Another case of island gigantism: the extinct Hodgens’ Waterhen (Tribonyx hodgenorum) is a member of Porzana (Aves: Rallidae)

Tribonyx hodgenorum (Scarlett, Rec Canterb Mus 6:265–266, 1955) was a flightless rail (Rallidae) endemic to Aotearoa New Zealand that became extinct in the eighteenth century. The affinities of this rail have puzzled taxonomists, who have placed it in no less than six different genera. We present molecular phylogenetic evidence based on mitochondrial data that places T. hodgenorum within the Porzana clade as the sister taxon of Australian Crake (P. fluminea). This position was strongly supported but was not previously suspected. Thus, rather than a moderately small species of native-hen (Tribonyx), T. hodgenorum is a giant species of crake (Porzana). After the recent re-allocation of several species of ‘Porzana’ to other genera, P. hodgenorum is the only known flightless species of Porzana. The genus name Pyramida Oliver, 1955, which is no longer in use, becomes a junior synonym of Porzana Vieillot, 1816. We suggest changing the English name of P. hodgenorum from Hodgens’ Waterhen or New Zealand Native-hen to New Zealand Giant Crake.