†superfamily Mecynodontoidea Haffer 1959 (clam)
Parent taxon: Megalodontida according to J. G. Carter et al. 2011
Sister taxon: Megalodontoidea
Subtaxa: Beichuaniidae Congeriomorphidae Mecynodontidae Plethocardiidae Prosocoelidae
Ecology: facultatively mobile infaunal suspension feeder
Distribution:
• Devonian of China (2 collections), Germany (1), United States (1: Arizona)
• Ordovician of Canada (1: Ontario), the Russian Federation (1), United States (19: Illinois, Iowa, Minnesota, Minnesota, Illinois, Iowa)
Total: 25 collections including 26 occurrences