| Psilochasmus Lühe, 1909 |
| Psilochasmus oxyurus (Creplin, 1825) Lühe, 1909 |
| Psilostomidae Looss, 1900 |
| Psilostominae Looss, 1900 |
| Psilostomum Looss, 1899 |
| Psilostomum ondatrae Price, 1931 |
| Ribeiroia Travassos, 1939 |
| Ribeiroia insignis Travassos, 1939 |
| Ribeiroia ondatrae (Price, 1931) Price, 1942 |
| Ribeiroiinae Travassos, 1951 |