative criteria. [ABSTRACT FROM AUTHOR]

The use of geological–geomorphological and geochronological (14C, OSL) methods allowed establishing that the bordering mountains of the Chuya basin (Russian Altai) were affected by glaciation as early as the Middle Pleistocene, about 160–180 ka (MIS 6). However, the ice-dammed lake with the highest (up to 2100 m a.s.l.) strandlines in the Chuya and Kurai basins existed later than 90–80 ka, i.e., in the Late Pleistocene. This chronological benchmark limits the influence of the catastrophic outburst floods of the largest lakes on the accumulation of the Inya formation in the Chuya and Katun river valleys. It is confirmed that a large ice-dammed lake existed and had a water level of at least 1730 m a.s.l. in MIS 2 in the Kurai basin. The lake drained no later than 16 ka. Synchronously (about 17–16 ka) the accumulation of diluvial–lacustrine cyclites began in the Inya mouth. It was found that the accumulation of the Saldzhar formation in the Katun River valley between the mouths of the Chuya and Sema rivers was long-lasting during the entire MIS 2 not only as a result of flood events, but also due to gradual hydrological processes. It is necessary to revise the concept adopted by SibRISC in 2018. This concept assumes (i) the absence of ice-dammed lakes in intermont basins of Russian Altai in MIS 2 and (ii) the accumulation of the Inya and Saldzhar catafluvial formations, as well as the high and medium terraces they deposited in the valleys of the Chuya and Katun rivers before 90 ka. [ABSTRACT FROM AUTHOR]

On the basis of data collected since 1961, the authors of the current article conducted an analysis of the distribution of Uropodina (Acari: Mesostigmata) species in Poland. The areas of occurrence of the species were compared with the range boundaries of the successive Pleistocene glaciations in Poland. The second aim of the study was to establish the importance of the former nunataks (paleonunataks) for the preservation of biodiversity of this group of mites in Poland. The study has revealed that there are six types of distribution of Uropodina species in the area of Poland: (i) species distributed consistently in the whole area of the country, (ii) species having their northern range of occurrence in Poland, (iii) species having their north-western range of occurrence, (iv) species having their north-eastern range of occurrence, (v) species of boreal-mountainous distribution with evident disjunction in central Poland, and (vi) Carpathian species migrating northwards along the Vistula River. The analyses of the species composition of Uropodina communities on nunataks shows that the concave nunatak in Jura Krakowsko-Czestochowska, described in the literature as the "Jurassic Inland Oasis", turned out to be the location with the highest Uropodina diversity, whereas on the nunatak of the Ślęża Massif, which was covered by two glaciations, the Uropodina diversity was the lowest. [ABSTRACT FROM AUTHOR]

Geomorphological mapping in mountain regions is key for a better understanding of past and present environmental dynamics. Here, we present a 1:25000 scale geomorphological map covering 553 km2 of the Aran Valley, Upper Garonne Basin (Central Pyrenees). The map identifies 44 different geomorphological units classified under glacial, periglacial, nival, karst, slope, alluvial, and fluvial categories. The area includes geomorphic evidence of past Quaternary glaciations reconstructed based on the distribution of moraines from the valley floor to the highest cirques. Following deglaciation of the valley, the landscape was mainly reshaped by periglacial, slope, alluvial and fluvial processes. In addition to paleoenvironmental reconstruction, the map can also be used to promote geoheritage and geoconservation, as well as for planning. As such, it is of relevance for areas exposed to natural hazards, since present-day slope failures and debris flows frequently impact the villages and infrastructures across the valley floor.

Enduring questions remain regarding the transition from relatively warm and stable pre‐ and early‐Pleistocene climate to that of the high amplitude glacial‐interglacial cycles later in the Quaternary. The main shift in glacial intensity and periodicity around 1 Ma is known as the Mid‐Pleistocene Transition (MPT). Here we analyze detrital strontium (Sr) and neodymium (Nd) isotopes in a western Arctic sediment core P23 previously investigated using several litho/biostratigraphic proxies. Based on an improved age framework combining lithostratigraphic cyclicity and Sr isotope stratigraphy, the P23 record extends to ∼3.3 Ma, thus providing a rare insight into the Quaternary Arctic climate change. The distinct pre‐MPT P23 record is dominated by Pacific‐sourced sediment inputs, with little to no intra‐Arctic glacial inputs, except for a sandy interval around ∼2.5 Ma. A consistent decrease of Nd isotopic values toward North American continental signatures started in both the Arctic and Bering Sea at ∼1.5 Ma and led to a major threshold shift in P23 proxies at ∼0.9 Ma. We argue that this threshold was associated with the first prolonged closure of the Bering Strait for an entire obliquity cycle. This shift marked the expansion of the North American ice sheets to the Arctic margin, with dramatic impacts on depositional and hydrographic environments in the Arctic Ocean. These impacts intensified in the subsequent glacial intervals indicating further ice‐sheet growth, probably fed back by continuing prolonged Bering Strait closures. Plain Language Summary: A significant change in Earth's climate system, the Mid‐Pleistocene Transition (MPT), happened around 1 million years ago and caused ice‐ages to become longer and colder. To improve our understanding of this transition we analyzed the isotopes of strontium (Sr) and neodymium (Nd) in a marine sediment core from the Western Arctic Ocean. Based on this and previous work done on the same core, we show that material mostly came from the south through the Bering Strait in the first half of our record. The isotopic ratios of Sr and Nd in our core indicate an increasing contribution of material from the North American continent starting around 1.5 million years ago, building up to the MPT when larger sediment grains abruptly appear; an indication of massive ice sheet growth and a resulting discharge of icebergs into the Arctic Ocean. We argue that this major change happened coincident with the first time the Bering Strait was closed—due to a sea level drop caused by the growth of ice on land—through an interglacial period. After this event, subsequent massive ice sheets and prolonged Bering Strait closures worked together to create longer and colder glacial periods than were seen before the MPT. Key Points: We measured strontium and neodymium isotope ratios on the lithogenic fractions of a sediment core from the Western ArcticThe sediment record covers the past 3.3 million years of change in the Arctic, a critical and understudied time period in this regionProlonged closures of the Bering Strait are important to the intensification of glacial cycles at the Mid‐Pleistocene Transition [ABSTRACT FROM AUTHOR]

