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Maul L.C.,Senckenberg Research Station of Quaternary Palaeontology | Masini F.,University of Palermo | Parfitt S.A.,University College London | Parfitt S.A.,Natural History Museum in London | And 2 more authors.
Quaternary Science Reviews | Year: 2014

The study of evolutionary rates dates back to the work of Simpson and Haldane in the 1940s. Small mammals, especially Plio-Pleistocene arvicolids (voles and lemmings), are particularly suited for such studies because they have an unusually complete fossil record and exhibit significant evolutionary change through time. In recent decades, arvicolids have been the focus of intensive research devoted to the tempo and mode of evolutionary change and the identification of trends in dental evolution that can be used to correlate and date fossil sites. These studies have raised interesting questions about whether voles and lemmings had unique evolutionary trajectories, or show convergent evolutionary patterns with other hypsodont rodents. Here we review evolutionary patterns in selected arvicolid lineages and endemic Messinian murids (Mikrotia spp.) and discuss reasons for convergence in dental morphology in these two groups of hypsodont rodents. The results substantiate previously detected patterns, but the larger dataset shows that some trends are less regular than previous studies have suggested. With the exception of a pervasive and sustained trend towards increased hypsodonty, our results show that other features do not follow consistent patterns in all lineages, exhibiting a mosaic pattern comprising stasis, variable rate evolution and gradual unidirectional change through time. Evidence for higher evolutionary rates is found in lineages apparently undergoing adaptations to new ecological niches. In the case of Mikrotia, Microtus voles and the water vole (Mimomys-A. rvicola) lineage, a shift to a fossorial lifestyle appears to have been an important driving force in their evolution. For other characters, different causes can be invoked; for example a shift to a semi-aquatic lifestyle may be responsible for the trend towards increasing size in Arvicola. Biochronological application of the data should take into account the complexity and biases of the data. © 2013 Elsevier Ltd.


Menzel P.,University of Hamburg | Gaye B.,University of Hamburg | Wiesner M.G.,University of Hamburg | Prasad S.,German Research Center for Geosciences | And 5 more authors.
Limnology and Oceanography | Year: 2013

Lonar Lake is a eutrophic, saline soda lake with permanently anoxic deep water. The high pH and deoxygenation result in very elevated δ15N of suspended particulate matter (SPM) and sediments due to denitrification and pH-related loss of gaseous ammonium. SPM and sinking particles are predominantly aquatic in origin, whereas surface sediments are of mixed terrestrial plant and planktonic source. An indicator of degradation intensity was derived from a principal component analysis of the spectral distribution of amino acids and named Lonar degradation index (LI). A ratio of individual amino acids (Ox: Anox ratio) was additionally used to determine the relative degree of aerobic vs. anaerobic degradation. These two biogeochemical indicators can be used to detect changes in degradation intensity and redox conditions in the geological history, and thus the paleoclimatic interpretation of Lonar sediments. Surface sediments can be divided into three zones: (1) a nearshore, oxic zone of predominantly aquatic organic matter, in which oxidation leads to a strong diagenetic increase of δ15N; (2) an alluvial zone with a predominance of isotopically depleted land plant and soil organic matter degraded under oxic conditions; and (3) an anoxic, deep zone, which receives aquatic organic matter and land plant-derived material transported near the bottom and in which organic matter is well preserved due to anoxic diagenetic conditions. © 2013, by the Association for the Sciences of Limnology and Oceanography, Inc.


Menzel P.,University of Hamburg | Gaye B.,University of Hamburg | Mishra P.K.,Helmholtz Center Potsdam | Anoop A.,Helmholtz Center Potsdam | And 8 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2014

We present the results of biogeochemical and mineralogical analyses on a sediment core that covers the Holocene sedimentation history of the climatically sensitive, closed, saline, and alkaline Lonar Lake in the core monsoon zone in central India. We compare our results of C/N ratios, stable carbon and nitrogen isotopes, grain-size, as well as amino acid derived degradation proxies with climatically sensitive proxies of other records from South Asia and the North Atlantic region. The comparison reveals some more or less contemporaneous climate shifts. At Lonar Lake, a general long term climate transition from wet conditions during the early Holocene to drier conditions during the late Holocene, delineating the insolation curve, can be reconstructed. In addition to the previously identified periods of prolonged drought during 4.6-3.9 and 2.0-0.6 cal ka that have been attributed to temperature changes in the Indo Pacific Warm Pool, several additional phases of shorter term climate alteration superimposed upon the general climate trend can be identified. These correlate with cold phases in the North Atlantic region. The most pronounced climate deteriorations indicated by our data occurred during 6.2-5.2, 4.6-3.9, and 2.0-0.6 cal ka BP. The strong dry phase between 4.6 and 3.9. cal. ka BP at Lonar Lake corroborates the hypothesis that severe climate deterioration contributed to the decline of the Indus Civilisation about 3.9 ka BP. © 2014 Elsevier B.V.


