64-634: Opisthocomidae is a family of birds , the only named family within the order Opisthocomiformes . The only living representative is the hoatzin ( Opisthocomus hoazin ) which lives in the Amazon and the Orinoco delta in South America. Several fossil species have been identified, including one from Africa and one from Europe. The phylogeny below is based on the work of Hughes & Baker 1999 and Mayr & De Pietri 2014. Traditionally classified among
128-401: A polyphyletic group consisting of all birds within the infraclass Palaeognathae that lack keels and cannot fly . They are mostly large, long-necked, and long-legged, the exception being the kiwi , which is also the only nocturnal extant ratite. The understanding of relationships within the paleognath clade has been in flux. Previously, all the flightless members had been assigned to
192-742: A better sense of smell. A third stage of bird evolution starting with Ornithothoraces (the "bird-chested" avialans) can be associated with the refining of aerodynamics and flight capabilities, and the loss or co-ossification of several skeletal features. Particularly significant are the development of an enlarged, keeled sternum and the alula , and the loss of grasping hands. † Anchiornis † Archaeopteryx † Xiaotingia † Rahonavis † Jeholornis † Jixiangornis † Balaur † Zhongjianornis † Sapeornis † Confuciusornithiformes † Protopteryx † Pengornis Ornithothoraces † Enantiornithes Ratite Tinamiformes Ratites ( / ˈ r æ t aɪ t s / ) are
256-455: A clade consisting of moas and tinamous, followed by the final two branches: a clade of emus plus cassowaries and one of elephant birds plus kiwis. Vicariant speciation based on the plate tectonic split-up of Gondwana followed by continental drift would predict that the deepest phylogenetic split would be between African and all other ratites, followed by a split between South American and Australo-Pacific ratites, roughly as observed. However,
320-473: A definition similar to "all theropods closer to birds than to Deinonychus ", with Troodon being sometimes added as a second external specifier in case it is closer to birds than to Deinonychus . Avialae is also occasionally defined as an apomorphy-based clade (that is, one based on physical characteristics). Jacques Gauthier , who named Avialae in 1986, re-defined it in 2001 as all dinosaurs that possessed feathered wings used in flapping flight , and
384-442: A group called Paraves . Some basal members of Deinonychosauria, such as Microraptor , have features which may have enabled them to glide or fly. The most basal deinonychosaurs were very small. This evidence raises the possibility that the ancestor of all paravians may have been arboreal , have been able to glide, or both. Unlike Archaeopteryx and the non-avialan feathered dinosaurs, who primarily ate meat, studies suggest that
448-634: A group of warm-blooded vertebrates constituting the class Aves ( Latin: [ˈaveːs] ), characterised by feathers , toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart , and a strong yet lightweight skeleton . Birds live worldwide and range in size from the 5.5 cm (2.2 in) bee hummingbird to the 2.8 m (9 ft 2 in) common ostrich . There are over 11,000 living species and they are split into 44 orders . More than half are passerine or "perching" birds. Birds have wings whose development varies according to species;
512-511: A highly developed sense of smell to find small insects and grubs in the soil. Kiwi are notable for laying eggs that are very large in relation to their body size. A kiwi egg may equal 15 to 20 percent of the body mass of a female kiwi. The smallest species of kiwi is the little spotted kiwi , at 0.9 to 1.9 kilograms (2.0–4.2 lb) and 35 to 45 centimetres (14–18 in). At least nine species of moa lived in New Zealand before
576-443: A keel). Without this to anchor their wing muscles, they could not have flown even if they had developed suitable wings. Ratites are a polyphyletic group; tinamous fall within them, and are the sister group of the extinct moa . This implies that flightlessness is a trait that evolved independently multiple times in different ratite lineages. Most parts of the former supercontinent Gondwana have ratites, or did have until
640-562: A light build, et cetera. The basal metabolic rate of flighted species is much higher than that of flightless terrestrial birds. But energetic efficiency can only help explain the loss of flight when the benefits of flying are not critical to survival. Research on flightless rails indicates the flightless condition evolved in the absence of predators. This shows flight to be generally necessary for survival and dispersal in birds. In apparent contradiction to this, many landmasses occupied by ratites are also inhabited by predatory mammals. However,
704-486: A quick escape decreases. Moreover, raptor species tend to become generalist predators on islands with low species richness, as opposed to specializing in the predation of birds. An increase in leg size compensates for a reduction in wing length in insular birds that have not lost flight by providing a longer lever to increase force generated during the thrust that initiates takeoff. Ratites in general have many physical characteristics in common, although many are not shared by
