Dinornis Temporal range: Late Pleistocene-Holocene | |
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D. novaezealandiae, Natural History Museum of London | |
Extinct (c. 1500) | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Infraclass: | Palaeognathae |
Order: | † Dinornithiformes |
Family: | † Dinornithidae |
Genus: | † Dinornis Owen, 1843 [1] |
Species | |
D. novaezealandiae North Island giant moa Contents | |
Synonyms | |
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The giant moa (Dinornis) is an extinct genus of birds belonging to the moa family. As with other moa, it was a member of the order Dinornithiformes. It was endemic to New Zealand. Two species of Dinornis are considered valid, the North Island giant moa (Dinornis novaezealandiae) and the South Island giant moa (Dinornis robustus). In addition, two further species (new lineage A and lineage B) have been suggested based on distinct DNA lineages. [2]
Dinornis may have been the tallest bird that ever lived, with the females of the largest species standing 3.6 m (12 ft) tall, [3] and one of the most massive, weighing 230–240 kg (510–530 lb) [4] or 278 kg (613 lb) [5] in various estimates. Feather remains are reddish brown and hair-like, and apparently covered most of the body except the lower legs and most of the head (plus a small portion of the neck below the head). While no feathers have been found from moa chicks, it is likely that they were speckled or striped to camouflage them from Haast's Eagles. [6]
The feet were large and powerful, and could probably deliver a powerful kick if threatened. [6] The birds had long, strong necks and broad sharp beaks that would have allowed them to eat vegetation from subalpine herbs through to tree branches. [6] In relation to its body, the head was small, with a pointed, short, flat and somewhat curved beak.
The North Island giant moa tended to be larger than the South Island giant moa. [6]
The cladogram below follows a 2009 analysis by Bunce et al.: [7]
Dinornithiformes |
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Dinornis were very adaptable and were present in a wide range of habitats from coastal to alpine. [6] It is possible that individual moa would have moved from environment to environment with the changing seasons.
It has been long suspected that several species of moa constituted males and females, respectively. This has been confirmed by analysis for sex-specific genetic markers of DNA extracted from bone material. [8] For example, prior to 2003 there were three species of Dinornis recognised: South Island giant moa (D. robustus ), North Island giant moa (D. novaezealandiae) and slender moa (D. struthioides). However, DNA showed that all D. struthioides were in fact males, and all D. robustus were females. Therefore, the three species of Dinornis were reclassified as two species, one each formerly occurring in New Zealand's North Island (D. novaezealandiae) and South Island (D. robustus ); [8] [7] robustus however, comprises three distinct genetic lineages and may eventually be classified as many species. Dinornis seems to have had the most pronounced sexual dimorphism of all moa, with females being up to twice as tall and three times as heavy as males. [6]
While it is impossible to know exactly how Dinornis reproduced and raised young, assumptions can be made from extant ratites. [6] The larger females may have competed to mate with the most desirable males who themselves were likely to have been extremely territorial. Eggs may have been laid in communal nests in sand dunes, or by individual birds in sheltered environments such as hollow trees or by rocks. The female would have had little to do with the eggs once they had been laid while the male would have incubated the egg for up to three months before it hatched.
Dinornis eggs were enormous, as large as a rugby ball, and around 80 times the volume of a chicken's egg. [6] However, despite their size, Dinornis eggs were extremely thin, with D. novaezealandiae's eggshells being around 1.06 millimeters (0.04 inches) thick and D. robustus' eggshells being 1.4 millimeters (0.06 inches) thick. As such, Dinornis eggs have been estimated to be the 'most fragile of all avian eggs measured to date'. [9]
It is possible that such fragile eggs resulted in the male moa adapting to become smaller in size than the females to reduce the risk of crushing the eggs. However, it is possible that the male moa would curl themselves around the eggs rather than sitting on them directly. [6] Given the size of the eggs, and the incubation period, as soon as giant moa chicks hatched they would have been able to see, run and feed themselves. [6]
Prior to the arrival of humans, the giant moa had an ecologically stable population in New Zealand for at least 40,000 years. [10] The giant moa, along with other moa genera, were wiped out by Polynesian settlers, [10] who hunted it for food. All taxa in this genus were extinct by 1500 in New Zealand. It is generally accepted that the Māori still hunted them at the beginning of the fifteenth century, although some models suggest extinction had already taken place by the middle of the 14th century. [11] Although some birds became extinct due to farming, for which the forests were cut and burned down and the ground was turned into arable land, the giant moa had been extinct for 300 years prior to the arrival of European settlers. [12]
Moa are an extinct group of flightless birds formerly endemic to New Zealand. During the Late Pleistocene-Holocene, there were nine species. The two largest species, Dinornis robustus and Dinornis novaezelandiae, reached about 3.6 metres (12 ft) in height with neck outstretched, and weighed about 230 kilograms (510 lb) while the smallest, the bush moa, was around the size of a turkey. Estimates of the moa population when Polynesians settled New Zealand circa 1300 vary between 58,000 and approximately 2.5 million.
Haast's eagle is an extinct species of eagle that once lived in the South Island of New Zealand, commonly accepted to be the pouakai of Māori legend. It was the largest eagle known to have existed, with an estimated weight of 15 kilograms (33 lb), compared to the 9 kg (20 lb) harpy eagle. Its massive size is explained as an evolutionary response to the size of its prey, the flightless moa, the largest of which could weigh 230 kg (510 lb). Haast's eagle became extinct around 1400, following the arrival of the Māori, who outcompeted it for its moa prey.
