A Lower Silurian (Aeronian) radiolarian assemblage from black cherts of the Armorican Massif (France)

International audienceThe Chalonnes-sur-Loire outcrop is the most complete Llandovery section in the Ligerian domain (Armorican Massif, NW France); it displays a ca. 10 m-thick sequence of organic-rich black bedded cherts alternating with black graptolitic shales, which were deposited above glaciomarine diamictites of the Hirnantian glaciation. It is likely the black cherts accumulated under eutrophic waters, on the outer shelf part (distal offshore) of a Gondwanan margin, situated at intermediate to high latitudes of the Southern hemisphere. Hydrofluoric acid processing allowed the extraction of radiolarians; seven species are identified in the best preserved sample discovered so far. All seven are common species in tropical assemblages known from Alaska and Nevada, which are characteristic of the Orbiculopylorum assemblage, of Aeronian to early Telychian age. This age is in good agreement with independent age control from graptolites in the Chalonnes section, suggestive of an Aeronian age for the radiolarian-yielding level

Paleontology in France: 200 years in the footsteps of Cuvier and Lamarck

International audienceDue to its richness in fossil localities and Fossil-Lagerstätten, France played a major role in the 18th and 19th centuries in establishing paleontology and biostratigraphy as scientific disciplines. The French naturalist and zoologist Cuvier (1769-1832) established the fields of comparative anatomy and paleontology, and proposed the concept of 'catastrophism' in geology. The naturalist Lamarck (1744-1829) is considered the founder of invertebrate paleontology and biostratigraphy and an early pioneer in the studies of evolution, developing the idea of 'transformism' and creating the word 'fossil', while his successor Blainville (1777-1850) was the first to use the word 'paleontology'. Based on this rich heritage, numerous French scientists strengthened paleontology as an important discipline during the 19th and 20th centuries. Paleontology was present at the universities of most major French cities, as documented by the rich collections in over 50 natural history museums and university collections. The most significant paleontological collection is that housed in the Muséum National d'Histoire Naturelle (MNHN) at Paris that currently hosts the largest research unit in paleontology of France with over 100 scientists, curators and technicians. The second largest collection (and the largest in terms of invertebrate fossils) is housed at the University of Lyon1, where the most important university paleontology research team is present. About 250 professional paleontologists are currently working in research units that are mostly affiliated to the Centre National de Recherche Scientifique (CNRS), in public or private museums, or in the numerous natural parcs. A significant generation change took place in the early 2000s, with the retirement of the paleontologists recruited in the 1960s and 1970s, that were often specialized in alpha-taxonomy and stratigraphy, and the arrival of a young generation of scientists that attempts to answer more 'modern' questions, such as global (climate) change, biodiversity, or evolution. This new generation of paleontologists faces modified funding schemes with project-based supporting structures in a more and more competitive environment. In the present paper we attempt to summarize the current situation of paleontology as a discipline in the very complex academic and scientific context of France. After a short overview on the history of French paleontology in the last centuries, a synopsis on institutions and funding agencies is presented briefly. The major research departments and their research themes are then described, together with the most important collections, the paleontological associations, journals, and databases, etc. Paleontological training possibilities and job opportunities, in particular in academia, are next documented, concluding with a summary of the prospects of the discipline

FRASNIAN (UPPER DEVONIAN) BRACHIOPODS FROM ARMENIA: BIOSTRATIGRAPHIC AND PALAEOBIOGEOGRAPHIC IMPLICATIONS

An assemblage of seven brachiopod species belonging to the orders Rhynchonellida, Atrypida and Spiriferida are studied from three localities (Ertych, Djravank and Noravank) of Central Armenia. The examined material is recovered from shallow water nodular limestones and provides insights into the diversity of Frasnian brachiopods on that part of the northern margin of Gondwana preserved within the South Armenian Block. The revision of Atrypa (Planatrypa) ertichensis, a biostratigraphically significant species for the Frasnian of the Lesser Caucasus (Armenia and Nakhichevan), revealed the presence of frills, an ornamental feature rarely observed in Atrypa (Planatrypa) representatives and considered as unknown in this species. Taxonomic discussion also involves the selection of neotypes for Ripidiorhynchus gnishikensis and A. (P.) ertichensis. The newly described taxon, Angustisulcispirifer arakelyani n. gen., n. sp., appears to be one of the most biostratigraphically important species for the Frasnian of Armenia. The size variability of Cyphoterorhynchus koraghensis and Desquamatia (Seratrypa) abramianae is documented quantitatively for the first time and it shows a continuous and progressive growth without any distinct groupings; the former is a palaeobiogeographically important species for the Frasnian strata of the northern Gondwana margin. Pending the revision of the Pakistani and Iranian material ascribed to C. koraghensis, that may include several subspecies, a plaster cast of its lectotype from the Frasnian of Kuragh in Chitral (northwest Pakistan) and the holotype as well as one of the paratypes of Cyphoterorhynchus koraghensis interpositus from the Frasnian Bahram Formation of the Ozbak-Kuh region in eastern Iran are illustrated herein. Finally, a new Frasnian brachiopod zone, namely the Ripidiorhynchus gnishikensis–Angustisulcispirifer arakelyani assemblage Zone is here introduced for the studied sections. Although its base and top cannot be identified, it is constrained to the Frasnian based on conodonts identified in the Djravank section. It may be considered as a partly lateral equivalent of the Cyrtospirifer subarchiaci–Cyphoterorhynchus arpaensis brachiopod Zone established in Nakhichevan

Scheduling in Dense Small Cells with Successive Interference Cancellation

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Taxonomic study of Ordovician (Llanvirn-Caradoc) Radiolaria from the Southern Uplands (Scotland, U.K.)

Volume: 21Start Page: 625End Page: 63