scholarly journals Reconstruction of past distribution for the Mongolian toad, Strauchbufo raddei (Anura: Bufonidae) using environmental modeling

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9216
Author(s):  
Spartak N. Litvinchuk ◽  
Natalya A. Schepina ◽  
Amaël Borzée
Keyword(s):  
Life Time ◽  
Environmental Modeling ◽  
Climatic Conditions ◽  
Ecological Requirements ◽  
Time Period ◽  
Extant Species ◽  
The One ◽  
The Last Glacial Maximum ◽  
Over Time ◽  
The Last Glacial

The use of ecological models enables determining the current distribution of species, but also their past distribution when matching climatic conditions are available. In specific cases, they can also be used to determine the likelihood of fossils to belong to the same species—under the hypothesis that all individuals of a species have the same ecological requirements. Here, using environmental modeling, we reconstructed the distribution of the Mongolian toad, Strauchbufo raddei, since the Last Glacial Maximum and thus covering the time period between the Late Pleistocene and the Holocene. We found the range of the species to have shifted over time, with the LGM population clustered around the current southern range of the species, before expanding east and north during the Pleistocene, and reaching the current range since the mid-Holocene. Finally, we determined that the ecological conditions during the life-time of the mid-Pleistocene fossils attributed to the species in Europe were too different from the one of the extant species or fossils occurring at the same period in Asia to belong to the same species.

scholarly journals High-Resolution Marine Record of Climatic Change in Mid-latitude Chile during the Last 28,000 Years Based on Terrigenous Sediment Parameters

1999 ◽  
Vol 51 (1) ◽  
pp. 83-93 ◽  
Author(s):  
Frank Lamy ◽  
Dierk Hebbeln ◽  
Gerold Wefer
Keyword(s):  
Sediment Cores ◽  
Climatic Conditions ◽  
Sediment Supply ◽  
Size Distributions ◽  
Terrigenous Sediment ◽  
Latitudinal Position ◽  
Grain Size Distributions ◽  
The Last Glacial Maximum ◽  
Southern Westerlies ◽  
The Last Glacial

AbstractMarine sediment cores from the continental slope off mid-latitude Chile (33°S) were studied with regard to grain-size distributions and clay mineral composition. The data provide a 28,000-yr14C accelerator mass spectrometry-dated record of variations in the terrigenous sediment supply reflecting modifications of weathering conditions and sediment source areas in the continental hinterland. These variations can be interpreted in terms of the paleoclimatic evolution of mid-latitude Chile and are compared to existing terrestrial records. Glacial climates (28,000–18,000 cal yr B.P.) were generally cold–humid with a cold–semiarid interval between 26,000 and 22,000 cal yr B.P. The deglaciation was characterized by a trend toward more arid conditions. During the middle Holocene (8000–4000 cal yr B.P.), comparatively stable climatic conditions prevailed with increased aridity in the Coastal Range. The late Holocene (4000–0 cal yr B.P.) was marked by more variable paleoclimates with generally more humid conditions. Variations of rainfall in mid-latitude Chile are most likely controlled by shifts of the latitudinal position of the Southern Westerlies. Compared to the Holocene, the southern westerly wind belt was located significantly farther north during the last glacial maximum. Less important variations of the latitudinal position of the Southern Westerlies also occurred on shorter time scales.

scholarly journals Chronological Distribution of Brazilian Glyptodon SP. Remains: A Direct 14C Date for a Specimen from Iporanga, São Paulo, Brazil

Radiocarbon ◽  
2011 ◽  
Vol 53 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Alex Hubbe ◽  
André G Vasconcelos ◽  
Luciano Vilaboim ◽  
Ivo Karmann ◽  
Walter Neves
Keyword(s):  
Mass Spectrometry ◽  
South America ◽  
Last Glacial Maximum ◽  
Accelerator Mass Spectrometry ◽  
Radiocarbon Dating ◽  
Sao Paulo ◽  
São Paulo ◽  
The One ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Glyptodon sp. fossil remains can be found throughout Brazil. However, little information is available about their chronological distribution. With the intention to contribute to this issue, we present, as far as we know, the first direct radiocarbon date for 1 specimen of this genus found in Brazil. The osteoderm MZSP-PV660 found in Abismo do Fóssil Cave (SP-145), Iporanga, São Paulo, Brazil, was dated by accelerator mass spectrometry at the Beta Analytic Radiocarbon Dating Laboratory. The 14C date obtained was between 20,680 and 21,370 calibrated years before the present. Unfortunately, the scant (and often imprecise or unreliable) chronological data regarding this species and genus in Brazil and elsewhere in South America precludes a robust comparison among the dates available and the one presented here. Nevertheless, our finding supports the existence of this genus in South America at least until the Last Glacial Maximum.

scholarly journals The Legacy of Recurrent Introgression during the Radiation of Hares