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#1732798670859768-406: A sister group, the order Crocodilia , contain the only living representatives of the reptile clade Archosauria . During the late 1990s, Aves was most commonly defined phylogenetically as all descendants of the most recent common ancestor of modern birds and Archaeopteryx lithographica . However, an earlier definition proposed by Jacques Gauthier gained wide currency in the 21st century, and
832-596: A ten-million-year-long window of opportunity for evolution of avian gigantism on continents may have existed following the extinction of the non-avian dinosaurs , in which ratites were able to fill vacant herbivorous niches before mammals attained large size. Some authorities, though, have been skeptical of the new findings and conclusions. Kiwi and tinamous are the only palaeognath lineages not to evolve gigantism, perhaps because of competitive exclusion by giant ratites already present on New Zealand and South America when they arrived or arose. The fact that New Zealand has been
896-717: A time, sometimes for years, and rarely for life. Other species have breeding systems that are polygynous (one male with many females) or, rarely, polyandrous (one female with many males). Birds produce offspring by laying eggs which are fertilised through sexual reproduction . They are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching. Many species of birds are economically important as food for human consumption and raw material in manufacturing, with domesticated and undomesticated birds being important sources of eggs, meat, and feathers. Songbirds , parrots, and other species are popular as pets. Guano (bird excrement)
960-504: A whole probably had an origin in the northern hemisphere. Early Cenozoic northern hemisphere paleognaths such as Lithornis , Pseudocrypturus , Paracathartes and Palaeotis appear to be the most basal members of the clade. The various ratite lineages were probably descended from flying ancestors that independently colonised South America and Africa from the north, probably initially in South America. From South America they could have traveled overland to Australia via Antarctica, (by
1024-490: Is a stunning, colourful bird from South America. The hoatzin is found in the rainforest of the Amazon. It has a long, permanently erected crest which gives the species a stunning silhouette. This gregarious species is often found in groups of more than 40 birds, and up to 100 birds during breeding season which occurs during rainfalls. The nest is a flat platform in bush or tree above water. The chicks are semi-precocial and leave
1088-426: Is an arboreal species and is folivorous, feeding on leaves, flowers and fruits of a small number of plant species. It has a large crop that uses bacteria to break down the leaves that it eats. The hoatzin is unique because it has bacteria in its crop that breaks down its food while it is still in the crop. This is a process called foregut fermentation . It rarely drinks because its diet includes water. The hoatzin
1152-540: Is called ornithology . Birds are feathered theropod dinosaurs and constitute the only known living dinosaurs . Likewise, birds are considered reptiles in the modern cladistic sense of the term, and their closest living relatives are the crocodilians . Birds are descendants of the primitive avialans (whose members include Archaeopteryx ) which first appeared during the Late Jurassic . According to recent estimates, modern birds ( Neornithes ) evolved in
1216-442: Is commonplace. Struthionidae (ostriches, 2 spp.) Rheidae (rheas, 2~3 spp.) † Dinornithiformes (moa) Tinamidae (tinamous, 46 spp.) † Aepyornithidae (elephant birds) Apterygidae (kiwi, 5 spp.) Casuariidae (cassowaries, 3 spp.) Dromaiidae (emus, 1 sp.) By 2014, a mitochondrial DNA phylogeny including fossil members placed ostriches on the basal branch, followed by rheas, then
1280-501: Is currently lacking. Ratite chicks tend to be more omnivorous or insectivorous ; similarities in adults end with feeding, as they all vary in diet and length of digestive tract, which is indicative of diet. Ostriches, with the longest tracts at 14 m (46 ft), are primarily herbivorous . Rheas' tracts are next longest at 8–9 m (26–30 ft), and they also have caeca . They are also mainly herbivores , concentrating on broad-leafed plants. However, they will eat insects if
1344-429: Is harvested for use as a fertiliser. Birds figure throughout human culture. About 120 to 130 species have become extinct due to human activity since the 17th century, and hundreds more before then. Human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them. Recreational birdwatching is an important part of the ecotourism industry. The first classification of birds
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#17327986708591408-503: Is not considered a direct ancestor of birds, though it is possibly closely related to the true ancestor. Over 40% of key traits found in modern birds evolved during the 60 million year transition from the earliest bird-line archosaurs to the first maniraptoromorphs , i.e. the first dinosaurs closer to living birds than to Tyrannosaurus rex . The loss of osteoderms otherwise common in archosaurs and acquisition of primitive feathers might have occurred early during this phase. After
