Alternative spelling: Galeommatacea
Parent taxon: Leptonidina according to J. G. Carter et al. 2011
See also Beu et al. 1990, Bieler and Mikkelsen 2006, Bouchet et al. 2010, Coan et al. 2000, Nevesskaja 2009, Rosenberg 2005 and Vokes 1980
Sister taxon: Cyamioidea
Subtaxa: Ephippiodontidae Galeommatidae Lasaeidae
Ecology: stationary infaunal suspension feeder
Distribution:
• Quaternary of Argentina (3 collections), Australia (1), Ecuador (3), France (2), Japan (2), Mexico (10), Morocco (1), the Netherlands (5), Poland (2), Türkiye (2), the United Kingdom (10), United States (45: Alaska, California, Louisiana, Maryland, Massachusetts, New Jersey, North Carolina, South Carolina)
• Pliocene of Australia (1), Belgium (6), Greece (1), Indonesia (1), Jamaica (1), Panama (1), the United Kingdom (4), United States (8: California, North Carolina, South Carolina, Virginia)
• Miocene of Australia (2), Belgium (11), Bulgaria (1), Denmark (1), Ecuador (1), France (2), Germany (10), Italy (2), the Netherlands (2), Panama (3), Poland (1), United States (22: Florida, Maryland, Nebraska)
• Oligocene of France (1), Germany (1), United States (2: Washington)
• Eocene of France (1), New Zealand (2), the United Kingdom (1), United States (10: Alabama, California, Mississippi, Oregon, Texas)
• Paleocene of Belgium (1)
• Cretaceous of United States (4: South Dakota, Texas)
Total: 190 collections including 262 occurrences