Two forms of a large and flightless rail (takahe) belonging to the gen
us Porphyrio and endemic to New Zealand have been described, although
their taxonomy has been repeatedly questioned. Analyses of osteometric
data from modern and Quaternary fossil material show such a degree of
allometric distinctiveness that it is considered that the two forms a
re, indeed, different species as originally described, Porphyrio mante
lli (Owen), Porphyrio hochstetteri (Meyer). It is suggested that this
degree and type of difference could have resulted from the two species
arising independently from similar volant ancestors.