Cardinal process is a structure on dorsal valve of brachiopods serving for separation or attachment of diductor muscles. A cardinal process with a peculiar folded myophore is described from Late Ordovician “Orthis” kukersiana−group brachiopods assigned to the genus Cyrtonotella (order Orthida). This structure differs from those of other rhynchonelliformean brachiopods and can be considered as a separate type among about twenty varieties of processes described up to now.

Linda Hints [Linda.Hints@gi.ee], Institute of Geology at Tallinn University of Technology, 7 Estonia Boulevard, 10143 Tallinn, Estonia.