This order comprises the following families: 

• Heliornithidae (Sungrebe, Finfoots)
• Sarothruridae (Flufftails, Wood Rails)
• Rallidae (Rail)
• Gruidae (Cranes)
• Aramidae (Limpkin)
• Psophiidae (Trumpeters)

Genus-level timetree of extant Gruiformes according to Prum et al. (2015), Boast et al. (2019), Kuhl et al. (2021), and Kirchman et al. (2021), with the distribution of each taxon being indicated by the colour-code used throughout this website (see Distribution code).  According to the results of Kuhl et al. (2021) the divergence between the gruid genera Balearica and Bugeranus occurred at 13 Ma, whereas Krajewski et al. (2010) assumed this divergence to have occurred much earlier at 31-37 Ma. Accepting the divergence times given by Kuhl et al. (2021) and considering the fact that Krajewski et al. (2010) further assumed that the divergence between Leucogeranus and the remaining gruid genera occurred at 12-14 Ma, it follows that all gruid genera except Balearica should probably be placed in a single genus Grus. Neither Prum et al. (2015) nor Kuhl et al. (2021) treated any species of Sarothruridae, so  intrinsic divergence times have not been established yet. 

Genus-level timetree of extant Rallidae according to Boast et al. (2019), Garcia-R. et al. (2020), Garcia-R. & Matzke (2021), and Kirchman et al. (2021), with the distribution of each taxon being indicated by the colour-code used throughout this website (see Distribution code). 

Kirchman et al. (2021) provided a revised classification of the superfamily Ralloidea which is represented below. It should be noted, however, that the number of rallid tribes may be slightly exaggerated, with some of them being less than 10 Ma. 

References

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