''Branta rhuax'', the giant Hawaii goose, is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

goose endemic to the island of

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

. It was initially described as the monotypic genus ''Geochen'', but then reassigned to '' Branta'' by Storrs L. Olson in 2013 after reexamination of the subfossil material.

Taxonomy

The bird was described in 1943 by Alexander Wetmore from subfossil remains originally discovered in 1926, in the course of a public works excavation of a water supply tunnel. The bones were found at a depth of 25 m beneath a prehistoric

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

flow, on top of an ash bed, near Kaumaikeohu, above Pahala in the Kau District of the Island of

. The bones are friable and warped, having been subjected to intense heat from the lava. The specific

epithet An epithet (, ), also a byname, is a descriptive term (word or phrase) commonly accompanying or occurring in place of the name of a real or fictitious person, place, or thing. It is usually literally descriptive, as in Alfred the Great, Suleima ...

comes from the Greek ''rhuax'' (lava stream). The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

is a fragmentary right

tibiotarsus The tibiotarsus is the large bone between the femur and the tarsometatarsus in the leg of a bird. It is the fusion of the proximal part of the tarsus with the tibia. A similar structure also occurred in the Mesozoic Heterodontosauridae. These ...

(USNM V16740) held by the United States

National Museum of Natural History The National Museum of Natural History (NMNH) is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. With 4.4 ...

in Washington D.C. It was the first fossil bird to be described from the Hawaiian Islands. In his 1943 description Wetmore opined that the bird most resembled the Cape Barren goose of southern

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, and was about the same size. However, subsequently Olson and James (1991) considered that the available material was too imperfect for determining the affinities so precisely and that the relationships of the bird would remain doubtful until further specimens were obtained. The type material was later reexamined and determined to be the same species as an unnamed large, flightless, extinct ''Branta'' goose known from elsewhere on the island of Hawaii, and therefore ''Geochen rhuax'' was reassigned to the genus ''Branta''.

References

Extinct birds of Hawaii Holocene extinctions Fossil taxa described in 1943 rhuax Biota of Hawaii (island) Late Quaternary prehistoric birds Birds described in 1943 Taxa named by Alexander Wetmore {{goose-stub