PalaeognathaePalaeognathae (ˌpæliˈɒgnəθi; ) is a infraclass of birds, called paleognaths or palaeognaths, 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 contains five extant branches of flightless lineages (plus two extinct clades), termed ratites, and one flying lineage, the Neotropic tinamous.
Flightless birdFlightless 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 Inaccessible Island rail (length 12.5 cm, weight 34.7 g). The largest (both heaviest and tallest) flightless bird, which is also the largest living bird in general, is the ostrich (2.7 m, 156 kg).
Common ostrichThe common ostrich (Struthio camelus), or simply ostrich, is a species of flightless bird native to certain large areas of Africa. It is one of two extant species of ostriches, the only living members of the genus Struthio in the ratite order of birds. The other is the Somali ostrich (Struthio molybdophanes), which was recognized as a distinct species by BirdLife International in 2014 having been previously considered a distinctive subspecies of ostrich. The common ostrich belongs to the order Struthioniformes.
Andean condorThe Andean condor (Vultur gryphus) is a giant South American Cathartid vulture and is the only member of the genus Vultur. Found in the Andes mountains and adjacent Pacific coasts of western South America, the Andean condor is the largest flying bird in the world by combined measurement of weight and wingspan. It has a maximum wingspan of and weight of . It is generally considered to be the largest bird of prey in the world. It is a large black vulture with a ruff of white feathers surrounding the base of the neck and, especially in the male, large white patches on the wings.
Great American InterchangeThe Great American Biotic Interchange (commonly abbreviated as GABI), also known as the Great American Interchange and the Great American Faunal Interchange, was an important late Cenozoic paleozoogeographic biotic interchange event in which land and freshwater fauna migrated from North America via Central America to South America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor and bridged the formerly separated continents. Although earlier dispersals had occurred, probably over water, the migration accelerated dramatically about 2.
EnantiornithesThe Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and clawed fingers on each wing, but otherwise looked much like modern birds externally. Over eighty species of Enantiornithes have been named, but some names represent only single bones, so it is likely that not all are valid.
EmuThe emu (ˈiːmjuː; 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's range covers most of the mainland, but the Tasmanian, Kangaroo Island and King Island subspecies became extinct after the European settlement of Australia in 1788. Emus are soft-feathered, brown, flightless birds with long necks and legs, and can reach up to in height.
CassowaryCassowaries (muruk, 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. Cassowaries are native to the tropical forests of New Guinea (Papua New Guinea and West Papua), the Aru Islands (Maluku), and northeastern Australia. Three cassowary species are extant. The most common, the southern cassowary, is the third-tallest and second-heaviest living bird, smaller only than the ostrich and emu.
MoaMoa (order Dinornithiformes) are an extinct group of flightless birds formerly endemic to New Zealand. During the Late Pleistocene-Holocene, there were nine species (in six genera). The two largest species, Dinornis robustus and Dinornis novaezelandiae, reached about in height with neck outstretched, and weighed about while the smallest, the bush moa (Anomalopteryx didiformis), was around the size of a turkey. Estimates of the moa population when Polynesians settled New Zealand circa 1300 vary between 58,000 and approximately 2.
MegafaunaIn zoology, megafauna (from Greek μέγας megas "large" and Neo-Latin fauna "animal life") are large animals. The most common thresholds to be a megafauna are weighing over (i.e., having a mass comparable to or larger than a human) or weighing over a tonne, (i.e., having a mass comparable to or larger than an ox). The first of these include many species not popularly thought of as overly large, and being the only few large animals left in a given range/area, such as white-tailed deer, Thomson's gazelle, and red kangaroo.
