| Synonymous name | : | †Hyrachyus hypostylus Wood, 1934 | |
Ref: PBDB: 27 Oct 2013. |
| Synonymous name | : | †Hyrachyus imperialis Osborn et al., 1878 | |
Ref: PBDB: 26 Jul 2015. |
| Synonymous name | : | †Hyrachyus princeps Marsh, 1872 | |
Ref: PBDB: 12 May 2016. |
| Synonymous name | : | †Metahyrachyus troxelli Wood, 1934 | |
Ref: PBDB: 27 Oct 2013. |