Family Trigoniidae Lamarck 1819 (clam)
Parent taxon: Trigonioidea according to J. G. Carter et al. 2011
Sister taxa: Costatoriidae, Eoschizodidae, Groeberellidae, Myophoriidae, Prosogyrotrigoniidae, Scaphellinidae, Schizodidae
Subtaxa: Geratrigonia, Ibotrigonia, Kyushutrigonia, Latitrigonia, Linotrigonia, Lyroschizodus, Maputrigonia, Microtrigonia, Minetrigonia, Minetrigoniinae, Modesticoncha, Neotrigonia, Neuquenitrigoniinae, Nipponitrigonia, Nototrigoniinae, Pleurotrigoniinae, Psilotrigoniinae, Quadratotrigonia, Rutitrigonia, Scaphotrigonia, Steinmanella, Trigoniinae, Turbitrigonia
Ecology: facultatively mobile infaunal suspension feeder