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Neornithes

(Subclass)

Overview

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Modern birds (subclass Neornithes) are the most recent common ancestor of all living (class Aves) and all its descendants.

Modern birds are characterised by feathers, a beak with no teeth (ancient birds had teeth), the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. All birds have forelimbs modified as wings and most can fly, with some exceptions including ratites, penguins, and a number of diverse endemic island species. Birds also have unique digestive and respiratory systems that are highly adapted for flight. Some birds, especially corvids and parrots, are among the most intelligent animal species; a number of bird species have been observed manufacturing and using tools, and many social species exhibit cultural transmission of knowledge across generations.

Many species of modern bird undertake long distance annual migrations, and many more perform shorter irregular movements. Birds are social; they communicate using visual signals and through calls and songs, and participate in social behaviours including cooperative breeding and hunting, flocking, and mobbing of predators. The vast majority of bird species are socially monogamous, usually for one breeding season at a time, sometimes for years, but rarely for life. Engagement in extra-pair copulations is common in some species; other species have breeding systems that are polygynous ("many females") or, rarely, polyandrous ("many males"). Eggs are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching.

Taxonomy

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Modern birds are divided into two superorders; the Palaeognathae (tinamous and flightless ratites like ostri ches), and the wildly diverse Neognathae, containing all other birds. Depending on the taxonomic viewpoint, the number of species cited varies anywhere from 8,800 to 10,200 known living bird species in the world. It is generally agreed that the Neornithes evolved in the Cretaceous Period and that the split between the Palaeognathae and Neognathae, and then the split between Galloanserae (fowl) and the other Neognathae, occurred before the Cretaceous-Tertiary (K-T) extinction event, but there are different opinions about whether the radiation of the remaining neognathes occurred before or after the extinction of the other dinosaurs.[2] This disagreement is in part caused by a divergence in the evidence, with molecular dating suggesting a Cretaceous radiation and fossil evidence supporting a Tertiary radiation. Attempts made to reconcile the molecular and fossil evidence have proved controversial.[2][3]

The classification of modern birds is a contentious issue. Sibley & Ahlquist's Phylogeny and Classification of Birds (1990) is a landmark work on the classification of birds, although frequently debated and constantly revised. A preponderance of evidence seems to suggest that the modern bird orders constitute accurate taxa. However, scientists are not in agreement as to the relationships between the orders; evidence from modern bird anatomy, fossils and DNA have all been brought to bear on the problem but no strong consensus has emerged. More recently, new fossil and molecular evidence is providing an increasingly clear picture of the evolution of modern bird orders. See also: Sibley-Ahlquist taxonomy and dinosaur classification.

Classification

Cladogram showing the most recent classification of Neoaves, based several phylogenetic studies.

This is a list of the taxonomic orders in the subclass Neornithes, or modern birds. The list of birds gives a more detailed summary of these, including families.

Subclass Neornithes

Note: This list is mostly based on the traditional classification (the so-called Clements order) - with the addition of the commonly accepted Galloanserae and Neoaves clades. A radically different classification based on molecular data has been developed (the so-called Sibley-Monroe classification or Sibley-Ahlquist taxonomy). Some of the proposals of the Sibley-Ahlquist taxonomy has influenced taxonomic thinking considerably, with the Galloanserae proving well-supported by recent molecular, fossil and anatomical evidence.[2] With increasingly good evidence, it has become possible to test some major proposals of the Sibley-Ahlquist taxonomy, with favorable results (see for example Charadriiformes, Gruiformes or Caprimulgiformes). However, many proposals of the Sibley-Ahlquist taxonomy are now discarded by most scientists, such as the lumping of many unrelated orders into a greatly enlarged Ciconiiformes.

Phylogeny

Sketch of a Neornithes tree in and around K-T

Basal divergences of modern birds based on the Sibley-Ahlquist taxonomy.

