Neognathae
Encyclopedia
Neognaths are bird
s within the subclass
Neornithes of the class
Aves. The Neognathae include virtually all living birds; their sister taxon Palaeognathae contains the tinamous and the flightless ratite
s.
There are nearly 10,000 species
of neognaths. Since the late Cretaceous
, from which the earliest fossil
s are known, they have undergone an adaptive radiation producing the diversity of form, function, and behavior that we see today. The Passeriformes (perching birds) are the largest order of land vertebrates, containing some 60% of living birds and being more than twice as speciose as rodent
s and about 5 times as speciose as Chiroptera (bats and flying foxes) which are the largest orders of mammal
s. On the other hand, there are some very small orders, usually birds of very unclear relationships like the puzzling Hoatzin
.
The neognaths have fused metacarpals, an elongate third finger, and 13 or fewer vertebrae. They differ from the Palaeognathae in features like the structure of their jawbones. "Neognathae" means "new jaws", but ironically it seems that the supposedly "more ancient" paleognath jaws are among the few apomorphic (more derived) features of this group as compared to the neognaths.
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For long the Neognathae were ranked
as a superorder and not subdivided any further; attempts to do so, for example in the Conspectus of Charles Lucien Bonaparte
, were never accepted even by a significant majority of ornithologists. Indeed, until the 1980s there was little subdivision of the Aves in general, and even less of phylogenetic merit. Since then the availability of massive amounts of new data from fossil
s - especially Enantiornithes
and other Mesozoic
birds - as well as molecular (DNA
and protein
) sequences allowed scientists to refine the classification. With new groups of neognath orders being verified, the taxonomic rank of the group needed to shift. In fact, most researchers have by now employed the unranked taxa of phylogenetic nomenclature
.
The Neognathae are universally accepted to subdivide into two lineages - the "fowl" clade Galloanseres and the Neoaves (sometimes called "higher neognaths"). The subdivisions of the latter are still not well resolved, but several monophyletic lineages have been proposed, such as the Mirandornithes
, Cypselomorphae
or Metaves and Coronaves. While groups such as the former two - uniting a few closely related orders - are robustly supported, this cannot be said for the Metaves-Coronaves division for which there is no material evidence at present while the Mesozoic
record of Neognathae is at present utterly devoid of birds that would have to be present if these proposed clades were real.
Taxonomic note:
The ranks used here are rarely employed in the literature. The ultimate reason is a limitation in the Wikipedia taxobox code, which does not allow for an arbitrary number of "unranked" taxa to be displayed. As the taxa used here have all been validly described and neither the ICZN
nor any other authority regulates their employment, the present ranking is as valid as any other - perhaps even more - and given the technical limitations the only system that can currently be used within the scope of Wikipedia. More commonly found is the old placement as a superorder - but such systematic treatments need to be viewed with caution, as they often do not even incorporate the Galloanserae - or as unranked clade
.
as well as from the Sibley-Ahlquist taxonomy
, combining those elements from each that more modern research agrees with while updating those that are refuted. The result is at least a much better representation of the true evolutionary relationships of neognath orders. Most of the changes affect those "higher landbirds" that are sometimes united as near passerine
s.
mobility increased due to the following modifications (Feduccia 1980, 1996):
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s within the subclass
Class (biology)
In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...
Neornithes of the class
Class (biology)
In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...
Aves. The Neognathae include virtually all living birds; their sister taxon Palaeognathae contains the tinamous and the flightless ratite
Ratite
A ratite is any of a diverse group of large, flightless birds of Gondwanan origin, most of them now extinct. Unlike other flightless birds, the ratites have no keel on their sternum—hence the name from the Latin ratis...
s.
