''Proapteryx micromeros'' is an extinct

kiwi Kiwi most commonly refers to: * Kiwi (bird), a flightless bird native to New Zealand * Kiwi (nickname), a nickname for New Zealanders * Kiwifruit, an edible berry * Kiwi dollar or New Zealand dollar, a unit of currency Kiwi or KIWI may also refe ...

known from the 16–19 million-year-old early

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

sediments of the

St Bathans Fauna The St Bathans fauna is found in the lower Bannockburn Formation of the Manuherikia Group of Central Otago, in the South Island of New Zealand. It comprises a suite of fossilised prehistoric animals from the late Early Miocene (Altonian) period, ...

Otago Otago (, ; mi, Ōtākou ) is a region of New Zealand located in the southern half of the South Island administered by the Otago Regional Council. It has an area of approximately , making it the country's second largest local government reg ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

Features

''P. micromeros'' is considerably smaller than modern kiwis, weighing around 234.1 – 377g (the smallest living kiwi, '' Apteryx owenii'', weighs at least 800 g), and its more gracile otic process may indicate a shorter bill. It bears distinctively slender hindlimbs, more comparable in terms of proportion to flying birds like the banded rail than to extant kiwis, and it is speculated to have been capable of powered flight, or to have evolved relatively recently from flying ancestors.

Importance

The fact that ''Proapteryx'' lacked specialisation for a terrestrial, flightless lifestyle supports the hypothesis that kiwi ancestors flew to New Zealand from

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

in the Miocene, well after

moa Moa are extinct giant flightless birds native to New Zealand. The term has also come to be used for chicken in many Polynesian cultures and is found in the names of many chicken recipes, such as Kale moa and Moa Samoa. Moa or MOA may also refe ...

s had developed their modern forms – moa remains are also known from Saint Bathans, already large and flightless.Worthy, T.H., Tennyson, A.J.D., Jones, C., McNamara, J.A. & Douglas B.J. (2007). "Miocene waterfowl and other birds from Central Otago, New Zealand". ''Journal of Systematic Palaeontology'', 5: 1–39. This supports genetic and morphological analyses indicating that the two clades arrived in New Zealand independently and are not particularly closely related, moas forming a clade with

tinamou Tinamous () form an order of birds called Tinamiformes (), comprising a single family called Tinamidae (), divided into two distinct subfamilies, containing 46 species found in Mexico, Central America, and South America. The word "tinamou" come ...

s, and kiwis with Australian

ratite A ratite () is any of a diverse group of flightless, large, long-necked, and long-legged birds of the infraclass Palaeognathae. Kiwi, the exception, are much smaller and shorter-legged and are the only nocturnal extant ratites. The systematics ...

s, the

cassowary Cassowaries ( tpi, muruk, id, kasuari) are flightless birds of the genus ''Casuarius'' in the order Casuariiformes. They are classified as ratites (flightless birds without a keel on their sternum bones) and are native to the tropical forest ...

and

emu The emu () (''Dromaius novaehollandiae'') is the second-tallest living bird after its ratite relative the ostrich. It is endemic to Australia where it is the largest native bird and the only extant member of the genus ''Dromaius''. The emu' ...

.Phillips, M.J., Gibb, G.C., Crimp, E.A. & Penny, D. (2010). "Tinamous and moa flock together: mitochondrial genome sequence analysis reveals independent losses of flight among ratites". ''Systematic Biology'', 59: 90–107. Kiwis have also been found by molecular studies to be the sister taxa of the

elephant bird Elephant birds are members of the extinct ratite family Aepyornithidae, made up of flightless birds that once lived on the island of Madagascar. They are thought to have become extinct around 1000-1200 CE, probably as a result of human activity. ...

s of

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

. ''Proapteryx'' establishes the existence of flying Australian

palaeognath Palaeognathae (; ) is a infraclass of birds, called paleognaths, within the class Aves of the clade Archosauria. It is one of the two extant infraclasses of birds, the other being Neognathae, both of which form Neornithes. Palaeognathae contain ...

s as recently as the early Miocene, indicating that the Malagasy ratites may have flown across the Indian Ocean around this time.

References

{{Taxonbar, from=Q16757705 Paleognathae Ratites Miocene birds Fossils of New Zealand Birds of the South Island Extinct birds of New Zealand Endemic fauna of New Zealand Fossil taxa described in 2013 Extinct monotypic bird genera Endemic birds of New Zealand