The small-billed moa-nalo (''Ptaiochen pau''), also known as the stumbling moa-nalo, is a 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 ...

, one of 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 North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north'' is ...

. It was described in 1991 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 in September 1982 by

Storrs Olson Storrs Lovejoy Olson (April 3, 1944 – January 20, 2021) was an American biologist and ornithologist who spent his career at the Smithsonian Institution, retiring in 2008. One of the world's foremost avian paleontologists, he was best known ...

Helen James Helen Frances James (born May 22, 1956) is an American paleontologist and paleornithologist who has published extensively on the fossil birds of the Hawaiian Islands. She is the curator in charge of birds in the Department of Vertebrate Zool ...

and others, from the Auwahi Cave on the southern slopes of

Haleakalā Haleakalā (; Hawaiian: ), or the East Maui Volcano, is a massive shield volcano that forms more than 75% of the Hawaiian Island of Maui. The western 25% of the island is formed by another volcano, Mauna Kahalawai, also referred to as the West ...

, on the 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 ...

Etymology

The generic name ''Ptaiochen'' links the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

' (“stumble”), with ''chen'' (“goose”), alluding to a fancied propensity of the species to fall into holes (thereby becoming part of the fossil record). The specific

epithet An epithet (, ), also byname, is a descriptive term (word or phrase) known for accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, di ...

is from the Hawaiian ''pau'' (“finished” or “destroyed”), referring to its extinction.

Description

The species was similar to moa-nalo in the genus ''

Thambetochen Thambetochen is an extinct genus of moa-nalo duck. It contains two species, the Maui Nui moa-nalo (''T. chauliodous'') and the smaller O'ahu moa-nalo (''T. xanion''). The former was found on Maui and Molokai on Hawaii, the latter was found ...

'' in having bony, tooth-like projections on the jaws. However, it differed in other aspects of skull morphology, such as in having a proportionately shorter and deeper

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ships * Ros ...

(though nothing like as deep as that of the

turtle-jawed moa-nalo The turtle-jawed moa-nalo (''Chelychelynechen quassus''), also formerly referred to as the large Kauai goose, is a species of moa-nalo, one of a group of extinct, flightless, large goose-like ducks, which evolved in the Hawaiian Islands of the N ...

Kauai Kauai, () anglicized as Kauai ( ), is geologically the second-oldest of the main Hawaiian Islands (after Niʻihau). With an area of 562.3 square miles (1,456.4 km2), it is the fourth-largest of these islands and the 21st largest island ...

), a more rounded

cranium The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...

, and in lacking impressions of salt-glands.

Distribution

Subfossil remains have been found only at altitudes of over 1100 m on Haleakalā, from the Auwahi Cave at 1145 m to the upper Kipahulu Valley at 1860 m, being replaced at lower levels by the larger

Maui Nui large-billed moa-nalo 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 in the genus ''Thambetochen''. Moa-nalo are a group of extinct, flightless, large goose-like ducks, which ev ...

References

Anatidae Late Quaternary prehistoric birds Holocene extinctions Extinct birds of Hawaii Biota of Maui Extinct flightless birds

small-billed moa-nalo The small-billed moa-nalo (''Ptaiochen pau''), also known as the stumbling moa-nalo, is a species of moa-nalo, one of a group of extinct, flightless, large goose-like ducks, which evolved in the Hawaiian Islands of the North Pacific Ocean. It was ...

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