There are nearly 10,000 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of neognaths. Since the late Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
, from which the earliest fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s are known, they have undergone an adaptive radiation producing the diversity of form, function, and behavior that we see today. The Passeriformes (perching birds) are the largest order of land vertebrates, containing some 60% of living birds and being more than twice as speciose as rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
s and about 5 times as speciose as Chiroptera (bats and flying foxes) which are the largest orders of mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s. On the other hand, there are some very small orders, usually birds of very unclear relationships like the puzzling Hoatzin
Hoatzin
The Hoatzin , also known as the Hoactzin, Stinkbird, or Canje Pheasant, is a species of tropical bird found in swamps, riverine forest and mangrove of the Amazon and the Orinoco delta in South America...
.
The neognaths have fused metacarpals, an elongate third finger, and 13 or fewer vertebrae. They differ from the Palaeognathae in features like the structure of their jawbones. "Neognathae" means "new jaws", but ironically it seems that the supposedly "more ancient" paleognath jaws are among the few apomorphic (more derived) features of this group as compared to the neognaths.
Taxonomy and systematics
Taxonomic rank
In biological classification, rank is the level in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, and class. Each rank subsumes under it a number of less general categories...
as a superorder and not subdivided any further; attempts to do so, for example in the Conspectus of Charles Lucien Bonaparte
Charles Lucien Bonaparte
Charles Lucien Jules Laurent Bonaparte, 2nd Prince of Canino and Musignano was a French naturalist and ornithologist.-Biography:...
, were never accepted even by a significant majority of ornithologists. Indeed, until the 1980s there was little subdivision of the Aves in general, and even less of phylogenetic merit. Since then the availability of massive amounts of new data from fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s - especially Enantiornithes
Enantiornithes
Enantiornithes is an extinct group of primitive birds. They were the most abundant and diverse avialans of the Mesozoic. Almost all retained teeth and clawed fingers on each wing, but otherwise looked much like modern birds externally. Over 50 species of Enantiornithines have been named, but some...
and other Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
birds - as well as molecular (DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
and protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
) sequences allowed scientists to refine the classification. With new groups of neognath orders being verified, the taxonomic rank of the group needed to shift. In fact, most researchers have by now employed the unranked taxa of phylogenetic nomenclature
Phylogenetic nomenclature
Phylogenetic nomenclature or phylogenetic taxonomy is an alternative to rank-based nomenclature, applying definitions from cladistics . Its two defining features are the use of phylogenetic definitions of biological taxon names, and the lack of obligatory ranks...
.
The Neognathae are universally accepted to subdivide into two lineages - the "fowl" clade Galloanseres and the Neoaves (sometimes called "higher neognaths"). The subdivisions of the latter are still not well resolved, but several monophyletic lineages have been proposed, such as the Mirandornithes
Mirandornithes
Mirandornithes is a clade that consists of flamingos and grebes. The relationships of both groups have been problematic. Flamingos had been placed with numerous branches within Neognathae, such as ducks and storks. The grebes had been placed with the loons. However recent studies seem to confirm...
, Cypselomorphae
Cypselomorphae
Cypselomorphae is a clade of birds. It includes the living families and orders Caprimulgidae , Nyctibiidae , Apodiformes , as well as the Aegotheliformes whose distinctness was only recently realized...
or Metaves and Coronaves. While groups such as the former two - uniting a few closely related orders - are robustly supported, this cannot be said for the Metaves-Coronaves division for which there is no material evidence at present while the Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
record of Neognathae is at present utterly devoid of birds that would have to be present if these proposed clades were real.
Taxonomic note:
The ranks used here are rarely employed in the literature. The ultimate reason is a limitation in the Wikipedia taxobox code, which does not allow for an arbitrary number of "unranked" taxa to be displayed. As the taxa used here have all been validly described and neither the ICZN
International Code of Zoological Nomenclature
The International Code of Zoological Nomenclature is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals...
nor any other authority regulates their employment, the present ranking is as valid as any other - perhaps even more - and given the technical limitations the only system that can currently be used within the scope of Wikipedia. More commonly found is the old placement as a superorder - but such systematic treatments need to be viewed with caution, as they often do not even incorporate the Galloanserae - or as unranked clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
.