The southern extreme location and the natural landscapes, highly modelled by glaciers during the Quaternary period, give Tierra del Fuego a unique opportunity to attract visitors worldwide. Its glacial landforms are geodiversity resources that are witness to global climate changes as natural processes. Therefore, this study aims to highlight different glacial landforms considering their geodidactic potential for educational information in terms of geographical study. Sixteen georesources connected by routes are analysed, using bibliographic research, fieldwork and a datasheet designed ad-hoc. Four of them were formed during middle Pleistocene glaciations and the other twelve during the Last Glacial Maximum (LGM), out of which two also represent the Holocene, which happens to be the youngest glaciation.

Abstract Background For the genus Thylamys, the rivers have been reported as barriers to dispersal, limiting current and historical distribution of its lineages. We hypothesized that the Maipo river has affected the genetic structure of northern and southern lineages of Thylamys elegans, recovering a phylogenetic relationships with reciprocally monophyletic sister groups on opposite river banks. We evaluated the role of other rivers in the Mediterranean zone of Chile as historical and recent modulators of the biogeographic processes of this species. Methods We applied a phylogeographic approach, using the cytochrome-b mitochondrial gene for 93 individuals of T. elegans, from 37 localities in a latitudinal gradient between 21°25’ and 35˚56’S, encompassing a geographic area between the Atacama Desert and most of the Mediterranean Chilean zone. Results The phylogenetics results recovered six lineages within T. elegans: Thylamys elegans elegans, Thylamys elegans coquimbensis, the Loa lineage and three other lineages not described previously (Aconcagua, South 1 and South 2). We suggest that following rivers play a role like primary barrier: the Maipo river in the genetic differentiation of northern and southern ancestral lineages, and the Mataquito river and its tributary Teno river for the South 1 and South 2 lineages. On the other hand, the Quilimarí river preserve the genetic divergence in T. e. coquimbensis and Aconcagua lineage and the Aconcagua river in Aconcagua lineage and T. e. elegans acting like secondary barriers. Conclusions We concluded that the genetic diversity and biogeographic history of T. elegans was shaped by mountain glaciers, changes in river water levels during the Pleistocene glaciations and hyperaridity, promoting the differentiation and persistance of the T. elegans lineages.

The cold climate events of the Upper Cenozoic greatly modified the landscape of Patagonia, where a large number of relicts and active landforms of glacial, periglacial and paraglacial origin is preserved. To assess the regional paleoclimatic record when numerical ages are unavailable, the spatial distribution of local depositional landform sequences was analyzed in six mountain ranges located on the eastern margin of the North Patagonian Andes. The analysis of satellite images and digital elevation model, fieldwork research and its integration into a Geographical Information System were used to develop a detailed inventory of mountain landforms. A total of 67 glacial valleys, 97 glacial cirques, 94 moraines, 75 rock glaciers, 103 protalus ramparts, and more than 145 km2 and 100 km2 of surface affected by solifluction and mass wasting processes respectively were mapped. From the analysis of the spatial and altitudinal distribution of landforms, we defined temporal and spatial sequences of morpho-climate importance. We recognized four major morpho-climate events associated with local paleoclimate conditions and one stage of a recent paraglacial adjustment. The oldest cold climate event recognized might be correlated with the Last Glacial Maximum. The results show the rise in the average air temperature and an aridity trend for the study area since the Late Pleistocene. During this lapse, glacial environments evolved to periglacial environments, although was recognized their coexistence in some areas in the same mountain range. • Eastern North Patagonian Andes preserve numerous glacial and periglacial landforms. • Glacial and periglacial landforms reveal four major cold climate events. • Landform sequences show a transition between glacial and periglacial environments. • The oldest event may be correlated with the Last Glacial Maximum (LGM). • The youngest event might be linked to the Little Ice Age (LIA). [ABSTRACT FROM AUTHOR]