Photos

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Taxonomy

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The Subclass Neornithes is a member of the Class Aves. Here is the complete "parentage" of Neornithes:

The Subclass Neornithes is further organized into finer groupings including:

Orders

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Aepyornithiformes

[more]

Anseriformes

The order Anseriformes contains about 150 living of birds in three extant families: the Anhimidae (the screamers), Anseranatidae (the Magpie-goose), and the Anatidae, which includes over 140 species of waterfowl, among them the ducks, geese, and swans. [more]

Apodiformes

Traditionally, the order Apodiformes contained three living families: the swifts, Apodidae, the tree swifts, Hemiprocnidae, and the hummingbirds, Trochilidae. In the Sibley-Ahlquist taxonomy, this order is raised to a superorder Apodimorphae in which hummingbirds are separated as a new order, Trochiliformes, but this has been refuted by subsequent research. With nearly 450 species identified to date, they are the most diverse order of birds after the passerines. [more]

Bucerotiformes

Hornbills (Bucerotidae) are a of bird found in tropical and sub-tropical Africa and Asia. They are characterized by a long, down-curved bill which is frequently brightly-colored and sometimes has a casque on the upper mandible. Both the common English and the scientific name of the family refer to the shape of the bill, "buceros" being "cow horn" in Greek. In addition, they possess a two-lobed kidney. Hornbills are the only birds in which the first two neck vertebrae (the axis and atlas) are fused together; this probably provides a more stable platform for carrying the bill. The family is omnivorous, feeding on fruit and small animals. They are monogamous breeders nesting in natural cavities in trees and sometimes cliffs. A number of species of hornbill are threatened with extinction, mostly insular species with small ranges. [more]

Charadriiformes

Charadriiformes is a diverse order of small to medium-large . 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 (sea birds), some occupy deserts and a few are found in thick forest. [more]

Ciconiiformes

Traditionally, the 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. At present the only family retained in the order is the storks, Ciconiidae. [more]

Coliiformes

The mousebirds are a small group of (possibly ) birds which have no real close affinities to other groups, though they and the parrots and cockatoos (Psittaciformes) may be closer to each other than to other birds. The mousebirds are therefore given order status as Coliiformes. This group is confined to sub-Saharan Africa, and is the only bird order confined entirely to that continent. They had a wider range in prehistoric times and apparently evolved in Europe. [more]

Columbiformes

The order Columbiformes 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. Like many birds, all Columbiformes are monogamous. Unlike most other birds, however, they are capable of drinking by sucking up water, without needing to tilt the head back. [more]

Coraciiformes

The Coraciiformes are a group of usually colorful birds including the kingfishers, the Hoopoe, the bee-eaters, the rollers, and the hornbills. They generally have syndactyly, with three forward-pointing toes (and toes 3 & 4 fused at their base), though in many kingfishers one of these is missing. [more]

Craciformes

Galliformes are an of birds containing turkeys, grouse, chickens, quails, and pheasants. More than 250 living species are found worldwide. Common names are gamefowl or gamebirds, landfowl, gallinaceous birds or galliforms. "Wildfowl" or just "fowl" are also often used for Galliformes, but usually these terms also refer to waterfowl, and occasionally to other commonly-hunted birds. [more]

Cuculiformes

The bird order Cuculiformes traditionally included three families as below: [more]

Diatrymiformes

[more]

Dinornithiformes

[more]

Galbuliformes

An of birds comprising the jacamar and puffbird families, Galbulidae and Bucconidae. there are 51 species ranging from Mexico to tropical South America. [more]

Galliformes

Galliformes are an of birds containing turkeys, grouse, chickens, quails, and pheasants. More than 250 living species are found worldwide. Common names are gamefowl or gamebirds, landfowl, gallinaceous birds or galliforms. "Wildfowl" or just "fowl" are also often used for Galliformes, but usually these terms also refer to waterfowl, and occasionally to other commonly-hunted birds. [more]

Gruiformes

The polyphyletic Gruiformes contains a considerable number of living and extinct bird families with little in common. They are morphologically diverse and geographically widespread. Gruiform means "crane-like." [more]

Lithornithiformes

[more]

Musophagiformes

The turacos make up the family Musophagidae (literally "banana-eaters"), which includes plantain-eaters and go-away-birds. In southern Africa both turacos and go-away-birds are commonly known as louries. They are semi-zygodactylous - the fourth (outer) toe can be switched back and forth. The second and third toes, which always point forward, are conjoined in some species. Musophagids often have prominent crests and long tails; the turacos are noted for peculiar and quite unique pigments giving them their bright green and red feathers. [more]

Palaeocursornithiformes

[more]

Passeriformes

A passerine is a of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: it is roughly twice as diverse as the largest of the mammal orders, the Rodentia. [more]