1472-401: Is sedentary and widespread in suitable habitat. They are noisy birds, calling in unison, uttering large numbers of varied sounds. In addition to foregut fermentation , the hoatzin has a highly modified skeleton to accommodate its large crop, and in the young of this species, wing claws at the wrist joint which are used to climb among the branches of the nest tree. Bird Birds are
1536-516: Is synonymous to Avifilopluma. † Scansoriopterygidae † Eosinopteryx † Jinfengopteryx † Aurornis † Dromaeosauridae † Troodontidae Avialae Based on fossil and biological evidence, most scientists accept that birds are a specialised subgroup of theropod dinosaurs and, more specifically, members of Maniraptora , a group of theropods which includes dromaeosaurids and oviraptorosaurs , among others. As scientists have discovered more theropods closely related to birds,
1600-521: Is the largest living ratite. A large member of this species can be nearly 2.8 metres (9 ft 2 in) tall, weigh as much as 156 kilograms (344 lb), and can outrun a horse. Of the living species, the Australian emu is next in height, reaching up to 1.9 metres (6 ft 3 in) tall and about 50 kilograms (110 lb). Like the ostrich, it is a fast-running, powerful bird of the open plains and woodlands . Also native to Australia and
1664-535: Is used by many scientists including adherents to the PhyloCode . Gauthier defined Aves to include only the crown group of the set of modern birds. This was done by excluding most groups known only from fossils , and assigning them, instead, to the broader group Avialae, on the principle that a clade based on extant species should be limited to those extant species and their closest extinct relatives. Gauthier and de Queiroz identified four different definitions for
1728-463: The K–Pg extinction event created a window of time with large predators absent that may have allowed the ancestors of extant flightless ratites to evolve flightlessness. They subsequently underwent selection for large size. One hypothesis suggests that as predation pressure decreases on islands with low raptor species richness and no mammalian predators, the need for large, powerful flight muscles that make for
1792-722: The Late Cretaceous and diversified dramatically around the time of the Cretaceous–Paleogene extinction event 66 million years ago, which killed off the pterosaurs and all non- ornithuran dinosaurs. Many social species preserve knowledge across generations ( culture ). Birds are social, communicating with visual signals, calls, and songs , and participating in such behaviour as cooperative breeding and hunting, flocking , and mobbing of predators. The vast majority of bird species are socially (but not necessarily sexually) monogamous , usually for one breeding season at
1856-669: The Tiaojishan Formation of China, which has been dated to the late Jurassic period ( Oxfordian stage), about 160 million years ago. The avialan species from this time period include Anchiornis huxleyi , Xiaotingia zhengi , and Aurornis xui . The well-known probable early avialan, Archaeopteryx , dates from slightly later Jurassic rocks (about 155 million years old) from Germany . Many of these early avialans shared unusual anatomical features that may be ancestral to modern birds but were later lost during bird evolution. These features include enlarged claws on
1920-491: The 18th century, which led to hunting and sharp declines in populations. Ostrich farming grew out of this need, and humans harvested feathers, hides, eggs, and meat from the ostrich. Emu farming also became popular for similar reasons and for their emu oil . Rhea feathers are popular for dusters, and eggs and meat are used for chicken and pet feed in South America. Ratite hides are popular for leather products like shoes. The USDA's Food Safety and Inspection Service (FSIS) began
1984-464: The Middle Eocene ratites such as Palaeotis and Remiornis from Central Europe may imply that the "out-of-Gondwana" hypothesis is oversimplified. Molecular phylogenies of the ratites have generally placed ostriches in the basal position and among extant ratites, placed rheas in the second most basal position, with Australo-Pacific ratites splitting up last; they have also shown that both
Opisthocomidae - Misplaced Pages Continue
2048-425: The New Zealand kiwi. Additional support for the latter relationship was obtained from morphological analysis. The finding that tinamous nest within this group, originally based on twenty nuclear genes and corroborated by a study using forty novel nuclear loci makes 'ratites' polyphyletic rather than monophyletic, if we exclude the tinamous. Since tinamous are weak fliers, this raises interesting questions about