Calceolaria (Calceolariaceae) is an emblematic and diverse genus in the Americas. Despite being one of the most easily recognized genera in the region and a system with great potential to improve our understanding of different drivers of species diversification in the Andes, its intrageneric evolutionary relationships are still poorly understood. Responding to the need for additional molecular markers to resolve the phylogenetic relationships of the group, we perform plastome analyses and resolve the backbone of the genus. Specifically, using low-coverage genomes for 14 species, we assembled plastomes, estimated and dated phylogenetic hypotheses and evaluated evolutionary trends in the group. Our approach allowed us to resolve the backbone of the genus, identify two main clades and estimate a timing of diversification contemporaneous to major climatic and orogenic events. Our biogeographic reconstructions suggest an independent colonization of the whole range of the genus by both clades. Finally, our evaluations of floral morphology reveal future avenues for investigating the relationship between the pollination biology and diversification of the group. [ABSTRACT FROM AUTHOR]

The Chuy Formation is characterized by up to 135 m of an alternation of green pelites and fine to coarse sandstones with sparse invertebrate fossils. The marine deposits are interbedded with continental, loessic deposits of the Libertad Formation and overlain by the Dolores Formation, made up of mudstones with calcareous concretions. The results of the radiocarbon dating showed calibrated ages of 13.9±0.2, 41.5±1.9 and 50±3 ka BP on bioclasts of marine fossils at an elevation (above sea level, asl) of -2.8, -6.13 and -8 m respectively. Such ages and elevations are in disagreement with the sea-level evolution inferred for the Late Pleistocene. Two possible explanations are: (a) the ages represent minimum ages and deposition took place during the last interglacial at 115-130 ka (Marine Isotope Stage MIS 5e), or (b) they represent depositional ages but the area experimented large isostatic readjustments during and after the last glaciation. Several lines of evidence suggest a Late Pleistocene age for the upper Chuy Formation, including the d18O curve obtained from invertebrate shells, which shows large secular variations consistent with MIS 1 to 7. The proposed scenario envisages significant subsidence between 50-20 ka due to the far-field effects of glacial load in the Andes/Patagonia. At 20 ka the eustatic regression outpaced subsidence, leading to continentalization of the Laguna de Rocha area. Marine conditions returned at 15 ka and into the Holocene, except for continental deposits (Dolores Formation) at ca. 11-10 ka (Younger Dryas). An uplift of 115 m took place between 15 and 9 ka in the area, which is interpreted as post-glacial rebound. In the Holocene, moderate subsidence was further recorded. A regional trend is observed, with uplift of marine deposits increasing towards the W-SW, which is consistent with an explanation as post-glacial isostatic rebound.

Geomorphological mapping in mountain regions is key for a better understanding of past and present environmental dynamics. Here, we present a 1:25000 scale geomorphological map covering 553 km² of the Aran Valley, Upper Garonne Basin (Central Pyrenees). The map identifies 44 different geomorphological units classified under glacial, periglacial, nival, karst, slope, alluvial, and fluvial categories. The area includes geomorphic evidence of past Quaternary glaciations reconstructed based on the distribution of moraines from the valley floor to the highest cirques. Following deglaciation of the valley, the landscape was mainly reshaped by periglacial, slope, alluvial and fluvial processes. In addition to paleoenvironmental reconstruction, the map can also be used to promote geoheritage and geoconservation, as well as for planning. As such, it is of relevance for areas exposed to natural hazards, since present-day slope failures and debris flows frequently impact the villages and infrastructures across the valley floor. [ABSTRACT FROM AUTHOR]

The southern extreme location and the natural landscapes, highly modelled by glaciers during the Quaternary period, give Tierra del Fuego a unique opportunity to attract visitors worldwide. Its glacial landforms are geodiversity resources that are witness to global climate changes as natural processes. Therefore, this study aims to highlight different glacial landforms considering their geodidactic potential for educational information in terms of geographical study. Sixteen georesources connected by routes are analysed, using bibliographic research, fieldwork and a datasheet designed ad-hoc. Four of them were formed during middle Pleistocene glaciations and the other twelve during the Last Glacial Maximum (LGM), out of which two also represent the Holocene, which happens to be the youngest glaciation. [ABSTRACT FROM AUTHOR]

The faunal, molecular, and palaeogeographic data that make it possible to discuss where and when aquatic animals could have crossed the watershed divide between the basins of the Caspian Sea and the Arctic Ocean are discussed. The freshwater fauna of Europe and northern Asia were largely similar in the Pliocene, while Pliocene fauna in Siberia went almost totally extinct during the Pleistocene glaciations. In interglacial periods, cold-water freshwater organisms colonized the Volga River basin, most likely during dispersal events from the basins of the Pechora and Ob' rivers. Marine animals might have found their way into the Caspian Sea with saline waters arriving from the Arctic Ocean in the late Pliocene and early Pleistocene epochs. There was probably no possibility to cross the watershed divide during the last glacial period. After this period had ended, freshwater organisms, including mostly warm-water groups, entered the basins of the Onega, Northern Dvina, and Ob' rivers as the watershed divide shifted to another location. Similar expansions currently take place due to human-mediated introduction and dispersal events through the channels connecting the Volga and Northern Dvina river basins. [ABSTRACT FROM AUTHOR]

