| Quadraceps ravus (Kellogg, 1899) |
| Quadraceps semifissus (Nitzsch, 1866) |
| Quadraceps strepsilaris (Denny, 1842) |
| Rallicola Johnston & Harrison, 1911 |
| Rallicola (Rallicola) Johnston & Harrison, 1911 |
| Rallicola (Rallicola) colombiana (Carriker, 1906) |
| Rallicola (Rallicola) deckeri Adams, 2001 |
| Rallicola (Rallicola) exiguifrons (Carriker, 1944) |
| Rallicola (Rallicola) fuliginosa (Carriker, 1963) |
| Rallicola (Rallicola) parvigenitalis (Carriker, 1944) |
| Rhopaloceras Taschenberg, 1882 |
| Rhopaloceras heterogenitalis Carriker, 1944 |
| Rhopaloceras rudimentarius Carriker, 1936 |
| Rotundiceps Edwards, 1952 |
| Rotundiceps cordatus (Osborn, 1896) |
| Saemundssonia Timmermann, 1936 |
| Saemundssonia brevicornis Giebel, 1874 |
| Saemundssonia haematopi (Linnaeus, 1758) |
| Saemundssonia insolita (Kellogg, 1896) |
| Saemundssonia lari (O. Fabricius, 1780) |