Search results for "Universe"

Découverte d’un nouveau site à traces de pas de Dinosaures dans le Bathonien des Causses (Le Gayrand, Gorges de la Jonte, Lozère, France).

2012

7 pages; National audience

Les faunes d'échinodermes.

2013

4 pages; National audience

Echinoderm evolution since 1972 and since the cambrian: tales from a dozen IECS.

2006

5 pages; International audience; Progress made since the first IEC - which took place in Washington, DC in 1972 has drastically altered some of our views on echinoderm evolution. In addition to publications in scientific journals, there are thousands of pages of peer-reviewed material in the proceedings of past IECs, and in Echinoderm Studies. These pages bear witness to some of the most outstanding milestones in this progress. This paper aims to highlight one third of a century of maturing ideas dealing with several key aspects of echinoderm evolution as witnessed by 12 IECs. Conceptual changes have taken place in a scientific milieu characterized by rapid adoption of new theoretical and p…

Pelagic ecosystem recovery after end-Permian mass extinction.

2011

4 pages

Reappraisal of ambulacral branching patterns in blastozoans

2006

6 pages; International audience; The type of ambulacral bifurcation is an important diagnostic character in primitive echinoderms. However this character is rarely used in blastozoan phylogenetic studies, whereas the corresponding character is well used in crinoid analyses. The main reason for this gap is the absence of definition of patterns for all blastozoans, resulting in terminological confusion. Although crinoid arms and blastozoan ambulacra are not homologous, the well-defined crinoid terminology has been used to describe the different topologies of ambulacral bifurcation. Unilateral and bilateral patterns have been recognized in blastozoans, and associated with the mineralization of…

Smithian (Early Triassic) ammonoids from Crittenden Springs, Elko County, Nevada: taxonomy, biostratigraphy and biogeography.

2018

175 pages; International audience; We present a comprehensive monographic treatment of all currently known Smithian (Early Triassic) ammonoidtaxa from Crittenden Springs. Extensive collection efforts from numerous stratigraphically discontinuous, condensedoutcrops over a period spanning four decades has yielded a total of 60 taxa. This activity has also resulted in the recognitionof a new biostratigraphic succession unique to Crittenden Springs, consisting of 12 ammonoid intervals that normallyoccur within a typical ~1 m thick condensed outcrop. Ammonoids of early Smithian age are reported for the first timefrom this locality. Intraspecific variation of the more abundant taxa is documented …

First Kimmeridgian/Tithonian flora from thelithographic limestone of the Causse Méjean(Lozère, southern France)

2016

National audience; Fossiliferous lithographic limestone yielding Kimmeridgian/Tithonian floras has been reported from few localities, mainlylocated in western Europe (e.g., Plattenkalk of Bavaria in Germany,or Canjuers and Cerin in France). They were studied intensivelyduring the twentieth century, when the fossil plants weremainly ascribed to bennettitaleans, conifers, cycads, ginkgophytesand pteridosperms. Here, we report the first flora from the Kimmeridgian/Tithonian lithographic limestone in the northern partof the Causses Basin. These fossils were discovered in the depositsof a small quarry in the Causse Méjean, which is no longeraccessible, as it has been completely filled in. The se…

A revision of the rare genus Cyclolampas (Echinoidea) using morphometrics with description of a new species from the upper Callovian of Burgundy (Fra…

2013

18 pages; International audience; The discovery of a new species, Cyclolampas altus new species in the upper Callovian of Burgundy (France) leads to the systematic revision of the rare echinoid genus Cyclolampas Pomel, 1883. Two morphometric approaches are used jointly to describe and quantify variations in test shape: the analysis of linear measurements and the Elliptic Fourier shape analysis. Both analyses yield congruent results that highlight the amplitude of within-species variations and quantify the part due to allometry. Along with the description of C. altus, the systematic position of species formerly assigned to the genera Pygorhytis Pomel, 1883 and Cyclolampas is amended. Previou…

Pierre Rat (1921-2010).

2012

Le remplissage plio-pleistocène du fossé bressan dans la région de Bourg en Bresse

1988

Le remplissage plio-pléistocène du Fossé bressan dans la region de Bourg-en-Bresse commence par le Complexe des Marnes de Bresse , d ' âge pliocène, correspondant à des dépôts fins caractéristiques d'une basse plaine marécageuse . Il se poursuit par des épanchements de cailloutis à caractères fluviatiles qui ont pu être regroupés par des arguments cartographiques , géométriques et d ' âge , au sein du Complexe de couverture bressan pléistocène inférieur. Cet ensemble est recouvert par le Complexe des moraines externes , attribué au Riss "ancien", en avant duquel se développe un système fluvioglaciaire relayé par un système lacustre . Le Complexe de Saint-Cosme Riss " récent" apparaît emboît…