2020 ◽  
Author(s):  
Mafalda S Ferreira ◽  
Matthew R Jones ◽  
Colin M Callahan ◽  
Liliana Farelo ◽  
Zelalem Tolesa ◽  
...  
Keyword(s):  
Incomplete Lineage Sorting ◽  
Introgressive Hybridization ◽  
Lineage Sorting ◽  
Whole Exome ◽  
Extant Species ◽  
The Last Glacial Maximum ◽  
Shared Genetic ◽  
The Last Glacial ◽  
Shared Variation

Abstract Hybridization may often be an important source of adaptive variation, but the extent and long-term impacts of introgression have seldom been evaluated in the phylogenetic context of a radiation. Hares (Lepus) represent a widespread mammalian radiation of 32 extant species characterized by striking ecological adaptations and recurrent admixture. To understand the relevance of introgressive hybridization during the diversification of Lepus, we analyzed whole exome sequences (61.7 Mb) from 15 species of hares (1- 4 individuals per species), spanning the global distribution of the genus, and two outgroups. We used a coalescent framework to infer species relationships and divergence times, despite extensive genealogical discordance. We found high levels of allele sharing among species and show that this reflects extensive incomplete lineage sorting and temporally layered hybridization. Our results revealed recurrent introgression at all stages along the Lepus radiation, including recent gene flow between extant species since the last glacial maximum, but also pervasive ancient introgression occurring since near the origin of the hare lineages. We show that ancient hybridization between northern hemisphere species has resulted in shared variation of potential adaptive relevance to highly seasonal environments, including genes involved in circadian rhythm regulation, pigmentation, and thermoregulation. Our results illustrate how the genetic legacy of ancestral hybridization may persist across a radiation, leaving a long-lasting signature of shared genetic variation that may contribute to adaptation.

The impact of climate changes during the Holocene on vegetation in northern French Guiana

2010 ◽  
Vol 73 (2) ◽  
pp. 220-225 ◽  
Author(s):  
Vincent Freycon ◽  
Marion Krencker ◽  
Dominique Schwartz ◽  
Robert Nasi ◽  
Damien Bonal
Keyword(s):  
Amazon Basin ◽  
French Guiana ◽  
Climatic Conditions ◽  
Tropical Rainforests ◽  
The Holocene ◽  
Forest Sites ◽  
Vertical Variations ◽  
The Impact ◽  
The Last Glacial Maximum ◽  
The Last Glacial

The impact of climatic changes that occurred during the last glacial maximum and the Holocene on vegetation changes in the Amazon Basin and the Guiana Shield are still widely debated. The aim of our study was to investigate whether major changes in vegetation (i.e. transitions between rainforests and C4 savannas) occurred in northern French Guiana during the Holocene. We measured variations in the ä13C of soil organic matter at eight sites now occupied by forest or savannah. The forest sites were selected to cover two regions (forest refugia and peneplains) which are thought to have experienced different intensities of disturbance during the latest Pleistocene and the Holocene. We found that none of the forest sites underwent major disturbances during the Holocene, i.e. they were not replaced by C4 savannahs or C4 forest savannahs for long periods. Our results thus suggest that tropical rainforests in northern French Guiana were resilient to drier climatic conditions during the Holocene. Nevertheless, geographical and vertical variations in the 13C of SOM were compatible with minor changes in vegetation, variations in soil processes or in soil physical properties.

scholarly journals The legacy of recurrent introgression during the radiation of hares

2020 ◽  
Author(s):  
Mafalda S. Ferreira ◽  
Matthew R. Jones ◽  
Colin M. Callahan ◽  
Liliana Farelo ◽  
Zelalem Tolesa ◽  
...  
Keyword(s):  
Incomplete Lineage Sorting ◽  
Introgressive Hybridization ◽  
Lineage Sorting ◽  
Whole Exome ◽  
Extant Species ◽  
The Last Glacial Maximum ◽  
Shared Genetic ◽  
The Last Glacial ◽  
Shared Variation

AbstractHybridization may often be an important source of adaptive variation, but the extent and long-term impacts of introgression have seldom been evaluated in the phylogenetic context of a radiation. Hares (Lepus) represent a widespread mammalian radiation of 32 extant species characterized by striking ecological adaptations and recurrent admixture. To understand the relevance of introgressive hybridization during the diversification of Lepus, we analyzed whole exome sequences (61.7 Mb) from 15 species of hares (1- 4 individuals per species), spanning the global distribution of the genus, and two outgroups. We used a coalescent framework to infer species relationships and divergence times, despite extensive genealogical discordance. We found high levels of allele sharing among species and show that this reflects extensive incomplete lineage sorting and temporally layered hybridization. Our results revealed recurrent introgression at all stages along the Lepus radiation, including recent gene flow between extant species since the last glacial maximum, but also pervasive ancient introgression occurring since near the origin of the hare lineages. We show that ancient hybridization between northern hemisphere species has resulted in shared variation of potential adaptive relevance to highly seasonal environments, including genes involved in circadian rhythm regulation, pigmentation, and thermoregulation. Our results illustrate how the genetic legacy of ancestral hybridization may persist across a radiation, leaving a long-lasting signature of shared genetic variation that may contribute to adaptation within and among species.