Piciformes

Six of largely arboreal birds make up the order Piciformes, the best-known of them being the Picidae, which includes the woodpeckers and close relatives. The Piciformes contain about 67 living genera with a little over 400 species, of which the Picidae (woodpeckers and relatives) make up about half. [more]

Procellariiformes

Procellariiformes is an order of that comprises four families: the albatrosses, procellariids, storm-petrels and diving petrels. Formerly called Tubinares and still called tubenoses in English, they are often referred to collectively as the petrels, a term that has been applied to all Procellariiformes or more commonly all the families except the albatrosses. They are almost exclusively pelagic (feeding in the open ocean). They have a cosmopolitan distribution across the world's oceans, with the highest diversity being around New Zealand. [more]

Psittaciformes

Parrots, also known as psittacines , are of the roughly 372 species in 86 genera that make up the order Psittaciformes, found in most warm and tropical regions. The order is subdivded in three families: the Psittacidae (true parrots), the Cacatuidae (cockatoos) and the Nestoridae. Parrots have a pan-tropical distribution with several species inhabiting the temperate Southern Hemisphere as well. The greatest diversity of parrots is found in South America and Australasia. [more]

Strigiformes

The Strigiformes (Owls) are an of birds of prey, comprising 200 extant species. Most are solitary, and nocturnal, with some exceptions (e.g. the Burrowing Owl). Owls mostly hunt small mammals, insects, and other birds, though a few species specialize in hunting fish. They are found in all regions of the Earth except Antarctica, most of Greenland, and some remote islands. Though owls are typically solitary, the literary collective noun for a group of owls is a parliament. [more]

Struthioniformes

[more]

Tinamiformes

The tinamous are a comprising 47 species of birds found in Central and South America. One of the most ancient living groups of bird, they are related to the ratites. Generally ground dwelling, they are found in a range of habitats. [more]

Trochiliformes

Hummingbirds are in the family Trochilidae, and are native to the Americas. They are among the smallest of birds, and include the smallest extant bird species, the Bee Hummingbirds. They can hover in mid-air by rapidly flapping their wings 12-90 times per second (depending on the species). They can also fly backwards, and are the only group of birds able to do so. Their English name derives from the characteristic hum made by their rapid wing beats. They can fly at speeds exceeding 15 m/s (54 km/h; 34 mph). [more]

Trogoniformes

The trogons and quetzals are in the order Trogoniformes which contains only one family, the Trogonidae. The family contains 39 species in eight genera. The fossil record of the trogons dates back 49 million years to the mid-Eocene. They might constitute a member of the basal radiation of the order Coraciiformes. The word "trogon" is Greek for "nibbling" and refers to the fact that these birds gnaw holes in trees to make their nests. [more]

Turniciformes

The buttonquails or hemipodes are a small family of which resemble, but are unrelated to, the true quails. They inhabit warm grasslands in Asia, Africa, and Australia. [more]

Upupiformes

The Hoopoe , Upupa epops, is a colorful bird that is found across , notable for its distinctive 'crown' of feathers. It is the only extant species in the family Upupidae. One insular species, the Giant Hoopoe is extinct, and the Madgascar subspecies of the Hoopoe is sometimes elevated to a full species. [more]

At least 80 species and subspecies belong to the Order Upupiformes.

More info about the Order Upupiformes may be found here.

References

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Footnotes

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  1. ^ System Naturae 2000
  2. ^ a b c Ericson PGP, Anderson CL, Britton T, Elzanowski A, Johansson US, Kallersjo M, Ohlson JI, Parsons TJ, Zuccon D, Mayr G (22 December 2006). "Diversification of Neoaves: integration of molecular sequence data and fossils". Biol Lett 2 (4): 543-547. doi:10.1098/rsbl.2006.0523 . PMID 17148284. 
  3. ^ Brown J, Payne B, Mindell D (27 June 2007). "Nuclear DNA does not reconcile 'rocks' and 'clocks' in Neoaves: a comment on Ericson et al.". Biol Lett 3 (3): 1-3. doi:10.1098/rsbl.2006.0611. PMID 17389215. 
  4. ^ Chiappe, Luis M. (2007). Glorified Dinosaurs: The Origin and Early Evolution of Birds. Sydney: University of New South Wales Press. ISBN 978-0-86840-413-4. 

Sources

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Last Revised: September 22, 2009
2009/09/22 06:56:02