Systematics
The orders are arranged in a sequence that attempts to follow the modern view on neognath phylogeny. It differs from the widely used Clements taxonomyThe Clements Checklist of Birds of the World
The Clements Checklist of Birds of the World is a book by Jim Clements which presents a list of the bird species of the world.It is currently in its sixth edition , and is being published by Cornell University Press. Previous editions were published by the author's own imprint, Ibis Publishing. An...
as well as from the Sibley-Ahlquist taxonomy
Sibley-Ahlquist taxonomy
The Sibley-Ahlquist taxonomy is a bird taxonomy proposed by Charles Sibley and Jon Edward Ahlquist. It is based on DNA-DNA hybridization studies conducted in the late 1970s and throughout the 1980s....
, combining those elements from each that more modern research agrees with while updating those that are refuted. The result is at least a much better representation of the true evolutionary relationships of neognath orders. Most of the changes affect those "higher landbirds" that are sometimes united as near passerine
Near passerine
Near passerine or higher land-bird assemblage are terms often given to arboreal birds or those most often believed to be related to the true passerines due to ecological similarities; the group corresponds to some extent with the Anomalogonatae of Garrod All near passerines are land birds...
s.
- Superorder Galloanserae - fowl
- AnseriformesAnseriformesThe 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...
- waterfowl - GalliformesGalliformesGalliformes are an order of heavy-bodied ground-feeding domestic or game bird, containing turkey, grouse, chicken, New and Old World Quail, ptarmigan, partridge, pheasant, and the Cracidae. Common names are gamefowl or gamebirds, landfowl, gallinaceous birds or galliforms...
- wildfowl/landfowl
- Anseriformes
- Superorder Neoaves
- AccipitriformesAccipitriformesThe Accipitriformes is an order that has been proposed to include most of the diurnal birds of prey: hawks, eagles, vultures, and many others, about 225 species in all. For a long time, the majority view has been to include them with the falcons in the Falconiformes, but some authorities have...
- hawks, eagles, vultures - Aegotheliformes - owlet-nightjars
- ApodiformesApodiformesTraditionally, the bird order Apodiformes contained three living families: the swifts , the tree swifts , and the hummingbirds . In the Sibley-Ahlquist taxonomy, this order is raised to a superorder Apodimorphae in which hummingbirds are separated as a new order, Trochiliformes...
- swifts and hummingbirds - CaprimulgiformesCaprimulgiformesThe Caprimulgiformes is an order of birds that includes a number of birds with global distribution . They are generally insectivorous and nocturnal...
- nightjars and allies - CharadriiformesCharadriiformesCharadriiformes is a diverse order of small to medium-large birds. It includes about 350 species and has members in all parts of the world. Most Charadriiformes live near water and eat invertebrates or other small animals; however, some are pelagic , some occupy deserts and a few are found in thick...
- shorebirds/waders and allies - CiconiiformesCiconiiformesTraditionally, the order Ciconiiformes has included a variety of large, long-legged wading birds with large bills: storks, herons, egrets, ibises, spoonbills, and several others. Ciconiiformes are known from the Late Eocene...
- storks and allies (paraphyletic?) - Coliiformes - mousebirds
- ColumbiformesColumbiformesColumbiformes are an avian order that includes the very widespread and successful doves and pigeons, classified in the family Columbidae, and the extinct Dodo and the Rodrigues Solitaire, long classified as a second family Raphidae. 313 species, found worldwide, comprise the Columbiformes order....
- doves and pigeons - CoraciiformesCoraciiformesThe Coraciiformes are a group of usually colorful near passerine birds including the kingfishers, the Hoopoe, the bee-eaters, the rollers, and the hornbills...
- rollers and allies (paraphyletic?) - CuculiformesCuculiformesThe near passerine bird order Cuculiformes traditionally included three families as below:* Musophagidae - turacos and allies* Cuculidae - cuckoos, coucals, roadrunners and anis* Opisthocomidae - Hoatzin...
