The La Voulte-sur-Rhône Lagerstنtte (Middle Jurassic, France)

The La Voulte Lagerstنtte (Jurassic, France) is characterized by a diverse and exceptionally well-preserved fauna. It was located along the western Tethyan margin where the submarine relief was steep. The sedimentation was dominated by marls suggesting a low energy and deep-water depositional environment. The La Voulte biota is remarkable for its biodiversity with about 60 different species. The major components are the arthropods (50% of the species), the cephalopods (10%) and the echinoderms (10%). Among the arthropods, the composition and some anatomical features suggest a relatively deep-water environment characterized by dim-light conditions. The cephalopods and other organisms (pycnogonids, asterids), have extant analogues that all live in deep-water niches always exceeding 200 m. The fauna as a whole bears the characteristic features of the present-day bathyal fauna. The La Voulte Lagerstنtte may be one of the rare Jurassic Lagerstنtten, if not the unique, to have fossilized a deep marine fauna.