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December 2016
Vol.40-2
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Print ISSN: 0031-0247
Online ISSN: 2274-0333
Frequency: biannual

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Additions to the elasmobranch fauna from the upper Cretaceous of New Jersey (middle Maastrichtian, Navesink Formation)
Gerard R. Case and Henri Cappetta
Keywords: Elasmobranchs; New Jersey; new species; Upper Cretaceous; USA
 
  Abstract

    A recently discovered, almost complete specimen of a hybodont tooth, allows us to describe as a new species, fairly common, but usually fragmentary teeth in the Navesink Formation of New Jersey: Hybodus novojerseyensis nov. sp.
    Three additional taxa are also described : Heterodontus creamridgensis, Squalicorax sp. and Pseudocorax affinis which is noted for the first time in North America.
    The whole elasmobranch fauna of the Early Maastrichtian localities of New Jersey is reevaluated and several generic assignments are changed in comparison to the list previously published in 1975 (Cappetta
    & Case). 


  Article infos

Published in Vol. 33, Fasc. 1-4 (2004)

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Experimental taphonomy inavian eggs and eggshells: effects on early diagenesis.
Ana M. Bravo, D. A. Buscalioni, Lauro Merino and B. G. Müller
Keywords: archosaurian eggshells; avian egg; Experimental taphonomy; geochemical analysis; pyritisation; Upper Cretaceous
 
  Abstract

    We experimentally explore the early taphonomic stages involving the decay and biodegradation of buried eggs and eggshells. Unfertilised commercial chicken eggs and eggshell fragments were buried in plastic containers and were kept under controlled conditions for eight months. Half of the containers were filled with marl, and the remainder with sand. All were saturated with fresh tap water, acidified water, sulphate water, or seawater. They were kept in the dark at 23.4-26 °C, except one, which was kept in a heating chamber at 37.4°C. We expected that different burial conditions would produce distinct taphonomic outcomes. Instead, the taphonomic alterations of buried eggs parallel that of the alteration of egg proteins (i.e., denaturation and/or putrefaction) with an additional role played by the eggshell. Mummification, encrustation, distortion and fragmentation, and necrokynesis (vertical displacement) depend on organic matter decay. The experiment identifies environmental conditions that may favour or actively promote these taphonomic processes. Of these, early pyritization is one of the most relevant. For comparative purposes, samples of fossil and extinct eggshell representing three distinct environmental burial conditions were examined. These included Megaloolithus, Caiman crocodilus, and Struthio camelus ootypes. The geochemical analysis of these eggshells showed no significant differences among the chemical variables of these fossil and extant ootypes. Eggshells exhibited a stable composition over a range of experimental conditions. 
      


  Article infos

Published in Vol. 32, Fasc. 2-4 (2003)

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Long-term fidelity of megaoolithid dinosaurs to a large breeding-ground in the Upper Cretaceous of Aix-en-Provence (southern France).
Géraldine Garcia, Yves Dutour, Isabellle Cojan, Xavier Valentin and Gilles Cheylan
Keywords: Large nesting ground; megaloolithid eggs; Southern France; Upper Cretaceous
 
  Abstract

    We present here the preliminary results from a new nesting site "Sextius-Mirabeau", discovered close to the historical centre of Aix-en-Provence in Upper Cretaceous deposits. This extensive megaloolithid nesting ground, the first large scale excavation (3225 m²) in France, yielded more than 530 eggs, some organized in clusters. Their study reveals the reproductive strategy of the megaloolithid egglayer group which indicates nesting fidelity and gregarious behaviour.  


  Article infos

Published in Vol. 32, Fasc. 2-4 (2003)

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