Chelychelynechen Thambetochen Ptaiochen The moa-nalo are a group of extinct aberrant, goose-like ducks that lived on the larger Hawaiian Islands, except Hawaiʻi itself, in the Pacific.

Contrary to the expectations of some scientists, the moa-nalo were not related to the large geese (Anserinae), such as the surviving nēnē, but instead to the dabbling ducks of the genus Anas, which includes the mallard.

The present DNA analysis' resolution is not high enough to determine their relationships to different species of Anas, but biogeography strongly suggests that their closest living relative is the widespread Pacific black duck.

A study of coprolites (fossil dung) of Thambetochen chauliodous found in Puʻu Naio Cave on lowland Maui has shown they were folivorous, at least in dry shrub or mesic forest habitats eating particularly fronds from ferns (possibly Asplenium nidus or Dryopteris wallichiana).

Like island taxa from Mauritius, New Zealand and Polynesia, the moa-nalo were unused to mammals and were easily predated on by hunters or the animals that were introduced and became feral, such as domestic pigs.