Background: For the genus Thylamys, the rivers have been reported as barriers to dispersal, limiting current and historical distribution of its lineages. We hypothesized that the Maipo river has affected the genetic structure of northern and southern lineages of Thylamys elegans, recovering a phylogenetic relationships with reciprocally monophyletic sister groups on opposite river banks. We evaluated the role of other rivers in the Mediterranean zone of Chile as historical and recent modulators of the biogeographic processes of this species. Methods: We applied a phylogeographic approach, using the cytochrome-b mitochondrial gene for 93 individuals of T. elegans, from 37 localities in a latitudinal gradient between 21°25' and 35˚56'S, encompassing a geographic area between the Atacama Desert and most of the Mediterranean Chilean zone. Results: The phylogenetics results recovered six lineages within T. elegans: Thylamys elegans elegans, Thylamys elegans coquimbensis, the Loa lineage and three other lineages not described previously (Aconcagua, South 1 and South 2). We suggest that following rivers play a role like primary barrier: the Maipo river in the genetic differentiation of northern and southern ancestral lineages, and the Mataquito river and its tributary Teno river for the South 1 and South 2 lineages. On the other hand, the Quilimarí river preserve the genetic divergence in T. e. coquimbensis and Aconcagua lineage and the Aconcagua river in Aconcagua lineage and T. e. elegans acting like secondary barriers. Conclusions: We concluded that the genetic diversity and biogeographic history of T. elegans was shaped by mountain glaciers, changes in river water levels during the Pleistocene glaciations and hyperaridity, promoting the differentiation and persistance of the T. elegans lineages. [ABSTRACT FROM AUTHOR]

The Pamir Mountains are one of the highest mountain systems in the world; they act as sources of fresh water for the main rivers of Central Asia: the Amudaria and Syrdaria. Throughout the Quaternary, the Pamirs played a major role in controlling atmospheric circulation and land-surface processes, and provided great volumes of terrigenous sediments for transport by large rivers to the depressions in the Aral and Caspian regions. These ultimately provided broad aeolian cover in the sandy deserts, and finer dust for the widely distributed loess-palaeosol sequences. The glaciation history of this highly dynamic region provides an important basis for understanding climate change, sediment source and landscape evolution in Central Asia during the Quaternary. The question of the number, distribution, extent and timing of Pleistocene glaciations in the Pamir is debated. One of the main obstacles to research, together with difficulties of access and severity of current climate, is the varying degree of preservation of traces of previous glaciations in the western and eastern Pamir. As a result of a geological survey, we for the first time identified a thick lacustrine deposit at high altitudes in a tributary of the Panj – the valley of the Sary-Shitharv River – this records the damming of the Panj River valley by a large glacier. Luminescence measurements were undertaken to obtain the age of the Sary-Shitharv glacially-dammed lake. As often in mountain catchments the quartz OSL signal was unsuitable for dose estimation, and so the chronology of the Sary-Shitharv section is based entirely on post-IR IRSL signals from K-rich feldspar. We used pIRIR 50,290 and pIRIR 200,290 protocols and obtained indistinguishable ages from both protocols. Given the high sedimentation rates deduced from the structure of lacustrine deposits, the entire sequence must have been accumulated rather quickly, over a period of no more than a few thousand years. The average age over the whole series of dates is 165 ± 11 ka. This places the existence of the glacially-dammed lake at Sary-Shitharv in late MIS 6, a result that fits well with the general course of the glacial history of the Pamirs. [ABSTRACT FROM AUTHOR]

Abstract Background The flat periwinkles, Littorina fabalis and L. obtusata, are two sister species widely distributed throughout the Northern Atlantic shores with high potential to inform us about the process of ecological speciation in the intertidal. However, whether gene flow has occurred during their divergence is still a matter of debate. A comprehensive assessment of the genetic diversity of these species is also lacking and their main glacial refugia and dispersal barriers remain largely unknown. In order to fill these gaps, we sequenced two mitochondrial genes and two nuclear fragments to perform a phylogeographic analysis of flat periwinkles across their distribution range. Results We identified two main clades largely composed by species-specific haplotypes corresponding to L. obtusata and L. fabalis, with moderate to strong support, respectively. Importantly, a model of divergence with gene flow between the two species (from L. obtusata to L. fabalis) was better supported, both in Iberia and in northern-central Europe. Three mitochondrial clades were detected within L. fabalis and two within L. obtusata, with strong divergence between Iberia and the remaining populations. The largest component of the genetic variance within each species was explained by differences between geographic regions associated with these clades. Our data suggests that overall intraspecific genetic diversity is similar between the two flat periwinkle species and that populations from Iberia tend to be less diverse than populations from northern-central Europe. Conclusions The phylogeographic analysis of this sister-species pair supports divergence with gene flow. This system thus provides us with the opportunity to study the contribution of gene flow and natural selection during diversification. The distribution of the different clades suggests the existence of glacial refugia in Iberia and northern-central Europe for both species, with a main phylogeographic break between these regions. Although the genetic diversity results are not fully conclusive, the lower diversity observed in Iberia could reflect marginal conditions at the southern limit of their distribution range during the current interglacial period.

