A Holocene floodplain sequence from the Kirenga Valley, Lake Baikal region (Siberia), and its significance for molluscan and mammalian biogeography

The archaeological record in the Baikal region is characterised by a marked discontinuity separating different groups of hunter-gatherers within the Neolithic period. A range of sedimentary archives has been studied to investigate this issue and whether it had an environmental cause. Our focus has been on floodplain sequences from river valleys, which can augment other higher resolution records such as those from lakes. Here we report on the molluscs and small vertebrates recovered from a Holocene floodplain sequence at a remote locality (Krasniy Yar XI) in the Kirenga Valley, in the Lake Baikal region of eastern Siberia. The sequence lacked the necessary temporal resolution to adequately address this archaeological question, but it did provide a valuable radiocarbon-dated record of local floodplain pedogenesis, molluscs and vertebrates over the last ∼7000 cal yr BP. Aquatic molluscs are more frequent during the early part of the record but they become scarce in the upper levels, which are dominated by land snails, especially species of Vallonia. Other noteworthy species include Vertigo microsphaera, recently discovered living in the area, and the first fossil records of V. kushiorensis, V. chytryi, and V. genesioides from the Baikal region. An exceptional feature of the molluscan record was the relatively high frequency of sinistral specimens of Cochlicopa, which occurred in 12/18 samples with a mean frequency of 9.8% (38/385). The vertebrates included specimens of southern birch mouse Sicista subtilis, unknown living in this part of Siberia with the closest records some 400 km to the southwest. These data demonstrate marked faunal and distributional shifts within the Holocene, reflecting local and regional environmental changes through time

Plio-Pleistocene climatic change had a major impact on the assembly and disassembly processes of Iberian rodent communities

Comprehension of changes in community composition through multiple spatio-temporal scales is a prime challenge in ecology and palaeobiology. However, assembly, structuring and disassembly of biotic metacommunities in deep-time is insufficiently known. To address this, we used the extensively sampled Iberian Plio-Pleistocene fossil record of rodent faunas as our model system to explore how global climatic events may alter metacommunity structure. Through factor analysis, we found five sets of genera, called faunal components, which co-vary in proportional diversity over time. These faunal components had different spatio-temporal distributions throughout the Plio-Pleistocene, resulting in non-random changes in species assemblages, particularly in response to the development of the Pleistocene glaciations. Three successive metacommunities with distinctive taxonomic structures were identified as a consequence of the differential responses of their members to global climatic change: (1) Ruscinian subtropical faunas (5.3–3.4 Ma) dominated by a faunal component that can be considered as a Miocene legacy; (2) transition faunas during the Villafranchian–Biharian (3.4–0.8 Ma) with a mixture of different faunal components; and (3) final dominance of the temperate Toringian faunas (0.8–0.01 Ma) that would lead to the modern Iberian assemblage. The influence of the cooling global temperature drove the reorganisation of these rodent metacommunities. Selective extinction processes due to this large-scale environmental disturbance progressively eliminated the subtropical specialist species from the early Pliocene metacommunity. This disassembly process was accompanied by the organisation of a diversified metacommunity with an increased importance of biome generalist species, and finally followed by the assembly during the middle–late Pleistocene of a new set of species specialised in the novel environments developed as a consequence of the glaciations

Reconciling the stratigraphy and depositional history of the Lycian orogen-top basins, SW Anatolia

Terrestrial fossil records from the SWAnatolian basins are crucial both for regional correlations and palaeoenvironmental reconstructions. By reassessing biostratigraphic constraints and incorporating new fossil data, we calibrated and reconstructed the late Neogene andQuaternary palaeoenvironments within a regional palaeogeographical framework. The culmination of the Taurides inSWAnatolia was followed by a regional crustal extension from the late Tortonian onwards that created a broad array of NE-trending orogen-top basins with synchronic associations of alluvial fan, fluvial and lacustrine deposits. The terrestrial basins are superimposed on the upper Burdigalian marine units with a c. 7 myr of hiatus that corresponds to a shift from regional shortening to extension. The initial infill of these basins is documented by a transition from marginal alluvial fans and axial fluvial systems into central shallow-perennial lakes coinciding with a climatic shift from warm/humid to arid conditions. The basal alluvial fan deposits abound in fossil macro-mammals of an early Turolian (MN11–12; late Tortonian) age. The Pliocene epoch in the region was punctuated by subhumid/humid conditions resulting in a rise of local base levels and expansion of lakes as evidenced by marsh-swamp deposits containing diverse fossilmammal assemblages indicating late Ruscinian (lateMN15; late Zanclean) ageWe are grateful for the support of the international bilateral project between The Scientific and Technological Research Council of Turkey (TUBITAK) and The Russian Scientific Foundation (RFBR) with grant a number of 111Y192. M.C.A. is grateful to the Turkish Academy of Sciences (TUBA) for a GEBIP (Young Scientist Award) grant. T.K. and S.M. are grateful to the Ege University Scientific Research Center for the TTM/002/2016 and TTM/001/2016 projects. M.C.A., H.A., S.M. and M.B. have obtained Martin and Temmick Fellowships at Naturalis Biodiversity Center (Leiden). F.A.D. is supported by a Mehmet Akif Ersoy University Scientific Research Grant. T.A.N. is supported by an Alexander-von-Humboldt Scholarship. L.H.O. received support from TUBITAK under the 2221 program for visiting scientists

Aminostratigraphical test of the East European Mammal Zonation for the late Neogene and Quaternary

An aminostratigraphical study was undertaken to provide an independent test of the veracity of the East European Mammal zonation. This important biostratigraphical scheme was originally defined from reference sites in the Azov/Black Sea region of southern Russia, but is now widely used to correlate late Neogene and Quaternary sediments across much of Europe and western Asia. As well as yielding a series of mammal assemblages, these reference sites, which range in age from the late Pliocene (Piacenzian ca. 3.0 Ma) to Late Pleistocene (0.1 Ma), also contain calcitic opercula of two genera (Bithynia and Parafossarulus) of freshwater gastropod snails that are suitable for amino acid dating. The intra-crystalline protein decomposition (IcPD) of four amino acids (aspartic acid, alanine, valine, and glutamic acid) was analysed from the opercula of these two genera, which showed similar patterns of protein degradation, allowing both to be used for aminostratigraphy. The IcPD data are consistent with the relative ages inferred from the mammal biostratigraphy and also with stratigraphical hiatuses interpreted from the fossil record. The temporal resolution provided by IcPD data from opercula is amino acid dependent, and declines in samples older than ∼2 Ma. The high variability of IcPD between opercula samples at some sites suggests reworking. Anomalously high levels of IcPD in samples from the Early Pleistocene site of Tizdar may be due to geothermal heating from local mud volcanism. This study provides the first large-scale application of IcPD-based aminostratigraphy for the Quaternary of continental Europe, and highlights its importance in testing regional stratigraphic schemes for the Late Pliocene and the Pleistocene

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WOS: 000426022800040Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [111Y192]; Russian Foundation for Basic Research (RFBR)Russian Foundation for Basic Research (RFBR) [111Y192]; Turkish Academy of Sciences (TUBA)Turkish Academy of SciencesThe authors are grateful to the support of the international bilateral project between The Scientific and Technological Research Council of Turkey (TUBITAK) and The Russian Foundation for Basic Research (RFBR) with grant number of 111Y192. We are grateful to J.D. Gardner (Royal Tyrrell Museum of Palaeontology) for reading and improving an earlier version of the manuscript. M.C. Alcicek is indebted to the GEBIP grant (The Outstanding Young Scientist Award) given by the Turkish Academy of Sciences (TUBA)