2112-582: The ancestors of ratites, were present and widespread in Gondwana during the Late Cretaceous. As the supercontinent fragmented due to plate tectonics , they were carried by plate movements to their current positions and evolved into the species present today. The earliest known ratite fossils date to the Paleocene epoch about 56 million years ago (e.g., Diogenornis , a possible early relative of
2176-428: The appearance of Maniraptoromorpha, the next 40 million years marked a continuous reduction of body size and the accumulation of neotenic (juvenile-like) characteristics. Hypercarnivory became increasingly less common while braincases enlarged and forelimbs became longer. The integument evolved into complex, pennaceous feathers . The oldest known paravian (and probably the earliest avialan) fossils come from
2240-406: The arrival of humans, ranging from turkey-sized to the giant moa Dinornis robustus with a height of 3.7 metres (12 ft 2 in) and weighing about 230 kilograms (510 lb). They became extinct by A.D. 1400 due to hunting by Māori settlers, who arrived around A.D. 1280. Aepyornis maximus , the "elephant bird" of Madagascar , was the heaviest bird ever known. Although shorter than
2304-509: The birds that descended from them. Despite being currently one of the most widely used, the crown-group definition of Aves has been criticised by some researchers. Lee and Spencer (1997) argued that, contrary to what Gauthier defended, this definition would not increase the stability of the clade and the exact content of Aves will always be uncertain because any defined clade (either crown or not) will have few synapomorphies distinguishing it from its closest relatives. Their alternative definition
2368-665: The earliest members of Aves, is removed from this group, becoming a non-avian dinosaur instead. These proposals have been adopted by many researchers in the field of palaeontology and bird evolution , though the exact definitions applied have been inconsistent. Avialae, initially proposed to replace the traditional fossil content of Aves, is often used synonymously with the vernacular term "bird" by these researchers. † Coelurus † Ornitholestes † Ornithomimosauria † Alvarezsauridae † Oviraptorosauria Paraves Most researchers define Avialae as branch-based clade, though definitions vary. Many authors have used
2432-425: The elephant bird–kiwi relation appears to require dispersal across oceans by flight, as apparently does the colonization of New Zealand by the moa and possibly the back-dispersal of tinamous to South America, if the latter occurred. The phylogeny as a whole suggests not only multiple independent origins of flightlessness, but also of gigantism (at least five times). Gigantism in birds tends to be insular ; however,
2496-454: The evolution of flightlessness in this group. The branching of the tinamous within the ratite radiation suggests flightlessness evolved independently among ratites at least three times. More recent evidence suggests this happened at least six times, or once in each major ratite lineage. Re-evolution of flight in the tinamous would be an alternative explanation, but such a development is without precedent in avian history, while loss of flight
2560-429: The exception with extended monogamous reproductive strategies where either the male alone or both sexes incubate a single egg. Unlike most birds, male ratites have a phallus that is inserted into the female's cloaca during copulation . Ratites and humans have had a long relationship starting with the use of the egg for water containers, jewelry, or other art medium. Male ostrich feathers were popular for hats during
2624-738: The fairly recent past. So did Europe in the Paleocene and Eocene , from where the first flightless paleognaths are known. Ostriches were present in Asia as recently as the Holocene , although the genus is thought to have originated in Africa. However, the ostrich order may have evolved in Eurasia. A recent study posits a Laurasian origin for the clade. Geranoidids , which may have been ratites, existed in North America. The African ostrich
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2688-651: The family Tinamidae , or tinamous. First, the breast muscles are underdeveloped. They do not have keeled sterna . Their wishbones ( furculae ) are almost absent. They have simplified wing skeletons and musculature. Their legs are stronger and do not have air chambers, except the femurs . Their tail and flight feathers have retrogressed or have become decorative plumes. They have no feather vanes, which means they do not need to oil their feathers, hence they have no preen glands . They have no separation of pterylae (feathered areas) and apteria (non-feathered areas), and finally, they have palaeognathous palates . Ostriches have
2752-451: The first avialans were omnivores . The Late Jurassic Archaeopteryx is well known as one of the first transitional fossils to be found, and it provided support for the theory of evolution in the late 19th century. Archaeopteryx was the first fossil to display both clearly traditional reptilian characteristics—teeth, clawed fingers, and a long, lizard-like tail—as well as wings with flight feathers similar to those of modern birds. It
