Sagmatias is a genus that has been proposed for certain dolphin species that are currently placed in the genus Lagenorhynchus. Mitochondrial DNA studies have indicated that certain dolphin species within Lagenorhynchus are actually more closely related to dolphins within the genus Cephalorhynchus. In order to resolve this situation it has been proposed that the affected dolphin species be placed within the genus Sagmatias. Affected species are:
- Pacific White-sided Dolphin (Lagenorhynchus obliquidens)
- Peale's Dolphin (Lagenorhynchus australis)
- Dusky Dolphin (Lagenorhynchus obscurus)
In addition, there is evidence that the Hourglass Dolphin (Lagenorhynchus cruciger) should also be placed within the new genus, although the evidence for this species is less conclusive.
Under this categorization, Sagmatias, Cephalorhynchus and Lissodelphis form the subfamily Lissodelphininae within the dolphin family, Delphinidae.