Taxonomic review of early Darriwilian estonioceratids (Tarphycerida, Nautiloidea) from Sweden, Estonia, and the ‘Diluvium-Geschiebe’ ofnorthern Germany and Poland

Estonioceratid nautiloids are a common and attractive component of mid-Ordovician (early Darriwilian) cephalopodfaunas in Baltoscandia. Their distinctive conchs are typically loosely coiled, and vary from forms which possess an apically coiledportion with divergent final whorl, to open gyrocones and even torticones. This paper briefly reviews the taxonomy of several mainly Swedish and Estonian estonioceratid genera which were formerly poorly known at the time of the publication of theTarphycerida section of the ‘Nautiloid Treatise Part K’ (FURNISH& GLENISTER1964) or have been described since.