| Synonymous name | : | †Aminippus (Genus) Granger, 1908 | |
Ref: PBDB: 16 May 2017. |
| Synonymous name | : | †Helohippus (Genus) Marsh, 1892 | |
Ref: PBDB: 4 Sep 2019. |
| Synonymous name | : | †Helotherium (Genus) Cope, 1872 | |
Ref: PBDB: 24 Oct 2014. |
| Synonymous name | : | †Oligotomus (Genus) Cope, 1873 | |
Ref: PBDB: 17 Oct 2017. |