scholarly journals Forbidden islands. The absence of endemics among the insular non-volant terrestrial mammalian fauna of the Red Sea

2015 ◽  
Vol 2 (2) ◽  
pp. 101 ◽  
Author(s):  
Marco Masseti ◽  
Giuseppe De Marchi ◽  
Giorgio Chiozzi
Keyword(s):  
Red Sea ◽  
Marine Species ◽  
Climatic Conditions ◽  
Eastern Africa ◽  
Mammalian Fauna ◽  
Additional Species ◽  
Terrestrial Biodiversity ◽  
Almost All ◽  
The Last Glacial Maximum ◽  
The Last Glacial

The Red Sea is a land-locked sea that is globally significant in terms of the unique biodiversity and endemism of its marine species. In contrast, the terrestrial biodiversity on its islands is poor and mainly composed of species present also on the mainland. To profile the non-volant terrestrial mammalian fauna, we reviewed all available records in the literature and report some recent captures; in particular, we point out two additional species from the Dahlak archipelago: the Northeast African spiny mouse (<em>Acomys cahirinus</em>) and a still undetermined shrew (<em>Crocidura</em> sp.). As far as we know, the only endemic vertebrates are three species of snake (Squamata, Serpentes) and perhaps one gazelle (<em>Gazella arabica</em>). The composition of the insular mammalian fauna of the Red Sea is olygotypic, consisting of only a few taxa, mostly anthropochorous, that are shared with the mainland of eastern Africa and/or western Arabia, and which are repeated monotonously on the few islands inhabited by mammals. A lack of endemic mammals can be explained as the result of the only recent connection of almost all the islands with the mainland during the Last Glacial Maximum and by the harsh climatic conditions that allow the survival of only a few xeric specialists.

scholarly journals Paleoproductivity changes during the Late Quaternary in the southeastern Brazilian upper continental margin of the Southwestern Atlantic

2010 ◽  
Vol 58 (spe1) ◽  
pp. 31-41 ◽  
Author(s):  
Renata Hanae Nagai ◽  
Silvia Helena de Mello e Sousa ◽  
Rafael André Lourenço ◽  
Márcia Caruso Bícego ◽  
Michel Michaelovitch de Mahiques
Keyword(s):  
Sea Level ◽  
Continental Margin ◽  
Late Quaternary ◽  
Climatic Conditions ◽  
Continental Margins ◽  
The Holocene ◽  
Sea Level Fluctuations ◽  
Brazil Current ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Changes in the Brazilian continental margins oceanic productivity and circulation over the last 27,000 years were reconstructed based on sedimentological and microfaunal analyses. Our results suggest that oceanic paleoproductivity and the supply of terrigenous sediments to the Brazilian continental margin were higher during the Last Glacial Maximum (LGM) than during the Holocene. These changes may have been primarily influenced by significant sea level fluctuations that have occurred since the late Pleistocene. During the LGM, the lower sea level, higher productivity and lower sea-surface paleotemperatures may have been the result of the offshore displacement of the main flow of the Brazil Current. However, during the Holocene, the warm waters of the Brazil Current were displaced toward the coast. This displacement contributed to the increase in water temperature and prevented an increase in oceanic productivity. The decrease in terrigenous supply since the LGM could be related to the increase of the extension of the continental shelf and/or drier climatic conditions.

Fossil Arthropods from a Full-Glacial Site in Northeastern Italy

1994 ◽  
Vol 41 (3) ◽  
pp. 336-342 ◽  
Author(s):  
Donatella Foddai ◽  
Alessandro Minelli
Keyword(s):  
Ground Beetle ◽  
Glacial Maximum ◽  
Peat Bogs ◽  
Insect Fauna ◽  
Ecological Requirements ◽  
Northeastern Italy ◽  
The Alps ◽  
The Last Glacial Maximum ◽  
July Temperature ◽  
The Last Glacial

AbstractFossil remains of beetles and oribatid mites from a peat deposit dated 18,870 ± 300 yr B.P. near Verona, northeastern Italy, represent the first insect fauna of its kind from the last glacial maximum to be described from Italy. The assemblage includes the ground beetle Amara alpina, whose distribution today in Europe is restricted to mountains in Scandinavia and Scotland. Ecological requirements and geographic distribution of recent populations of the identified species suggest mesic habitats with standing water and peat bogs during the glacial maximum. The paleoenvironment was comparable to present-day lowland moors in Scandinavia or mesic environments above 1000 m altitude on the southern slopes of the Alps. The climate is inferred to have been colder and wetter than today. Mean July temperature may have been 8-9°C lower than at present.

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