LATEST DISCOVERIES ABOUT DECAPOD CRUSTACEANS FROM JURASSIC AND CRETACEOUS KONSERVAT-LAGERSTÄTTEN (Invited Presentation)

For the past 10 years, the study of exceptionally preserved crustaceans from Jurassic and Cretaceous Konservat-Lagerstätten has provided many discoveries in terms of systematics (increase of paleobiodiversity), palaeobiology (reproduction, sexual dimorphism), palaeoecology (morphological adaptations, modes of life), palaeoenvironment (bathymetry, pathway of colonization) and evolutionary history (phylogeny). Progress has come in particular from the use of X-ray microtomography as non-invasive tool to explore internal and external anatomy of specimens three-dimensionnaly preserved in concretions or nodules, but also from the systematization of observations under UV light of specimens preserved more or less flattened at the surface of lithographic limestones.

Here will be presented results on crustaceans from the Middle Jurassic (Callovian) La Voulte-sur-Rhône Lagerstätte, France (general anatomy, reproductive, digestive, respiratory and cardiovascular systems), from the Late Jurassic lithographic limestones of Europe (e.g., Solnhofen and neighbouring outcrops, Canjuers, Cerin), and from the Late Cretaceous of Lebanon (Cenomanian of Hakel, Hadjoula & Santonian of Sahel Alma) with new taxa and focus on fossilized eyes and adaptation of vision to depth.

Deposits of “intermediate” nature also exist and provide fossil crustaceans relatively well preserved in volume within siliceous or carbonate concretions, without reaching a Lagerstätten-type preservation. These intermediate deposits still provide high-quality anatomical details as well as new palaeobiological information on sexual dimorphism, paleosymbiosis and phenomena of moulting and autotomy. This is the case for the crustaceans found in some assemblages in the Jurassic of France (Callovian of Normandy & Oxfordian of Haute-Saône) and in the Early Cretaceous of the United Kingdom (Albian-Aptian, Isle of Wight).