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Dermal denticles of two thelodont agnathans, Australolepis seddoni gen. et sp. nov., and a possible nikoliviid gen. et sp. indet. are described from the Gneudna Formation, a marine sequence of interbedded limestone and shale exposed on the eastern edge of the Carnarvon Basin, Western Australia. The age and significance of these new forms are discussed. The Gneudna Formation is Late Devonian, probably early Frasnian, which, if confirmed, makes these the youngest thelodonts known to date.  相似文献   
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Benson, R.B.J., Fitzgerald, E.M.G., Rich, T.H. & Vickers-Rich, P., 2013. Large freshwater plesiosaurian from the Cretaceous (Aptian) of Australia. Alcheringa 37, 1–6. ISSN 0311-5518

We report a large plesiosaurian tooth from the freshwater early–middle Aptian (Early Cretaceous) Eumeralla Formation of Victoria, Australia. This, combined with records of smaller plesiosaurian teeth with an alternative morphology, provides evidence for a multitaxic freshwater plesiosaurian assemblage. Dental and body size differences suggest ecological partitioning of sympatric freshwater plesiosaurians analogous to that in modern freshwater odontocete cetaceans. The evolutionarily plastic body plan of Plesiosauria may have facilitated niche differentiation and helped them to exclude ichthyosaurs from freshwater environments during the Mesozoic. However, confirmation of this hypothesis requires the discovery of more complete remains.

Roger B.J. Benson [roger.benson@earth.ox.ac.uk], Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK; Erich M.G. Fitzgerald [efitzgerald@museum.vic.gov.au], Thomas H. Rich [trich@museum.vic.gov.au], Museum Victoria, GPO Box 666, Melbourne, Victoria 3001, Australia; Thomas H. Rich and Patricia Vickers-Rich [pat.rich@monash.edu], School of Geosciences, Monash University, Clayton, Victoria 3800, Australia. Received 30.10.2012; revised 27.1.2013; accepted 31.1.2013.  相似文献   
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The word ‘stromatolite’ should only be applied to organosedimentary structures predominantly accreted by sediment trapping, binding and/or in situ precipitation as a result of the growth and metabolic activities of benthic, principally prokaryotic, micro-organisms. Structures of uncertain origin that resemble stromatolites should be called ‘stromatoloids’. This cautious approach would eliminate the currently common assumption that structures with mesoscopic morphological similarities to microbially accreted sedimentary structures must be biogenic, a misconception that hampers investigations into the antiquity of life.

A hierarchical series of meso- and microstructural attributes of stromatolites can be used to assign gradually increasing probabilities of biogenicity to stromatoloids. This method is particularly useful for interpreting ancient noncolumnar stromatoloids with poor microstructural preservation. In a range of Early Archaean pseudocolumnar, nodular and stratiform stromatoloids from North Pole studied using this method, none could be proved to be stromatolites and only a few are probable or possible stromatolites. As these stromatoloids closely resemble previously reported structures from North Pole interpreted as stromatolites, we consider that the evidence for the existence of life c. 3500 my ago at North Pole is less definitive than previously supposed.  相似文献   
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The dramatic growth of drone warfare in the last decade has meant the arrival of a new kind of war imagery in civilian life: the view through the drone camera. As such, the drone is not simply a weapon, but also an emerging medium for representing conflict. This article explores the ways this imagery has been selected, interpreted, framed and put to use in public and popular culture. In addition to exploring how these practices of looking fit within the larger history of war imagery, two prominent features of ‘drone vision’ are identified: the promotion of consumer interactivity in the drone war and the militarising of domestic space.  相似文献   
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Abstract

The little-known ‘great escape’ of Allied prisoners-of-war (some 50,000) held in Italian camps at the time of the armistice of 8 September 1943 provides the starting-point for a fresh interpretation of popular and peasant experience during the emergency of 1943 – 5. The article explores some of the main aspects of the ‘strange alliance’ between Allied fugitives and the Italian population, with particular attention to the mutual symbolic appropriation between former ‘enemies’ in the midst of a civil war and related collapse of the state.  相似文献   
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