Extinct species within this genus include: • †
Isognomon gariesensis Kensley and Pether 1986 • †
Isognomon gaudichaudi d'Orbigny 1842 • †
Isognomon isognomoides Stahl 1824 • †
Isognomon isognomon Linnaeus 1758 • †
Isognomon isognomonoides Stahl 1824 • †
Isognomon legumen Gmelin 1790 • †
Isognomon maxillatus Lamarck 1819 • †
Isognomon nucleus Lamarck 1819 • †
Isognomon quadrisulcata Ihering 1897 • †
Isognomon valvanoi Rossi de Garcia and Levy 1977 • †
Isognomon wellmani Crampton, 1988 ;Species brought into synonymy: •
Isognomon acutirostris (Dunker, 1869): synonym of
Isognomon nucleus (Lamarck, 1819) •
Isognomon anomioides (Reeve, 1858): synonym of
Isognomon australica (Reeve, 1858) •
Isognomon aviculare (Lamarck, 1819): synonym of
Isognomon isognomum (Linnaeus, 1758) •
Isognomon brevirostre Link, 1807: synonym of
Isognomon isognomum (Linnaeus, 1758) •
Isognomon dentifer (Krauss, 1848): synonym of
Isognomon nucleus (Lamarck, 1819) •
Isognomon isognomon (Linnaeus, 1758): synonym of
Isognomon isognomum (Linnaeus, 1758) •
Isognomon roberti Koch, 1953: synonym of
Isognomon perna (Linnaeus, 1767) •
Isognomon rude (Reeve, 1858): synonym of
Isognomon isognomum (Linnaeus, 1758) •
Isognomon rupella (Dufo, 1840): synonym of
Isognomon nucleus (Lamarck, 1819) •
Isognomon sulcatum Lamarck: synonym of
Isognomon perna (Linnaeus, 1767) •
Isognomon vulsella (Lamarck, 1819): synonym of
Isognomon legumen (Gmelin, 1791) ==References==