Article: Taxonomic criteria in the classification of the Pennsylvanian productoid Juresania nebrascensis

Biometrical and qualitative analysis of the form of the cardinal process in a sample of 123 brachial valves of Juresania nebrascensis (Owen) indicates that this feature is more variable than the size and shape of the valve proper. This relatively greater variability suggests that the form of the cardinal process has only limited value as a taxonomic criterion in the classification of this species.