2816-491: The fowl-like birds ( Galliformes ), recent studies have favored Opisthocomidae's placement within the Neoaves . † Namibiavis † Protoazin † Hoazinavis Opisthocomus The only living representative is the hoatzin ( Opisthocomus hoazin ), which lives in the Amazon and the Orinoco delta in South America. Several fossil species have been identified, including one from Africa and one from Europe. The hoatzin
2880-866: The greatest dimorphism , rheas show some dichromatism during the breeding season. Emus, cassowaries, and kiwis show some dimorphism, predominantly in size. While the ratites share a lot of similarities, they also have major differences. Ostriches have only two toes, with one being much larger than the other. Cassowaries have developed long inner toenails, used defensively. Ostriches and rheas have prominent wings; although they do not use them to fly, they do use them in courtship and predator distraction. Without exception, ratite chicks are capable of swimming and even diving. On an allometric basis, paleognaths have generally smaller brains than neognaths . Kiwis are exceptions to this trend, and possess proportionally larger brains comparable to those of parrots and songbirds , though evidence for similar advanced cognitive skills
2944-739: The groups as families in the order Struthioniformes , while the other supposes that the lineages evolved mostly independently and thus elevates the families to order rank ( Rheiformes , Casuariformes etc.). The longstanding story of ratite evolution was that they share a common flightless ancestor that lived in Gondwana , whose descendants were isolated from each other by continental drift , which carried them to their present locations. Supporting this idea, some studies based on morphology, immunology and DNA sequencing reported that ratites are monophyletic . Cracraft's 1974 biogeographic vicariance hypothesis suggested that ancestral flightless paleognaths,
3008-505: The incubating duties with others. Ostriches, and great spotted kiwis, are the only ratites where the female incubates; they share the duties, with the males incubating at night. Cassowaries and emu are polyandrous, with males incubating eggs and rearing chicks with no obvious contribution from females. Ostriches and rheas are polygynous with each male courting several females. Male rheas are responsible for building nests and incubating while ostrich males incubate only at night. Kiwis stand out as
3072-411: The islands to the north are the three species of cassowary . Shorter than an emu, but heavier and solidly built, cassowaries prefer thickly vegetated tropical forest. They can be dangerous when surprised or cornered because of their razor-sharp talons . In New Guinea , cassowary eggs are brought back to villages and the chicks raised for eating as a much-prized delicacy, despite (or perhaps because of)
3136-622: The latter groups are monophyletic. Early mitochondrial genetic studies that failed to make ostriches basal were apparently compromised by the combination of rapid early radiation of the group and long terminal branches. A morphological analysis that created a basal New Zealand clade has not been corroborated by molecular studies. A 2008 study of nuclear genes shows ostriches branching first, followed by rheas and tinamous, then kiwi splitting from emus and cassowaries. In more recent studies, moas and tinamous were shown to be sister groups , and elephant birds were shown to be most closely related to
3200-570: The latter's case. Some extinct ratites might have had odder lifestyles, such as the narrow-billed Diogenornis and Palaeotis , compared to the shorebird-like lithornithids , and could imply similar animalivorous diets. Ratites are different from the flying birds in that they needed to adapt or evolve certain features to protect their young. First and foremost is the thickness of the shells of their eggs. Their young are hatched more developed than most and they can run or walk soon thereafter. Also, most ratites have communal nests, where they share
3264-477: The nest at about two to three weeks of age. The adults feed them with semi-digested slimy mass from their crops, and the young are fed during the first four or five months of their life. The young nestlings can jump out into the water, and swim with wings and feet, in order to escape predators at nest. Hoatzin embryos are known to develop very quickly compared to other birds. The hoatzin lives in tropical forested wetlands of 200 to 500 meters elevation. The hoatzin
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#17327986708593328-523: The only known groups without wings are the extinct moa and elephant birds . Wings, which are modified forelimbs , gave birds the ability to fly, although further evolution has led to the loss of flight in some birds , including ratites , penguins , and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds , have further evolved for swimming. The study of birds
3392-512: The only land mass to recently support two major lineages of flightless ratites may reflect the near total absence of native mammals, which allowed kiwi to occupy a mammal-like nocturnal niche . However, various other landmasses such as South America and Europe have supported multiple lineages of flightless ratites that evolved independently, undermining this competitive exclusion hypothesis. Most recently, studies on genetic and morphological divergence and fossil distribution show that paleognaths as
