|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||Age range and collections|
Echinoidea - Cassiduloida
It was reranked as Procassidulus (Hardouinia) by Lambert and Thiéry (1921); it was corrected as Harduinia by Smith (2001).
It was assigned to Procassidulus by Lambert and Thiéry (1921); to Faujasiidae by Kier (1966); and to Cassiduloida by Smith (2001) and Sepkoski (2002).
If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.