|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Bivalvia - Cardiida - Cardiidae
It was reranked as Protocardia (Pachycardium) by Schneider (1995); it was reranked as Cardium (Pachycardium) by Kosnik (2002).
It was assigned to Cardiidae by Popenoe (1937); to Protocardiinae by Vokes (1980); to Protocardia by Schneider (1995); to Veneroida by Sepkoski (2002); and to Cardium by Kosnik (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.