Alternative spelling: Cyamiacea
Parent taxon: Leptonidina according to J. G. Carter et al. 2011
See also Bieler and Mikkelsen 2006, Bouchet et al. 2010, Coan et al. 2000, Nevesskaja 2009, Newell 1965, Rosenberg 2005, Vokes 1980 and Ward and Blackwelder 1987
Sister taxon: Galeommatoidea
Subtaxa: Basterotiidae Cyamiidae Galatheavalvidae Neoleptonidae Perrierinidae Sportellidae
Ecology: facultatively mobile infaunal suspension feeder
Distribution:
• Quaternary of Argentina (4 collections), Ecuador (1), Japan (4), New Zealand (1), United States (31: California, Florida, North Carolina, South Carolina)
• Pliocene to Pleistocene of United States (1: California)
• Pliocene of Antarctica (1), Australia (1), Jamaica (1), the United Kingdom (1), United States (6: Florida, North Carolina, Virginia), Venezuela (1)
• Miocene of Australia (2), Austria (1), Colombia (2), France (1), Germany (1), the Netherlands (2), New Zealand (3), United States (27: Florida, New Jersey)
• Oligocene of United States (10: Mississippi)
• Eocene of Antarctica (3), Saudi Arabia (1), the United Kingdom (3), United States (7: Alabama, Texas)
• Paleocene of Belgium (1), United States (6: Alabama, Texas)
• Cretaceous of United States (2: South Dakota)
• Permian of Pakistan (1)
Total: 126 collections including 165 occurrences