Standard nomenclature and metrics of plane shapes for use in Gregarine taxonomy

Current practice in gregarine (Apicomplexa: Eugregarinorida) taxonomy does not include a standard nomenclature and metric set for plane shapes even though most taxonomic works within the group depend on shape-based descriptions. The lack of a uniform shape nomenclature and metric set has produced considerable confusion in gregarine systematics: descriptions of species often are not directly comparable even among congeneric taxa. As a step toward unifying taxonomic practice within Eugregarinorida. a standard nomenclature and metric set for 278 plane shapes in 23 shape series is delineated.