The pygmy geese are a group of very small "perching duck

Perching duck

The perching ducks were previously treated as a small group of ducks in the duck, goose and swan family Anatidae, grouped together on the basis of their readiness to perch high in trees...

s" in the genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Nettapus which breed in the Old World tropics. They are the smallest of all wildfowl

Anseriformes

The order Anseriformes contains about 150 living species of birds in three extant families: the Anhimidae , Anseranatidae , and the Anatidae, which includes over 140 species of waterfowl, among them the ducks, geese, and swans.All species in the order are highly adapted for an aquatic existence at...

. As the "perching ducks" are a paraphyletic group, they need to be placed elsewhere. The initially assumed relationship with the dabbling duck subfamily Anatinae has been questioned, and it appears they form a lineage in an ancient Gondwana

Gondwana

In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...

n radiation of waterfowl, within which they are of unclear affinities. An undescribed fossil species from the late Hemphillian (5.0-4.1 mya) of Jalisco

Jalisco

Jalisco officially Estado Libre y Soberano de Jalisco is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is located in Western Mexico and divided in 125 municipalities and its capital city is Guadalajara.It is one of the more important states...

, central Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

, has also been identified from the distal end of a tarsometatarsus. It is only record of the genus in the New World.

There are three extant species in the genus:

• Green Pygmy Goose
  Green Pygmy Goose
  The Green Pygmy Goose is a small perching duck which breeds in southern New Guinea and northern Australia.First described in 1842 by the ornithologist John Gould, its specific name is derived from diminutive of the Latin adjective pulcher "pretty". It is one of three species in the Afro-Asian...
  
    Nettapus pulchellus of northern Australia
  Australia
  Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
  
   and southern New Guinea
  New Guinea
  New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
  
  .
• Cotton Pygmy Goose
  Cotton Pygmy Goose
  The Cotton Pygmy Goose or the Cotton Teal, Nettapus coromandelianus is a small perching duck which breeds in Pakistan, India, Bangladesh, southeast Asia and south to northern Australia.-Description:...
  
    Nettapus coromandelianus of Southeast Asia
  Southeast Asia
  Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
  
  .
• African Pygmy Goose
  African Pygmy Goose
  The African Pygmy Goose is a very small perching duck from sub-Saharan Africa. It has been featured in many Vietnamese pornographic films. It is the smallest African waterfowl. It is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds applies....
  
    Nettapus auritus of sub-Saharan Africa
  Africa
  Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
  
  .

Their habitat is still freshwater lakes, where these neat duck

Duck

Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...

s feed on seeds and other vegetation, especially water lilies

Nymphaeaceae

Nymphaeaceae is a family of flowering plants. Members of this family are commonly called water lilies and live in freshwater areas in temperate and tropical climates around the world. The family contains eight genera. There are about 70 species of water lilies around the world. The genus...

.

Pygmy geese have short bills, rounded heads and short legs. They nest in tree holes.