Abstract We provide preliminary insights into the global phylogeographic and evolutionary patterns across species of the hydrozoan superfamily Plumularioidea (Cnidaria: Hydrozoa). We analyzed 1,114 16S sequences of 198 putative species of Plumularioidea collected worldwide. We investigated genetic connections and divergence in relation to present‐day and ancient biogeographic barriers, climate changes and oceanic circulation. Geographical distributions of most species are generally more constrained than previously assumed. Some species able to raft are dispersed widely. Human‐mediated dispersal explains some wide geographical ranges. Trans‐Atlantic genetic connections are presently unlikely for most of the tropical‐temperate species, but were probably more frequent until the Miocene–Pliocene transition, before restriction of the Tethys Sea and the Central American Seaway. Trans‐Atlantic colonizations were predominantly directed westwards through (sub)tropical waters. The Azores were colonized multiple times and through different routes, mainly from the east Atlantic, at least since the Pliocene. Extant geminate clades separated by the Isthmus of Panama have predominantly Atlantic origin. Various ancient colonizations mainly directed from the Indian Ocean to the Atlantic occurred through the Tethys Sea and around South Africa in periods of lower intensity of the Benguela upwelling. Thermal tolerance, population sizes, dispersal strategies, oceanic currents, substrate preference, and land barriers are important factors for dispersal and speciation of marine hydroids.

The eastern part of the North Anatolian Mountains is the place where the Pleistocene glaciations is most effective.In these mountains, which have many summits over 3500 meters, especially the high parts above 2500 meters constitute a significant glacial area. Important peaks of the Eastern Black Sea Mountains; Glaciers and glacier shapes on the northern slopes of Kaçkar, Verçenik, Tatos (Dilek), Göller(Hunut) and Bulut-Altiparmak have been subject to various investigations because of these features. In the Eastern Black Sea Mountains, there are also some glacial traces, glacial shapes, and even current cirque glaciers in the southern-facing parts of these summits. The southern part of the Tatos Mountains, which forms one of the highest peaks of the Eastern Black Sea Mountains, is also where glaciation is effective.The glacier valleys reflecting the traces of the Pleistocene glaciations, the various glacial shapes and glacier lakes together with the northward-facing Çatakkaya debris covered glacier, covered entirely with a rubble, detected at the steep slope of a glacial cirque is a significant finding that reveals the impact and significance of glaciation in this area.

For the first time, a series of 10 isotopic K–Ar ages was obtained for the lava centers of the Sedankinsky Dol, located in the northern part of the Sredinny Range of Kamchatka. We show that volcanism in this area started at least in the Middle Pleistocene. For the pre-Holocene time, four stages of volcanism activation were distinguished (300–270, 180–160, 100–80, and between 50 and 12 ka BP), separated by significant periods of dormancy. The beginning of volcanic activity and the first supply of basic magmas to the Dol were apparently caused by regional reasons for the increase of endogenous activity. The obtained geochronological data cast doubt on either the age or the genesis of the moraine complexes of the first and second phases of the Late Pleistocene glaciation which were previously identified for this region. Analysis of lithological-petrographic and isotope-geochronological data indicates that about 100–80 ka a large avalanche descended from the near-watershed part of the ridge. The deposits of this avalanche were previously identified as "phase I moraine". This event could have been triggered by a high-magnitude earthquake, preceding and/or accompanying a new stage of volcanism activation, when the earliest eruptions of olivine basalts were recorded. [ABSTRACT FROM AUTHOR]

Aim: Alpine habitats support unique biodiversity confined to high‐elevation areas in the current interglacial. Plant diversity in these habitats may respond to area, environment, connectivity and isolation, yet these factors have been rarely evaluated in concert. Here we investigate major determinants of regional species pools in alpine grasslands, and the responses of their constituent species groups. Location: European mountains below 50° N. Time period: Between 1928 and 2019. Major taxa studied: Vascular plants. Methods: We compiled species pools from alpine grasslands in 23 regions, including 794 alpine species and 2,094 non‐alpines. We used species–area relationships to test the influence of the extent of alpine areas on regional richness, and mixed‐effects models to compare the effects of 12 spatial and environmental predictors. Variation in species composition was addressed by generalized dissimilarity models and by a coefficient of dispersal direction to assess historical links among regions. Results: Pool sizes were partially explained by current alpine areas, but the other predictors largely contributed to regional differences. The number of alpine species was influenced by area, calcareous bedrock, topographic heterogeneity and regional isolation, while non‐alpines responded better to connectivity and climate. Regional dissimilarity of alpine species was explained by isolation and precipitation, but non‐alpines only responded to isolation. Past dispersal routes were correlated with latitude, with alpine species showing stronger connections among regions. Main conclusions: Besides area effects, edaphic, topographic and spatio‐temporal determinants are important to understand the organization of regional species pools in alpine habitats. The number of alpine species is especially linked to refugia and isolation, but their composition is explained by past dispersal and post‐glacial environmental filtering, while non‐alpines are generally influenced by regional floras. New research on the dynamics of alpine biodiversity should contextualize the determinants of regional species pools and the responses of species with different ecological profiles. [ABSTRACT FROM AUTHOR]

