There are five valid, extant species of Verrallia and three extinct species. Kehlmaier (2006) worked on some of the nomenclatural problems with the group but did not provide keys as a complete revision is really needed. Kuznetzov (1992), Coe (1966) and Dunk (1997) provide keys, none of which are completely satisfactory. Current work on the genus is being conducted by Kehlmaier (European) and Skevington (Nearctic).