Bivalvia - Cardiida - Cardiidae
Alternative spelling: Pachycardium
Parent taxon: Protocardia according to J. A. Schneider 1995
See also Kosnik 2002, Popenoe 1937, Sepkoski 2002 and Vokes 1980
Sister taxa: Cardium (Protocardia) arkansense, Cardium (Protocardia) pauli, Cardium (Protocardium) granuliferum, Protocardia (Grypocardia), Protocardia (Leptocardia), Protocardia (Protocardia), Protocardia (Tamilicardia), Protocardia alcesiana, Protocardia buckmani, Protocardia costaricensis, Protocardia dufrenoyca, Protocardia eduliformis, Protocardia gambrina, Protocardia hillana, Protocardia intexta, Protocardia lingulata, Protocardia luggudensis, Protocardia newberryana, Protocardia peregrinorsa, Protocardia pesolina, Protocardia philippiana, Protocardia piettei, Protocardia placerensis, Protocardia pulchella, Protocardia qinghaiensis, Protocardia razavii, Protocardia rhaetica, Protocardia salrivalis, Protocardia somaliensis, Protocardia stantoni, Protocardia stonei, Protocardia striatula, Protocardia stricklandi, Protocardia subquadrata, Protocardia texanum, Protocardia translucida, Protocardia truncata, Protocardia umkwelanensis, Protocardia virginiana, Protocardium (Brevicardium)
Subtaxa: Pachycardium coronaensis Pachycardium remondianum
Ecology: facultatively mobile infaunal suspension feeder
Distribution:
• Cretaceous of Brazil (1 collection), India (1), Madagascar (1), United States (68: Alabama, Arkansas, California, Georgia, Maryland, Mississippi, Missouri, New Jersey, North Carolina, South Carolina, Texas)
Total: 71 collections including 73 occurrences