Aim: Spatio‐temporal changes have likely caused range fragmentation and population isolation, which could have given rise to the observed current intraspecific differentiation in some species. Here, we test several hypotheses on the potential effect of Pleistocene glacial cycles in the diversification of Arctic shorebird species, comparing between different scenarios of fragmentation of the breeding distribution during glacial and interglacial periods. Location: Global. Taxon: Arctic migratory shorebirds. Methods: We performed species distribution models (SDMs) to explore the changes in the breeding and non‐breeding ranges of 69 species between the last glacial maximum (c. 21,000 years ago) and the present. We also included independent evidence from the fossil record and estimations on the potential extension of the tundra during glacial periods to validate the results from the SDMs. We assigned each species to one of four potential scenarios based on fragmentation and potential recolonization patterns of their breeding ranges during glaciations. Results: Our findings show that most of the species with subspecies experienced fragmentation of their ranges during the glacial, the interglacial or both periods. Meanwhile, the majority of the monotypic species maintained their ranges as a continuum. Moreover, the impacts of glacial cycles in the distribution were not homogeneous across the Arctic, and some regions were more prone to the fragmentation of breeding ranges than others. Main conclusions: Our work suggests that Pleistocene climatic cycles drove the diversification of Arctic shorebirds by creating allopatric breeding distributions. While the fragmentation of the breeding ranges occurred mainly during glacial periods, interglacials also played a part in maintaining or establishing newly isolated breeding populations for many species. Furthermore, species' distribution changes varied between different regions and habitats, which determined current shorebird diversity patterns. [ABSTRACT FROM AUTHOR]

The evolutionary processes driving patterns of genetic diversity and differentiation, and ultimately leading to speciation, are poorly understood. The aim of this thesis was to investigate the effects of environmental and biological mechanisms on gene flow and genetic diversity in the Bornean orang-utans, Specifically, I examined the effects of the Pleistocene climatic changes and riverine barriers as well as sex-biased dispersal. My results suggest that current Bornean orang-utan populations are the result of a recent radiation throughout the island, following the probable confinement within a glacial refugium in the Pleistocene. Furthermore, I found evidence for an extreme pattern of female philopatry and male-biased dispersal. These processes have led to highly structured genetic diversity, rendering the orangutans particularly vulnerable to anthropogenic effects and future climatic changes.

Abstract—The analysis of paleomagnetic data from Late Neoproterozoic complexes of Siberia and Australia is carried out. We show that the existing paleomagnetic datasets are in a disagreement with the concept of the axial-dipole configuration of the Late Neoproterozoic geomagnetic field: proposed non-actualistic models of the field do not reasonably explain the distribution of the paleomagnetic poles. We carried out analysis of paleomagnetic and virtual geomagnetic poles distribution based on simple geometric calculations. The analysis suggests that the configuration of the Late Neoproterozoic geomagnetic field was determined by the coexistence of a weak, long-lived source that was stably fixed in space, with a main dipole source that experienced sporadic multidirectional jumps within a certain preferred region of the Earth. Predominantly equatorial orientation of the main dipole source is substantiated by paleoclimate proxies. We propose a descriptive non-actualistic model of the Late Neoproterozoic geomagnetic field—the Devious Equatorial Dipole hypothesis, which brings paleomagnetic and paleoclimate data into accordance. [ABSTRACT FROM AUTHOR]

Aim: Historical climate variations, current climate and human impacts are known to influence current species richness, but their effects on phylogenetic and trait diversity have been seldom studied. We investigated the relationship of these three factors with the independent variations of species, phylogenetic and trait diversity of European mammals. Considering the position of the 0 ºC isotherm in the Last Glacial Maximum as a tipping point, we tested the following hypotheses: northern European assemblages host fewer species than southern European ones; northern areas harbour trait and phylogenetically clustered assemblages, while the more stable southern areas host random or overdispersed assemblages; and species richness correlates positively with human influence, while phylogenetic and trait diversity show clustered patterns in areas with stronger human influence. Location: Western Palaearctic. Time period: Current and Late Pleistocene effects on present‐day diversity. Major taxa studied: Terrestrial mammals. Methods: We used a novel analytical approach based on distance matrices to separate the independent variations of species, phylogenetic and trait diversity, and assessed their relationships with current climate, climate stability and human influence through structural equation models. Results: The species‐poor assemblages from northern Europe show higher phylogenetic and trait clustering than the more stable richer southern areas. However, no assemblage presented trait or phylogenetic overdispersion. Current climate is the primary driver of phylogenetic and trait diversity, while species richness is affected similarly by both current and past climates. Higher human influence correlates positively with species richness and trait diversity, both directly and by mediating indirect effects of present climate. Main conclusions: Current climate, climate stability and human influence affect the studied aspects of diversity, although the form and magnitude of their effects vary through space. Importantly, higher levels of human disturbances correlate with more species rich and trait diverse assemblages, an apparently counterintuitive result that deserves further study. [ABSTRACT FROM AUTHOR]

