The Maui Nui large-billed moa-nalo (''Thambetochen chauliodous''), also known as the Maui Nui moa-nalo, is one of two species of

moa-nalo The moa-nalo are a group of extinct aberrant, goose-like ducks that lived on the larger Hawaiian Islands, except Hawaii itself, in the Pacific. They were the major herbivores on most of these islands until they became extinct after human settle ...

in the genus '' Thambetochen''. Moa-nalo are a group of

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

flightless Flightless birds are birds that through evolution lost the ability to fly. There are over 60 extant species, including the well known ratites (ostriches, emu, cassowaries, rheas, and kiwi) and penguins. The smallest flightless bird is the ...

, large goose-like

duck Duck is the common name for numerous species of waterfowl in the family Anatidae. Ducks are generally smaller and shorter-necked than swans and geese, which are members of the same family. Divided among several subfamilies, they are a form t ...

s, which

evolved Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation t ...

in the

Hawaiian Islands The Hawaiian Islands ( haw, Nā Mokupuni o Hawai‘i) are an archipelago of eight major islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some from the island of Hawaii in the south to northernmost Kur ...

of the North Pacific Ocean.

Distribution and habitat

The genus and species were originally described in 1976 from

subfossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...

material collected from the Moomomi Dunes, on the island of

Molokai Molokai , or Molokai (), is the fifth most populated of the eight major islands that make up the Hawaiian Islands, Hawaiian Islands archipelago in the middle of the Pacific Ocean. It is 38 by 10 miles (61 by 16 km) at its greatest length an ...

. Remains of the bird have also been recovered from Ilio Point on Molokai as well as from

lava tube A lava tube, or pyroduct, is a natural conduit formed by flowing lava from a volcanic vent that moves beneath the hardened surface of a lava flow. If lava in the tube empties, it will leave a cave. Formation A lava tube is a type of lava ca ...

s on the southern slopes of the volcanic mountain of Haleakalā on the nearby island of

Maui The island of Maui (; Hawaiian: ) is the second-largest of the islands of the state of Hawaii at 727.2 square miles (1,883 km2) and is the 17th largest island in the United States. Maui is the largest of Maui County's four islands, which ...

. Both Molokai and Maui are parts of what used to be the much larger prehistoric island of

Maui Nui Maui Nui or Greater Maui, is a modern geologists' name given to a prehistoric Hawaiian Island built from seven shield volcanoes. ''Nui'' means "great/large" in the Hawaiian language. 1.2 million years ago, Maui Nui was , 40% larger than the pre ...

, to which the species appears to have been endemic. The bird evidently shared the island with another moa-nalo—the smaller small-billed moa-nalo—which, from the sites from which its remains have been recovered, appears to have been largely restricted to upland areas over 1100 m in altitude, while the large-billed species occupied the lowlands. It was larger than its only congener, the O'ahu moa-nalo.

References

Anatinae Late Quaternary prehistoric birds Holocene extinctions Extinct birds of Hawaii Extinct flightless birds Biota of Maui Maui County, Hawaii Biota of Molokai Maui Nui large-billed moa-nalo Birds described in 1976 {{Anseriformes-stub