Maul L.C.,Senckenberg Research Station of Quaternary Palaeontology | Bruch A.A.,Senckenberg Institute | Smith K.T.,Senckenberg Research Station of Quaternary Palaeontology | Shenbrot G.,Ben - Gurion University of the Negev | And 2 more authors.
Quaternary International | Year: 2015

Microvertebrates are generally well suited for drawing inferences on past environmental conditions because they are closely bound to the areas in which they lived. In this paper, we discuss palaeoecological implications of two microvertebrate concentrations in the Middle Pleistocene site Qesem Cave in Israel. The ecological preferences of the nearest living relatives of the microvertebrate taxa recorded in Concentration 1 (squares L-N/13-15) and 2 (squares G-H/16-17) at Qesem Cave allow us to infer a mosaic of open palaeoenvironment with sparse vegetation, shrubland, Mediterranean Forest, rocky areas and riverbanks. Additionally, we infer palaeoclimate from the bioclimatic distribution of extant species using the Coexistence Approach. To our knowledge, this is the first time the approach has been applied to microfaunal assemblages. These data suggest cooler and slightly drier winters and somewhat lower seasonality than at present around Qesem Cave; the differences are more pronounced for the time covered by Concentration 2 than Concentration 1.Among microvertebrates, micromammals are most suitable for biostratigraphic purposes. With the exception of Rattus cf. haasi and the Myomimus judaicus/. setzeri group, the small mammal fauna of Qesem Cave comprises only taxa that live today in the Levant. R. haasi and M. judaicus have been found in Israel in the Early and Middle Pleistocene, and their latest known record was from the Acheulian site of Oumm Qatafa. Their presence in Qesem Cave extends the previously known stratigraphic range of these species. The absence of R. haasi in Mousterian sites is thus consistent with the pre-Mousterian age of Qesem Cave. Morphometric data on molars of Guenther's Vole show that the lineage segment preserved in Concentration 2 is more primitive than in Concentration 1, indicating that the former concentration is older. The evolutionary level of the sample from Qesem Concentration 1 is similar to Tabun D (boundary of Acheulo-Yabrudian Cultural Complex and Mousterian), and that from Qesem Concentration 2 similar to Tabun Eb (Acheulo-Yabrudian). © 2015 Elsevier Ltd and INQUA.


Prieto J.,Ludwig Maximilians University of Munich | Angelone C.,Autonomous University of Barcelona | Casanovas-Vilar I.,Autonomous University of Barcelona | Gross M.,Universalmuseum Joanneum | And 4 more authors.
Palaeobiodiversity and Palaeoenvironments | Year: 2014

The rich and diverse fossil mammalian assemblage from Gratkorn (Middle Miocene, Austria) is of primary importance for the understanding of the faunal evolution in Central Europe. Besides large mammals, the fauna comprises: Schizogalerix voesendorfensis, Galericinae gen. et sp. indet., Desmanodon fluegeli, Dinosorex sp., cf. Myotis sp., "Cricetodon" fandli, Megacricetodon minutus, Eumyarion sp., Spermophilinus bredai, Blackia sp., Forsythia gaudryi, Albanensia albanensis, Muscardinus aff. Sansaniensis, Miodyromys sp., Keramidomys sp., Euroxenomys minutus minutus, Prolagus oeningensis, cf. Eurolagus fontannesi and Ochotonidae indet. Based on the degree of corrosion on the dental elements and the presence of pellets, most, but not all, of the material is tentatively interpreted as a result of accumulation by nocturnal raptors. In addition to the information provided by the lower vertebrates and the molluscs, which occur in abundance in the same thin fossil-enriched layer, the mammal fauna gives a mixed picture of the environment (basically forested vs. open landscape). This could indicate the presence of different microhabitats around the excavation place, but may also be a taphonomical artefact based on various different agents of accumulation contributing to the thanatocoenosis. Nevertheless, the extreme quick accumulation of the fossils provides an exceptional windows in the late Sarmatian s. Str. ecosystems. © 2014 Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg.

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