Pleistocene glaciations had a determining role for shaping the current distribution and diversity of organisms, especially in the Palearctic region. In this work, we carry out a phylogeographic analysis of Iberian and two Eastern European populations of the tiger beetle Calomera littoralis (Fabricius, 1787) in order to infer the processes that may have affected their evolutionary history. According to our results, the genetic diversity of central Iberian C. littoralis populations is very low. The haplotype networks also suggest that these populations experienced a genetic bottleneck in the past, possibly related to the last glacial maxima, similar to that observed in other cicindelid taxa. These results highlight the remarkable dispersal capacity of this species, being able to move freely from one locality to another, despite the relatively long distances of sub‐optimal habitat that separates them. The genetic data of central Iberian populations contrast with those of the Eastern European populations, with higher genetic diversity and no hints of any past bottleneck. This can be explained by the different characteristics of both (Iberian and Pontic) glacial refuges. The high degree of genetic differentiation between the three C. littoralis clades, and the inclusion of C. lunulata between them, suggests that the three analysed populations could be considered as different cryptic species. In that case, C. littoralis may correspond to a species complex that is still undergoing a process of speciation, similar to that observed in Cicindela campestris. [ABSTRACT FROM AUTHOR]

The species of the Parmelia saxatilis complex occurring in the Iberian Peninsula were revised. Eight species are accepted, including a new species found in southern Spain, described as P. rojoi A. Crespo, V. J. Rico & Divakar. The new species, which forms a sister-group relationship with P. saxatilis s. str., is rare in the Iberian Peninsula and is restricted to higher altitudes of northern and central Spain. Parmelia rojoi differs from P. saxatilis by generally narrower isidia and a more fragile thallus. The segregation of the new species is also supported by ITS (rDNA) and Mcm7 (MS456) phylogeny and multispecies coalescent-based approaches, including StarBEAST and BP&P. Furthermore, the divergence of P. rojoi is dated back to the Pleistocene, c. 2.13 Ma. A key to the identification of species from the P. saxatilis complex with their diagnostic features is provided. All species of the complex known from Europe are also found in the Iberian Peninsula. We hypothesize that P. rojoi is a relict species that survived the Pleistocene glaciations in refugia in Spain and has been unable to extend its distributional range in postglacial periods. [ABSTRACT FROM AUTHOR]

Background: The flat periwinkles, Littorina fabalis and L. obtusata, are two sister species widely distributed throughout the Northern Atlantic shores with high potential to inform us about the process of ecological speciation in the intertidal. However, whether gene flow has occurred during their divergence is still a matter of debate. A comprehensive assessment of the genetic diversity of these species is also lacking and their main glacial refugia and dispersal barriers remain largely unknown. In order to fill these gaps, we sequenced two mitochondrial genes and two nuclear fragments to perform a phylogeographic analysis of flat periwinkles across their distribution range. Results: We identified two main clades largely composed by species-specific haplotypes corresponding to L. obtusata and L. fabalis, with moderate to strong support, respectively. Importantly, a model of divergence with gene flow between the two species (from L. obtusata to L. fabalis) was better supported, both in Iberia and in northern-central Europe. Three mitochondrial clades were detected within L. fabalis and two within L. obtusata, with strong divergence between Iberia and the remaining populations. The largest component of the genetic variance within each species was explained by differences between geographic regions associated with these clades. Our data suggests that overall intraspecific genetic diversity is similar between the two flat periwinkle species and that populations from Iberia tend to be less diverse than populations from northern-central Europe. Conclusions: The phylogeographic analysis of this sister-species pair supports divergence with gene flow. This system thus provides us with the opportunity to study the contribution of gene flow and natural selection during diversification. The distribution of the different clades suggests the existence of glacial refugia in Iberia and northern-central Europe for both species, with a main phylogeographic break between these regions. Although the genetic diversity results are not fully conclusive, the lower diversity observed in Iberia could reflect marginal conditions at the southern limit of their distribution range during the current interglacial period. [ABSTRACT FROM AUTHOR]

