Megavitiornis Temporal range: Holocene
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Family:	†Sylviornithidae
Genus:	†Megavitiornis
Species:	†M. altirostris
Binomial name
†Megavitiornis altirostris Worthy, 2000[1]

Megavitiornis altirostris is an extinct, flightless, giant stem-galliform bird that was endemic to Fiji, it is the only known species in the genus Megavitiornis. Originally thought to be a megapode, more recent morphological studies indicate a close relationship with Sylviornis of New Caledonia, with both genera belonging to the family Sylviornithidae outside of the Galliformes crown group.^[2] It is likely that it became extinct through overhunting shortly after the colonisation of the Fiji Islands by humans.^[1]

The genus is monotypic, with the generic name Megavitiornis derived from the Greek mega (great), viti (Fiji), and ornis (bird). The specific epithet altirostris comes from Latin altus (high or noble), and rostrum (bill), referring to the extraordinarily large vertical dimension of its bill. Worthy also suggested “Noble Megapode” would be an appropriate vernacular name for the bird.^[1]

It was described by New Zealand palaeontologist Trevor Worthy in October 1998 from subfossil remains collected by Worthy, G. Udy and S. Mataraba. Sites containing remains include the Udit Tomo cave at Wainibuku, Voli Voli and Delai-ni-qara caves on the island of Viti Levu, as well as on Naigani Island. The holotype is held by the Museum of New Zealand (reg. no: S.037362). In its time it was probably the largest bird in Fiji.

The bird's flightlessness is evident in its large body size, the extreme reduction of pectoral girdle elements and the loss of a keel on the sternum. The size and proportions of the bill are unlike those of any living fowl and, with a depth of 28% of the length, extraordinarily deep compared to modern galliforms. Worthy speculates that it was used for cracking the hard seeds of large forest fruits; there are several tropical forest trees native to Fiji producing hard seeds that cannot be cracked by any living birds or bats in the islands.^[1][3]

v t e Genera of landfowl and their extinct allies
Kingdom: Animalia Phylum: Chordata Class: Aves Superorder: Galloanserae Clade: Pangalliformes
Pangalliformes incertae sedis †Anisolornis? †Archaeophasianus? †Argillipes? †Austinornis? †Chambiortyx †Coturnipes? †"Gigantibis"? †Litoripes? †Percolinus? †Tegulavis? †Gallinuloididae Gallinuloides Paraortygoides †Paraortygidae Paraortyx Pirortyx Scopelortyx Xorazmortyx †Quercymegapodiidae Ameripodius Quercymegapodius Taubacrex †Sylviornithidae Megavitiornis Sylviornis Galliformes See below ↓
Galliformes Galliformes †Amitabha †Bumbanipodius †Bumbanortyx †Linquornis †Namaortyx †Palaeoalectoris †Procrax †Sobniogallus †Taoperdix Megapodiidae †Garrdimalga? †Mwalau †Ngawupodius Alecturini Aepypodius Alectura †Latagallina Leipoa †Progura Talegalla Megapodiini Eulipoa Macrocephalon Megapodius Cracidae †Archaealectrornis †Boreortalis †Palaeonossax †Procrax Penelopinae Aburria Chamaepetes Penelope Penelopina Pipile Cracinae Oreophasis Ortalis Cracini Crax Mitu Nothocrax Pauxi Phasianoidea See below ↓
Phasianoidea Numididae Acryllium Agelastes Guttera Numida †Telecrex Odontophoridae †Miortyx †Nanortyx †Neortyx Ptilopachinae Ptilopachus Odontophorinae Callipepla Colinus Cyrtonyx Dactylortyx Dendrortyx Odontophorus Oreortyx Philortyx Rhynchortyx Phasianidae See below ↓
Phasianidae Phasianidae †Bantamyx †Centuriavis †Diangallus †Eurobambusicola †Lophogallus †Megalocoturnix †Miogallus †Mioryaba †Palaeocryptonyx †Palaeortyx †Panraogallus †Pliogallus †Plioperdix †Rustaviornis †Schaubortyx †Shandongornis †Shanxiornis †Titanoperdix †Tologuica Rollulinae Arborophila Caloperdix Melanoperdix Rhizothera Rollulus Xenoperdix Pavoninae Tropicoperdix Coturnicini Alectoris Ammoperdix Coturnix Margaroperdix †?Ophrysia Perdicula Pternistis Synoicus Tetraogallus Gallini Bambusicola Campocolinus Francolinus Gallus Ortygornis Peliperdix Scleroptila Pavonini Afropavo Argusianus Pavo Rheinardia Polyplectronini Galloperdix Haematortyx Polyplectron Phasianinae †Chauvireria Ithaginis Lerwa Lophophorini Lophophorus Tetraophasis Tragopan Phasianini Catreus Chrysolophus Crossoptilon Lophura Perdix Phasianus Syrmaticus Tetraonini Bonasa Canachites Centrocercus Dendragapus Falcipennis Lagopus Lyrurus Meleagris †Palaealectoris †Proagriocharis Pucrasia †Rhegminornis Tetrao Tetrastes Tympanuchus