Galliformes is an order of heavy-bodied ground-feeding birds that includes turkeys, chickens, quails, and other landfowl. Gallinaceous birds, as they are called, are important as seed dispersers and predators in the ecosystems they inhabit, and are often reared by humans for their meat and eggs, or hunted as game birds.
A ratite is any of a diverse group of mostly flightless, large, and long-legged birds of the infraclass Palaeognathae. Kiwi, the exception, are much smaller and shorter-legged, as well as being the only nocturnal extant ratites.
The rails, or Rallidae, are a large cosmopolitan family of small- to medium-sized, ground-living birds. The family exhibits considerable diversity and includes the crakes, coots, and gallinules. Many species are associated with wetlands, although the family is found in every terrestrial habitat except dry deserts, polar regions, and alpine areas above the snow line. Members of the Rallidae occur on every continent except Antarctica. Numerous island species are known. The most common rail habitats are marshland and dense forest. They are especially fond of dense vegetation.
The New Zealand wrens are a family (Acanthisittidae) of tiny passerines endemic to New Zealand. They were represented by six known species in four or five genera, although only two species survive in two genera today. They are understood to form a distinct lineage within the passerines, but authorities differ on their assignment to the oscines or suboscines. More recent studies suggest that they form a third, most ancient, suborder Acanthisitti and have no living close relatives at all. They are called "wrens" due to similarities in appearance and behaviour to the true wrens (Troglodytidae), but are not members of that family.
Struthionidae is a family of flightless birds, containing the extant ostriches and their extinct relatives. The two extant species of ostrich are the common ostrich and Somali ostrich, both in the genus Struthio, which also contains several species known from Holocene fossils such as the Asian ostrich. The common ostrich is the more widespread of the two living species, and is the largest living bird species. Other ostriches are also among the largest bird species ever.
Flightless birds are birds that through evolution lost the ability to fly. There are over 60 extant species, including the well known ratites and penguins. The smallest flightless bird is the Inaccessible Island rail. The largest flightless bird, which is also the largest living bird, is the ostrich.
Dromornithidae, known as mihirungs and informally as thunder birds or demon ducks, were a clade of large, flightless Australian birds of the Oligocene through Pleistocene Epochs. All are now extinct. They were long classified in Struthioniformes, but are now usually classified as galloanseres.
Dromornis is a genus of large to enormous prehistoric birds. The species were flightless, possessing greatly reduced wing structures but with large legs, similar to the modern ostrich or emu. They were likely to have been predominately, if not exclusively, herbivorous browsers. The male of the largest species, Dromornis stirtoni, is a contender for the tallest and heaviest bird, and possibly exhibited aggressive territorial behaviour.
Palaeognathae is a clade of birds, called paleognaths, within the subclass Neornithes of the class Aves. 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, termed ratites, and one flying lineage, the Neotropic tinamous. There are forty-seven species of tinamous, five of kiwis (Apteryx), three of cassowaries (Casuarius), one of emus (Dromaius), two of rheas (Rhea) and two of ostrich (Struthio). Recent research has indicated that paleognaths are monophyletic but the traditional taxonomic split between flightless and flighted forms is incorrect; tinamous are within the ratite radiation, meaning flightlessness arose independently multiple times via parallel evolution.
The evolution of birds began in the Jurassic Period, with the earliest birds derived from a clade of theropod dinosaurs named Paraves. Birds are categorized as a biological class, Aves. For more than a century, the small theropod dinosaur Archaeopteryx lithographica from the Late Jurassic period was considered to have been the earliest bird. Modern phylogenies place birds in the dinosaur clade Theropoda. According to the current consensus, Aves and a sister group, the order Crocodilia, together are the sole living members of an unranked "reptile" clade, the Archosauria. Four distinct lineages of bird survived the Cretaceous–Paleogene extinction event 66 million years ago, giving rise to ostriches and relatives (Paleognathae), ducks and relatives (Anseriformes), ground-living fowl (Galliformes), and "modern birds" (Neoaves).
Sylviornis is an extinct genus of large, flightless bird that was endemic to the islands of New Caledonia in the Western Pacific. It is considered to constitute one of two genera in the extinct family Sylviornithidae, alongside Megavitiornis from Fiji, which are related to the Galliformes, the group containing the turkeys, chickensquails and pheasants. Sylviornis was never encountered alive by scientists, but it is known from many thousands of subfossil bones found in deposits, some of them from the Holocene, on New Caledonia and the adjacent Île des Pins. It was likely hunted to extinction shortly after the first human arrival to New Caledonia around 1500 BC.
Gastornithiformes were an extinct order of giant flightless fowl with fossils found in North America, Eurasia, and possibly Australia. Members of Gastornithidae were long considered to be a part of the order Gruiformes. However, the traditional concept of Gruiformes has since been shown to be an unnatural grouping.
Lithornithidae is an extinct, possibly paraphyletic group of early paleognath birds. They are known from fossils dating to the Upper Paleocene through the Middle Eocene of North America and Europe, with possible Late Cretaceous representatives. All are extinct today; the youngest specimen is the currently unnamed SGPIMH MEV1 specimen from the mid-Eocene Messel Pit site.
Pangalliformes is the scientific name of a provisional clade of birds within the group Galloanserae. It is defined as all birds more closely related to chickens than to ducks, and includes all modern chickens, turkeys, pheasants, and megapodes, as well as extinct species that do not fall within the crown group Galliformes.
Megavitiornis altirostris is an extinct, flightless, giant stem-galliform bird that was endemic to Fiji, it is the only known species in the genus Megavitornis. Originally thought to be a megapode, more recent morphological studies indicate a close relationship with Sylviornis of New Caledonia, with both genera belonging to the family Sylviornithidae outside of the Galliformes crown group. It is likely that it became extinct through overhunting shortly after the colonisation of the Fiji Islands by humans.
The Odontoanserae is a proposed clade that includes the family Pelagornithidae and the clade Anserimorphae. The placement of the pseudo-toothed birds in the evolutionary tree of birds has been problematic, with some supporting the placement of them near the orders Procellariformes and Pelecaniformes based on features in the sternum.
Geranoididae is a clade of extinct palaeognathae birds from the early to late Eocene and possibly early Oligocene of North America and Europe. These were mid-sized, long-legged flightless birds, superficially similar but unrelated to modern ratites. However, a recent study shows that these birds may actually be palaeognaths related to ostriches.
Palaeophasianus is an extinct genus of flightless Geranoididae birds that lived in North America during the Eocene period. Robert Wilson Shufeldt classified Palaeophasianus as a galliform when he described it in 1913. However it was transferred to Cracidae in 1964 by Pierce Brodkorb, while Joel Cracraft in 1968 placed it in Gruiformes.