We provide preliminary insights into the global phylogeographic and evolutionary patterns across species of the hydrozoan superfamily Plumularioidea (Cnidaria: Hydrozoa). We analyzed 1,114 16S sequences of 198 putative species of Plumularioidea collected worldwide. We investigated genetic connections and divergence in relation to present‐day and ancient biogeographic barriers, climate changes and oceanic circulation. Geographical distributions of most species are generally more constrained than previously assumed. Some species able to raft are dispersed widely. Human‐mediated dispersal explains some wide geographical ranges. Trans‐Atlantic genetic connections are presently unlikely for most of the tropical‐temperate species, but were probably more frequent until the Miocene–Pliocene transition, before restriction of the Tethys Sea and the Central American Seaway. Trans‐Atlantic colonizations were predominantly directed westwards through (sub)tropical waters. The Azores were colonized multiple times and through different routes, mainly from the east Atlantic, at least since the Pliocene. Extant geminate clades separated by the Isthmus of Panama have predominantly Atlantic origin. Various ancient colonizations mainly directed from the Indian Ocean to the Atlantic occurred through the Tethys Sea and around South Africa in periods of lower intensity of the Benguela upwelling. Thermal tolerance, population sizes, dispersal strategies, oceanic currents, substrate preference, and land barriers are important factors for dispersal and speciation of marine hydroids. [ABSTRACT FROM AUTHOR]

Abstract—Paleo- and rock magnetic, sedimentological, and isotope geochemical study is carried out for the carbonate member of Late Neoproterozoic Nichatka Formation (Siberian Platform, western slope of the Aldan Shield) enclosed within glacial deposits corresponding to the hypothetical event of "Snowball Earth" global glaciation. Based on the sedimentological, rock magnetic, and geochemical indications it is established that sediments composing this member have varve-type seasonal stratification and, according to our estimates, have been accumulated for at most 13 thousand years. Obtaining the detailed paleomagnetic data for the Precambrian varves allowed us to reveal a linear trend in the distribution of the virtual geomagnetic poles and to link it with the peculiarity of secular variation of the geomagnetic field during the time span of the Nichatka Formation. The paleomagnetic record in the periglacial sediments of the Nichatka Formation testifies to their deposition close to the equator which might be considered as supporting the Snowball Earth hypothesis. However, the absence of annual temperature fluctuations within the equatorial belt makes the formation of seasonal deposits at low latitudes barely possible and completely excludes such a possibility in the conditions close to total glaciation. The contradiction between paleoclimatic and paleomagnetic data is not explained in the context of the actualistic model of the geomagnetic field. The peculiarities of the paleomagnetic record in the Nichatka Formation, similar to the record of the field during the reversal, suggest that the geomagnetic field in the Neoproterozoic could be determined by substantial contribution of the low-latitude non-axial-dipole component. This peculiarity of the Neoproterozoic geomagnetic field can explain the entire set of the worldwide paleomagnetic data implying low latitude glaciations in the Neoproterozoic. [ABSTRACT FROM AUTHOR]

The passage of our Solar System through the spiral arms has been implicated as a contributor to global environmental perturbations. The suggestion of a consistent structure within the arms, informed by density wave theory, raises the possibility of repeating patterns of events at each arm crossing. Here we test the hypothesis that the structure of the arms of our galaxy influences the stratigraphic record on Earth. We construct independent structural and temporal models and combine these to compare the timings of arm tracers, materials from the earliest Solar System and events on Earth, including the largest extinctions. We find that a recurring sequence of events across the four arms emerges with an average arm-passing time of 188 million years. We suggest that the multiple temporal overlaps of events across arms, and their alignment with arm tracers and the earliest Solar System, presents an opportunity for a greater understanding of both Earth-based phenomena and galactic structure. Image 1 • A model of the galactic arms is combined with a temporal model derived from superchron ages. • A consistent sequence of regions of activity through different spiral arms is detected. • Effects on Earth include global glaciation and high extinctions. • The timing of events on Earth can be related directly to galactic arm tracers. • We suggest that galactic structure and Earth stratigraphy should be mutually informative. [ABSTRACT FROM AUTHOR]

The Smooth Hammerhead Shark Sphyrna zygaena is a species with anti-tropical distribution in the eastern Pacific from California USA, to southern Chile with a remarkably gap in abundance in equatorial areas between southern Mexico and Central America. For temperate species, warm waters can represent oceanographic barriers limiting the gene flow between adjacent populations. The mtDNA control region was used to infer the phylogeography and historical demography of the Smooth Hammerhead in the eastern Pacific. An AMOVA comparing locations grouped into northern and southern eastern Pacific equatorial areas indicated significant genetic differentiation. Each population had a common haplotype separated by two mutational differences suggesting that divergence occurred very recently. The pattern of genetic differences matches with the anti-tropical distribution of S. zygaena in the eastern Pacific. Gene diversity was lower in the northern population when compared to the southern area, a pattern indicative of a recent founder event. Broadly, this pattern suggests a recent population expansion occurring 25,000–10,000 years. bp, during the last glacial cycle, when the drop of surface sea temperatures created favorable conditions at equatorial latitudes to cross the thermal barrier imposed by warm waters at equatorial latitudes. These genetically distinct population groups might lead to delineate a management plan that considers two separated stocks in the eastern Pacific. [ABSTRACT FROM AUTHOR]