Galliformes

Galliformes is an order of heavy-bodied ground-feeding birds that includes turkey, grouse, chicken, New World quail and Old World quail, ptarmigan, partridge, pheasant, francolin, junglefowl and the Cracidae. The name derives from 'gallus', Latin for 'cock' or 'rooster'. Common names are gamefowl or gamebirds, landfowl, gallinaceous birds, or galliforms. 'Wildfowl' or just 'fowl' are also often used for the Galliformes, but usually these terms also refer to waterfowl (Anseriformes), and occasionally to other commonly hunted birds. This group has about 290 species, one or more of which are found in essentially every part of the world's continents (except for the innermost deserts and perpetual ice). They are rarer on islands, and in contrast to the closely related waterfowl, are essentially absent from oceanic islands—unless introduced there by humans. Several species have been domesticated during their long and extensive relationships with humans. This order contains five families: Phasianidae (including chicken, quail, partridges, pheasants, turkeys, peafowl and grouse), Odontophoridae (New World quails), Numididae (guineafowl), Cracidae (including chachalacas and curassows), and Megapodiidae (incubator birds like mallee fowl and brush-turkeys). They are important as seed dispersers and predators in the ecosystems they inhabit, and are often reared as game birds by humans for their meat and eggs and for recreational hunting. Many gallinaceous species are skilled runners and escape predators by running rather than flying. Males of most species are more colorful than the females. Males often have elaborate courtship behaviors that include strutting, fluffing of tail or head feathers, and vocal sounds. They are mainly nonmigratory. The living Galliformes were once divided into seven or more families. Despite their distinctive appearance, grouse and turkeys probably do not warrant separation as families due to their recent origin from partridge- or pheasant-like birds. The turkeys became larger after their ancestors colonized temperate and subtropical North America, where pheasant-sized competitors were absent. The ancestors of grouse, though, adapted to harsh climates and could thereby colonize subarctic regions. Consequently, the Phasianidae are expanded in current taxonomy to include the former Tetraonidae and Meleagrididae as subfamilies. The Anseriformes (waterfowl) and the Galliformes together make up the Galloanserae. They are basal among the living neognathous birds, and normally follow the Paleognathae (ratites and tinamous) in modern bird classification systems. This was first proposed in the Sibley-Ahlquist taxonomy and has been the one major change of that proposed scheme that was almost universally adopted. However, the Galliformes as they were traditionally delimited are called Gallomorphae in the Sibley-Ahlquist taxonomy, which splits the Cracidae and Megapodiidae as an order 'Craciformes'. This is not a natural group, however, but rather an erroneous result of the now-obsolete phenetic methodology employed in the Sibley-Ahlquist taxonomy. Phenetic studies do not distinguish between plesiomorphic and apomorphic characters, which leads to basal lineages appearing as monophyletic groups. Historically, the buttonquails (Turnicidae), mesites (Mesitornithidae) and the hoatzin (Opisthocomus hoazin) were placed in the Galliformes, too. The former are now known to be shorebirds adapted to an inland lifestyle, whereas the mesites are probably closely related to pigeons and doves. The relationships of the hoatzin are entirely obscure, and it is usually treated as a monotypic order Opisthocomiformes to signify this. Galliform-like birds were one of the main survivors of the K-T Event that killed off the rest of the dinosaurs. They were a niche group that were toothless and ground-dwelling, unlike the dominant birds of the era called the enantiornithes, which had teeth and dominated the trees and skies. Fossils of these galliform-like birds originate in the Late Cretaceous, most notably those of Austinornis lentus. Its partial left tarsometatarsus was found in the Austin Chalk near Fort McKinney, Texas, dating to about 85 million years ago (Mya). This bird was quite certainly closely related to Galliformes, but whether it was a part of these or belongs elsewhere in the little-known galliform branch of Galloanserae is not clear. However, in 2004, Clarke classified it as a member of the larger group Pangalliformes, more closely related to chickens than to ducks, but not a member of the crown group that includes all modern galliformes. Another specimen, PVPH 237, from the Late Cretaceous Portezuelo Formation (Turonian-Coniacian, about 90 Mya) in the Sierra de Portezuelo (Argentina) has also been suggested to be an early galliform relative. This is a partial coracoid of a neornithine bird, which in its general shape and particularly the wide and deep attachment for the muscle joining the coracoid and the humerus bone resembles the more basal lineages of galliforms. It is believed that an asteroid impact killed off all dinosaurs, including the dominant birds, during the K-T event, destroying all creatures that lived in trees and on open ground. While the more successful enantiornithes were wiped out, the ancestors of galliformes were small and lived in the ground or water. This protected them from the blast and destruction.