3456-450: The opportunity arises. Emus have tracts of 7 m (23 ft) length, and have a more omnivorous diet, including insects and other small animals. Cassowaries have next to the shortest tracts at 4 m (13 ft). Finally, kiwi have the shortest tracts and eat earthworms, insects, and other similar creatures. Moas and elephant birds were the largest native herbivores in their faunas, far larger than contemporary herbivorous mammals in
3520-492: The order Struthioniformes , which is more recently regarded as containing only the ostrich . The modern bird superorder Palaeognathae consists of ratites and the flighted Neotropic tinamous (compare to Neognathae ). Unlike other flightless birds, the ratites have no keel on their sternum — hence the name, from the Latin ratis (' raft ', a vessel which has no keel — in contradistinction to extant flighted birds with
3584-402: The outermost half) can be seen in the evolution of maniraptoromorphs, and this process culminated in the appearance of the pygostyle , an ossification of fused tail vertebrae. In the late Cretaceous, about 100 million years ago, the ancestors of all modern birds evolved a more open pelvis, allowing them to lay larger eggs compared to body size. Around 95 million years ago, they evolved
3648-536: The previously clear distinction between non-birds and birds has become blurred. By the 2000s, discoveries in the Liaoning Province of northeast China, which demonstrated many small theropod feathered dinosaurs , contributed to this ambiguity. The consensus view in contemporary palaeontology is that the flying theropods, or avialans , are the closest relatives of the deinonychosaurs , which include dromaeosaurids and troodontids . Together, these form
3712-524: The rhea). However, more primitive paleognaths are known from several million years earlier, and the classification and membership of the Ratitae itself is uncertain. Some of the earliest ratites occur in Europe. Recent analyses of genetic variation between the ratites do not support this simple picture. The ratites may have diverged from one another too recently to share a common Gondwanan ancestor. Also,
3776-577: The risk they pose to life and limb. They reach up to 1.8 metres (5 ft 11 in) tall and weigh as much as 85 kilograms (187 lb) South America has two species of rhea , large fast-running birds of the Pampas . The larger American rhea grows to about 1.4 metres (4 ft 7 in) tall and usually weighs 15 to 40 kilograms (33–88 lb). The smallest ratites are the five species of kiwi from New Zealand. Kiwi are chicken -sized, shy, and nocturnal . They nest in deep burrows and use
3840-452: The same biological name "Aves", which is a problem. The authors proposed to reserve the term Aves only for the crown group consisting of the last common ancestor of all living birds and all of its descendants, which corresponds to meaning number 4 below. They assigned other names to the other groups. Lizards & snakes Turtles Crocodiles Birds Under the fourth definition Archaeopteryx , traditionally considered one of
3904-460: The same route marsupials are thought to have used to reach Australia ) and then reached New Zealand and Madagascar via "sweepstakes" dispersals (rare low probability dispersal methods, such as long distance rafting) across the oceans. Gigantism would have evolved subsequent to trans-oceanic dispersals. Loss of flight allows birds to eliminate the costs of maintaining various flight-enabling adaptations like high pectoral muscle mass, hollow bones and
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#17327986708593968-551: The second toe which may have been held clear of the ground in life, and long feathers or "hind wings" covering the hind limbs and feet, which may have been used in aerial maneuvering. Avialans diversified into a wide variety of forms during the Cretaceous period. Many groups retained primitive characteristics , such as clawed wings and teeth, though the latter were lost independently in a number of avialan groups, including modern birds (Aves). Increasingly stiff tails (especially
4032-500: The tallest moa, a large A. maximus could weigh over 400 kilograms (880 lb) and stand up to 3 metres (9 ft 10 in) tall. Accompanying it were three other species of Aepyornis as well as three species of the smaller genus Mullerornis . All these species went into decline following the arrival of humans on Madagascar around 2,000 years ago, and were gone by the 17th or 18th century if not earlier. There are two taxonomic approaches to ratite classification: one combines
4096-466: Was developed by Francis Willughby and John Ray in their 1676 volume Ornithologiae . Carl Linnaeus modified that work in 1758 to devise the taxonomic classification system currently in use. Birds are categorised as the biological class Aves in Linnaean taxonomy . Phylogenetic taxonomy places Aves in the clade Theropoda as an infraclass or a subclass, more recently a subclass. Aves and
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