1998, placed it in a subtribe Crecina of the crakes. Its exact position could not be determined, but it was suggested to perhaps be the sister taxon to the genus Laterallus, a genus of small crakes found mostly in South America. Two extinct flightless species of rail were at one time placed in the genus Atlantisia with the Inaccessible Island rail. The Ascension crake (Mundia elpenor) and the Saint Helena swamphen (Aphanocrex podarces) were once considered congeners of A. rogersi. The Ascension crake disappeared some time before 1700 but was briefly mentioned and described by traveller and hobby naturalist Peter Mundy in 1656. The Saint Helena swamphen disappeared before 1600 and has never been encountered alive by scientists. In 1973 Olson synonymised the genus Aphanocrex with the genus Atlantisia, and described the Ascension crake as being congeneric. Today they are considered to have evolved independently (with A. podarces probably not even being closely related), and in 2003 the genus Mundia was erected and the Saint Helena swamphen moved back to Aphanocrex, leaving the Inaccessible Island rail the only species in the genus Atlantisia. Both the Ascension crake and the Saint Helena swamphen became extinct due to predation by introduced species, mainly cats and rats. Stervander et al. (2019) resolved the taxonomic affinity and evolutionary history of the Inaccessible Island rail by phylogenetic analyses of the DNA sequence of its full mitochondrial genome and a handful mitochondrial and nuclear genetic markers. According to this study, the Inaccessible Island rail belongs to a clade comprising its sister species, the dot-winged crake, the black rail (Laterallus jamaicensis) in America, and most likely the Galápagos crake (Laterallus spilonota), therefore suggested referring the Inaccessible Island rail to the genus Laterallus. It colonized Inaccessible Island from South America c. 1.5 million years ago. Morphology The Inaccessible Island rail is the smallest living flightless bird in the world, measuring . Males are larger and heavier than females, weighing , average , compared to , average , in females. It is dark chestnut-brown above and dark grey on the head and below, with degraded white barring on the flanks and belly, and adults have a red eye. The female is similar to the male but with paler grey and a faint brown wash on the underparts. It has a black bill, which is shorter than the head. The feathers of the Inaccessible Island rail are almost hair-like, and