A ratite is any of a diverse group of flightless, large, long-necked, and long-legged birds of the infraclass Palaeognathae. Kiwi, the exception, are much smaller and shorter-legged and are the only nocturnal extant ratites.
In terrestrial zoology, the megafauna comprises the large or giant animals of an area, habitat, or geological period, extinct and/or extant. The most common thresholds used are weight over 46 kilograms (100 lb) or over a tonne, 1,000 kilograms (2,205 lb). The first of these include many species not popularly thought of as overly large, and being the only few large animals left in a given range/area, such as white-tailed deer, Thomson's gazelle, and red kangaroo. In practice, the most common usage encountered in academic and popular writing describes land mammals roughly larger than a human that are not (solely) domesticated. The term is especially associated with the Pleistocene megafauna – the land animals often larger than their extant counterparts that are considered archetypical of the last ice age, such as mammoths, the majority of which in northern Eurasia, the Americas and Australia became extinct within the last forty thousand years. Among living animals, the term megafauna is most commonly used for the largest extant terrestrial mammals, which includes elephants, giraffes, hippopotamuses, rhinoceroses, and large bovines. Of these five categories of large herbivores, only bovines are presently found outside of Africa and southern Asia, but all the others were formerly more wide-ranging, with their ranges and populations continually shrinking and decreasing over time. Wild equines are another example of megafauna, but their current ranges are largely restricted to the old world, specifically Africa and Asia. Megafaunal species may be categorized according to their dietary type: megaherbivores, megacarnivores, and, more rarely, megaomnivores. The megafauna is also categorized by the class of animals that it belongs to, which are mammals, birds, reptiles, amphibians, fish, and invertebrates.
Elephant birds are extinct flightless birds belonging to the order Aepyornithiformes that were native to the island of Madagascar. They are thought to have become extinct by around 1260 CE, probably as a result of human activity. Elephant birds comprised three species, one in the genus Mullerornis, and two in Aepyornis.Aepyornis maximus is possibly the largest bird to have ever lived, with their eggs being the largest known for any amniote. Elephant birds are palaeognaths, and their closest living relatives are kiwi, suggesting that ratites did not diversify by vicariance during the breakup of Gondwana but instead convergently evolved flightlessness from ancestors that dispersed more recently by flying.
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 in general, is the ostrich.
The upland moa is an extinct species of moa that was endemic to New Zealand. It is a ratite, a grouping of flightless birds with no keel on the sternum. It was the last moa species to become extinct, vanishing in 1445 CE, and was predominantly found in alpine and sub-alpine environments.
Palaeognathae is a infraclass of birds, called paleognaths or palaeognaths, within the class Aves of the clade Archosauria. 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 47 species of tinamous, five of kiwis (Apteryx), three of cassowaries (Casuarius), one of emus (Dromaius), two of rheas (Rhea) and two of ostriches (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 eastern moa is an extinct species of moa that was endemic to New Zealand.
Pachyornis is an extinct genus of ratites from New Zealand which belonged to the moa family. Like all ratites it was a member of the order Struthioniformes. The Struthioniformes are flightless birds with a sternum without a keel. They also have a distinctive palate. This genus contains three species, and are part of the Anomalopteryginae or lesser moa subfamily. Pachyornis moa were the stoutest and most heavy-legged genus of the family, the most notable species being Pachyornis elephantopus - the heavy-footed moa. They were generally similar to the eastern moa or the broad-billed moa of the genus Euryapteryx, but differed in having a pointed bill and being more heavyset in general. At least one species is assumed to have had a crest of long feathers on its head. The species became rapidly extinct following human colonization of New Zealand, with the possible exception of P. australis, which may have already been extinct by then - although the most recent moa skeleton ever described is a partial skeleton of this species, radiocarbon dated to between 1396 and 1442.
The crested moa is an extinct species of moa. It is one of the 9 known species of moa to have existed.
The heavy-footed moa is a species of moa from the lesser moa family. The heavy-footed moa was widespread only in the South Island of New Zealand, and its habitat was the lowlands. The moa were ratites, flightless birds with a sternum without a keel. They also have a distinctive palate. The origin of these birds is becoming clearer as it is now believed that early ancestors of these birds were able to fly and flew to the southern areas in which they have been found.
The North Island giant moa is an extinct moa in the genus Dinornis. Even though it might have walked with a lowered posture, standing upright, it would have been the tallest bird ever to exist, with a height estimated up to 3.6 metres.
The South Island giant moa is an extinct species of moa in the genus Dinornis. It was the tallest-known bird species to walk the Earth, exceeded in weight only by the heavier but shorter elephant bird of Madagascar.
The broad-billed moa, stout-legged moa or coastal moa is an extinct species of moa that was endemic to New Zealand.
Notopalaeognathae is a clade that contains the order Rheiformes (rheas), the clade Novaeratitae, and the clade Dinocrypturi. The exact relationships of this group, including its recently extinct members, have only recently been uncovered. The two lineages endemic to New Zealand, the kiwis and the extinct moas, are not each other's closest relatives: the moas are most closely related to the Neotropical tinamous, and the kiwis are sister to the extinct elephant birds of Madagascar, with kiwis and elephant birds together sister to the cassowaries and emu of New Guinea and Australia. The South American rheas are either sister to all other notopalaeognaths or sister to Novaeratitae. The sister group to Notopalaeognathae is Struthionidae.
This article records new taxa of fossil archosaurs of every kind that are scheduled described during the year 2014, as well as other significant discoveries and events related to paleontology of archosaurs that are scheduled to occur in the year 2014.
This article includes a list of general references, but it lacks sufficient corresponding inline citations .(August 2012) |