- cuckoos - FalconiformesFalconiformesThe order Falconiformes is a group of about 290 species of birds that comprises the diurnal birds of prey. Raptor classification is difficult and the order is treated in several ways.- Classification problems :...
- birds of prey - GaviiformesGaviiformesGaviiformes is an order of aquatic birds containing the loons or divers and their closest extinct relatives. Modern gaviiformes are found in many parts of North America and northern Eurasia , though prehistoric species were more widespread.-Classification and evolution:There are five living...
- loons/divers - GruiformesGruiformesThe Gruiformes are an order containing a considerable number of living and extinct bird families, with a widespread geographical diversity. Gruiform means "crane-like"....
- cranes and allies (paraphyletic?) - Musophagiformes - turacos
- Opisthocomiformes - Hoatzin
- Passeriformes - passerines/perching birds
- PelecaniformesPelecaniformesThe Pelecaniformes is a order of medium-sized and large waterbirds found worldwide. As traditionally—but erroneously—defined, they encompass all birds that have feet with all four toes webbed. Hence, they were formerly also known by such names as totipalmates or steganopodes...
- pelicans and allies (paraphyletic?) - Phaethontiformes - tropicbirds
- Phoenicopteriformes - flamingos
- PiciformesPiciformesNine families of largely arboreal birds make up the order Piciformes, the best-known of them being the Picidae, which includes the woodpeckers and close relatives...
- woodpeckers and allies - Podicipediformes - grebes
- ProcellariiformesProcellariiformesProcellariiformes is an order of seabirds that comprises four families: the albatrosses, petrels and shearwaters, storm petrels, and diving petrels...
- tubenoses - Psittaciformes - parrots and cockatoos
- Pteroclidiformes - sandgrouse
- Sphenisciformes - penguins
- Strigiformes - owls
- Trogoniformes - trogons
- Accipitriformes
Neognathia
Feduccia defined the clade Neognathia as birds are whose palatalPalate
The palate is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but, in most other tetrapods, the oral and nasal cavities are not truly separate. The palate is divided into two parts, the anterior...
mobility increased due to the following modifications (Feduccia 1980, 1996):
- Loss of the Basipterygoid articulation with the cranium.
- Development of a PterygoidPterygoidPterygoid can refer to:* Pterygoid processes of the sphenoid bone** The Lateral pterygoid plate by it* a muscle such as Lateral pterygoid muscle or Medial pterygoid muscle* a branch of the Mandibular nerve...
/PalatinePalatine boneThe palatine bone is a bone in many species of the animal kingdom, commonly termed the palatum .-Human anatomy:...
joint. - Reduction of the VomerVomerThe vomer is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones.-Biology:...
, such that it does not reach caudally to the pterygoidPterygoidPterygoid can refer to:* Pterygoid processes of the sphenoid bone** The Lateral pterygoid plate by it* a muscle such as Lateral pterygoid muscle or Medial pterygoid muscle* a branch of the Mandibular nerve...
, or is lost entirely.
See also
- Coronaves
- CypselomorphaeCypselomorphaeCypselomorphae is a clade of birds. It includes the living families and orders Caprimulgidae , Nyctibiidae , Apodiformes , as well as the Aegotheliformes whose distinctness was only recently realized...
- Metaves
- MirandornithesMirandornithesMirandornithes is a clade that consists of flamingos and grebes. The relationships of both groups have been problematic. Flamingos had been placed with numerous branches within Neognathae, such as ducks and storks. The grebes had been placed with the loons. However recent studies seem to confirm...
- Near passerineNear passerineNear passerine or higher land-bird assemblage are terms often given to arboreal birds or those most often believed to be related to the true passerines due to ecological similarities; the group corresponds to some extent with the Anomalogonatae of Garrod All near passerines are land birds...