Search results for "Fossil"

Comment on “An early Late Triassic long-necked reptile with a bony pectoral shield and gracile appendages” by Jerzy Dzik and Tomasz Sulej

2017

Comment on “An early Late Triassic long-necked reptile with a bony pectoral shield and gracile appendages” by Jerzy Dzik and Tomasz Sulej

Environmental drivers and abrupt changes of phytoplankton community in temperate lake Lielais Svētiņu, Eastern Latvia, over the last Post-Glacial per…

2021

Understanding the long-term dynamics of ecological communities on the centuries-to-millennia scale is important for explaining the emergence of present-day biodiversity patterns and for predicting possible future scenarios. Fossil pigments and ancient DNA present in various sedimentary deposits can be analysed to study long-term changes in ecological communities. We analysed recent compilations of data, including fossil pigments, microfossils, and molecular inventories from the sedimentary archives, to understand the impact of gradual versus abrupt climate changes on the ecosystem status of a regional model lake over the last ~14.5 kyr. Such long and complete paleo-archives are scarce in No…

The seasonal water temperature cycle in the Arctic Dicksonfjord (Svalbard) during the Holocene Climate Optimum derived from subfossil Arctica islandi…

2015

Future climate change will have significant effects on ecosystems worldwide and on polar regions in particular. Hence, palaeo-environmental studies focussing on the last warmer-than-today phase (i.e. the early Holocene) in higher latitudes are of particular importance to understand climate development and its potential impact in polar systems. Molluscan bivalve shells constitute suitable bio-archives for high-resolution palaeo-environmental reconstructions. Here, we present a first reconstruction of early Holocene seasonal water temperature cycle in an Arctic fjord based on stable oxygen isotope (δ18Oshell) profiles in shells of Arctica islandica (Bivalvia) from raised beach deposits in Di…

Last Millennium hydro-climate variability in Central–Eastern Europe (Northern Carpathians, Romania)

2015

Proxy-based reconstructions of climate variability over the last millennium provide important insights for understanding current climate change within a long-term context. Past hydrological changes are particularly difficult to reconstruct, yet rainfall patterns and variability are among the most critical environmental variables. Ombrotrophic bogs, entirely dependent on water from precipitation and sensitive to changes in the balance between precipitation and evapotranspiration, are highly suitable for such hydro-climate reconstructions. We present a multi-proxy analysis (testate amoebae, plant macrofossils, stable carbon isotopes in Sphagnum, pollen, spores and macroscopic charcoal) from …

2017

Ranking among the largest volcanic eruptions of the Common Era (CE), the ‘Millennium Eruption’ of Changbaishan produced a widely-dispersed tephra layer (known as the B-Tm ash), which represents an important tie point for palaeoenvironmental studies in East Asia. Hitherto, there has been no consensus on its age, with estimates spanning at least the tenth century CE. Here, we identify the cosmogenic radiocarbon signal of 775 CE in a subfossil larch engulfed and killed by pyroclastic currents emplaced during the initial rhyolitic phase of the explosive eruption. Combined with glaciochemical evidence from Greenland, this enables us to date the eruption to late 946 CE. This secure date rules out…

Climate controls on the Holocene development of a subarctic lake in northern Fennoscandia

2015

International audience; Climate exerts strong control over the functioning of northern freshwater ecosystems, yet their resilience and responses to climate forcing may vary. We examined postglacial development patterns in subarctic Lake Varddoaijavri to discern the impact of direct climate controls, catchment influence, and ontogenic processes on the ecological functioning of the lake over the Holocene. Subfossil diatom assemblages together with the elemental and stable isotopic (delta C-13, delta N-15) composition of sediment organic matter were used to examine climate-induced changes in the structure of the phototrophic community and transport of terrestrial organic matter from the catchm…

Pullneyocoris dentatus gen. et sp. nov. (Hemiptera: Pentatomoidea: Cydnidae), the third representative of the subfamily Amnestinae from mid-Cretaceou…

2020

Abstract A new genus and species of burrower bug, Pullneyocoris dentatus gen. et sp. nov. (Hemiptera: Cydnidae: Amnestinae), is described from amber of northern Myanmar. It is the third representative of this family known from Burmese amber, and besides its autapomorphies, it presents a mixture of characters relevant to the extant Parachilocoris Horvath, 1919 and Pullneya Horvath, 1919. A comparison of this new genus to the two genera already described from the burmite, i.e. Chilamnestocoris Lis J.A., Lis. B. & Heiss, 2018, and Punctacorona Wang, Du, Yao & Ren, 2019 is also provided.

Presence of Naraoia Walcott, 1912 in the middle Cambrian of Europe (Murero, NE Spain).

2018

Este artículo se encuentra disponible en la página web de la revista en la siguiente URL: http://sepaleontologia.es/revista/anteriores/SJP%20(2018)%20vol.%2033/vol.%201/04.pdf The genus Naraoia Walcott, 1912, a Burgess Shale-type fossil known from the lower and middle Cambrian of British Columbia (Canada), Idaho and Utah (USA), as well as from Yunnan and Guizhou provinces (China), is now reported from the middle Cambrian of Murero (Zaragoza, Spain), which is the first record in the Acadobaltic province. The only fragmented specimen found is determined as Naraoia sp., its age being Pardailhania multispinosa Zone (Drumian Stage). This new datum reinforces the hypothesis of the existence of a …

The Role of Recent Admixture in Forming the Contemporary West Eurasian Genomic Landscape

2015

Summary Over the past few years, studies of DNA isolated from human fossils and archaeological remains have generated considerable novel insight into the history of our species. Several landmark papers have described the genomes of ancient humans across West Eurasia, demonstrating the presence of large-scale, dynamic population movements over the last 10,000 years, such that ancestry across present-day populations is likely to be a mixture of several ancient groups [1, 2, 3, 4, 5, 6, 7]. While these efforts are bringing the details of West Eurasian prehistory into increasing focus, studies aimed at understanding the processes behind the generation of the current West Eurasian genetic landsc…

Investigating the influence of climate changes on rodent communities at a regional-scale (MIS 1-3, southwestern France).

2016

25 pages; International audience; Terrestrial ecosystems have continuously evolved throughout the Late Pleistocene and theHolocene, deeply affected by both progressive environmental and climatic modifications, aswell as by abrupt and large climatic changes such as the Heinrich or Dansgaard-Oeschgerevents. Yet, the impacts of these different events on terrestrial mammalian communities arepoorly known, as is the role played by potential refugia on geographical species distributions.This study examines community changes in rodents of southwestern France between50 and 10 ky BP by integrating 94 dated faunal assemblages coming from 37 archaeologicalsites. This work reveals that faunal distributi…