Suborder Leptonidina Dall 1889 (clam)
Parent taxon: Cardiida according to J. G. Carter et al. 2011
Sister taxa: Anthracosiidina, Cardiidina, Gastrochaenidina, Kalenteroidea
Subtaxa: Cyamioidea Galeommatoidea
Ecology: facultatively mobile infaunal suspension feeder