Balanocrinus and other crinoids from Late Jurassic mudstones of France and Switzerland

Abstract

Late Jurassic mudstones of France and Switzerland are rich in remains of the isocrinid Balanocrinus. From the early Late Oxfordian of Savigna (Departement du Jura, France) Balanocrinus brachiospina is described as new; the material includes all growth stages and skeletal elements, allowing the reconstruction of the animal and description of ontogenetic changes. The remains of Balanocrinus from Savigna are compared with Balanocrinus subteres (Munster in Goldfuss) from the Middle Oxfordian sponge facies of Holderbank (northern Switzerland) and with Balanocrinus pentagonalis (Goldfuss) from the Early Oxfordian of Les Rouges-Terres (Canton of Jura, Switzerland. The present material enables improved diagnoses of the two common Oxfordian species, B. subteres and B. pentagonalis. The Savigna locality includes two rare new comatulids, Palaeocomaster musculosus n. sp. and Andymetra donovani n. sp. The late Early Oxfordian locality of Andelot-Morval near Saint-Amour (Departement du Jura, France) furnished B. brachiospina n. sp., and the comatulids are represented by Palaeocomaster musculosus n. sp., Archaeometra scrobiculata (Goldfuss) and Semiometra petitclerci (Caillet). The paracomatulid Paracomatula morator n. sp. from Andelot is the last representative of the group. Numerous remains of the cyrtocrinid Tetracrinus galei n. sp. supplement the Andelot fauna.