First report of the mitrate Mitrocystella (Echinodermata, Stylophora) in the Middle Ordovician of the Crozon Peninsula, Brittany (France)

The mid-Ordovician mitrocystitid mitrate Mitrocystella incipiens was one of the most widespread stylophorans in the high latitude Mediterranean Province, with occurrences in the Armorican Massif (France), the Iberian Peninsula (Portugal and Spain) and the Prague Basin (Czech Republic), all restricted so far to the late Darriwilian (Hustedograptus teretiusculus Zone). The description of this taxon in the Corréjou Member (Postolonnec Formation) of the Crozon Peninsula (western Brittany, France) not only extends its spatial distribution within the Armorican Massif, but also its stratigraphic range into the mid-Darriwilian (Didymograptus artus Zone). The remarkable preser vation of the new material and associated sedimentological evidence both suggest rapid burial by storm deposits.