Search results for "CEO"

Micro- to macro-scale internal structures, diagenesis and petrophysical evolution of injectite networks in the Vocontian Basin (France): implications…

2015

27 pages; International audience; This study discusses the characteristics of two Lower Cretaceous injectite networks in the Vocontian Basin (SE France) using combined structural, sedimentary, diagenetic, and petrophysical analyses. Internal structures, at both the macro- and micro-scale, and diagenetic phases characterising these injectite networks have been described. Simultaneously, precementation porosity values were estimated and parameters controlling the geographical distributions of these values were analysed and statistically tested. All of the data were integrated so as to reconstruct the spatial evolution of the porosity from the time of injection to modern times through five maj…

Support for a Vraconnian Stage between the Albian sensu stricto and the Cenomanian (Cretaceous System)

2008

The geological scale for the middle Cretaceous currently used throughout the world was proposed by Alcide d'Orbigny in the XIXth century between the years 1842 and 1847 and establishes the succession of stages as Albian, Cenomanian and Turonian. In 1868 Renevier proposed that a supplemental chronostratigraphic division be intercalated between the Albian and the Cenomanian: the Vraconnian stage. This term was not generally accepted and after a period when it was referred to by Breistroffer (1936) as a substage constituting the upper part of the Albian, as an equivalent of the Stoliczkaia dispar ammonite Zone, its abandonment was "recommended" by the Conference on the Lower Cretaceous held in…

Il turismo come strumento di sviluppo urbano sostenibile: un caso studio

2009

Description of two new fossil echinoids (Echinodermata: Echinoidea) from the Early Hauterivian (Early Cretaceous) of the Paris Basin (France)

2012

International audience; Deux nouveaux genres et espèces d'échinides, Salvaster roberti gen. et sp. nov. et Pygolampas edita gen. et sp. nov. provenant de la Formation des Calcaires à Spatangues (CSF) sont décrits. La CSF correspond à des sédiments calcaréo-argileux déposés dans le sud-est du bassin de Paris (France) à l'Hauterivien inférieur (Crétacé inférieur). Ces dépôts sont datés de la chronozone à Acanthodiscus radiatus, un intervalle de temps qui a correspondu à un haut niveau marin général en Europe de l'Ouest. La CSF a pourtant livré une riche faune fossile d'environnement marin peu profond, principalement représentée par des invertébrés benthiques. Parmi ceux-ci, 54 espèces d'échin…

First record ofColoborhynchus (Pterosauria) from the Santana Formation (Lower Cretaceous) of the Chapada do Araripe, Brazil

2001

The anterior tips of associated upper and lower jaws of a pterosaur from the Lower Cretaceous of Brazil are described and assigned to the taxonColoborhynchus in the family Ornithocheiridae. It is characterized by the shape and position of the sagittal crest on the upper and lower jaw, the arrangement and length of the teeth and the spoon-like lateral expansion of the anterior parts of the jaws. It closely resemblesColoborhynchus wadleighi from North America andColoborhynchus clavirostris from England. Diagnostic anatomical characteristics permit a revision of the genusTropeognathus, which is shown here to be a junior synonym of other described taxa.Tropeognathus mesembrinus is referred toCr…

Micromorphological approach to the systematics of Mediterranean Isoëtes species (Isoëtaceae, Lycopodiophyta): analysis of the megaspore surface

2012

Megaspore ornamentation is one of the few morphological characters used in the taxonomy of the genus Isoëtes. In the present work, we test the application of this character for distinguishing some Isoëtes species occurring in the Mediterranean: Isoëtes sicula, which according to some authors should be included as a variety in I. histrix, and the recently described I. todaroana, whose affinity with other taxa is currently unknown. Two additional species (I. duriei, I. velata) were also included in the analysis. The megaspores were studied using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy and chemical treatment. In all species, the megaspore surface is cove…

HNRNPR Variants that Impair Homeobox Gene Expression Drive Developmental Disorders in Humans

2019

The heterogeneous nuclear ribonucleoprotein (HNRNP) genes code for a set of RNA-binding proteins that function primarily in the spliceosome C complex. Pathogenic variants in these genes can drive neurodegeneration, through a mechanism involving excessive stress-granule formation, or developmental defects, through mechanisms that are not known. Here, we report four unrelated individuals who have truncating or missense variants in the same C-terminal region of hnRNPR and who have multisystem developmental defects including abnormalities of the brain and skeleton, dysmorphic facies, brachydactyly, seizures, and hypoplastic external genitalia. We further identified in the literature a fifth ind…

Dinosaur bonebed amber from an original swamp forest soil

2021

AbstractDinosaur bonebeds with amber content, yet scarce, offer a superior wealth and quality of data on ancient terrestrial ecosystems. However, the preserved palaeodiversity and/or taphonomic characteristics of these exceptional localities had hitherto limited their palaeobiological potential. Here we describe the amber from the Lower Cretaceous dinosaur bonebed of Ariño (Teruel, Spain) using a multidisciplinary approach. Amber is found in both a root layer with amber strictly in situ and a litter layer namely composed of aerial pieces unusually rich in bioinclusions, encompassing 11 insect orders, arachnids, and a few plant and vertebrate remains, including a feather. Additional palaeont…

Latest Cretaceous storm-generated sea grass accumulations in the Maastrichtian type area, the Netherlands – preliminary observations

2019

Abstract Ever since the first description of fossil material during the mid-nineteenth century, sea grass has been shown to be quite commonly preserved in ‘pockets’ or ‘clumps’ at certain levels within the Gulpen, Maastricht and Kunrade formations in southern Limburg (the Netherlands) and contiguous areas in northeast Belgium. In those places where silicification occurred during early diagenesis, even completely silicified and three-dimensionally preserved stems and roots can be found, mostly of Thalassocharis bosquetii, in association with fully marine molluscs such as dentaliid scaphopods and a range of larger foraminifera, bivalves, gastropods and ammonites. Such occurrences are best kno…

The complex nature of progenetic species — examples from Mesozoic ammonites

1991

Several examples of progenetic species among Mesozoic ammonites are investigated. The ammonites are Middle Jurassic kosmoceratids, Upper Jurassic oppeliids, and Upper Cretaceous scaphites. As assessed through outgroup comparison, the progenetic species in each of these examples is characterized by small size at maturity and the presence of morphological features typical of those of the juveniles of more primitive species. However, in none of these examples is the progenetic species a duplicate form of the juvenile stage of more primitive species. There are at least three kinds of features of progenetic species that differ from those of the juveniles of more primitive species: (1) symplesiom…