Aepyornis is a genus of aepyornithid, one of three genera of ratite birds endemic to Madagascar until their extinction sometime around 1000 A.D. The species A. maximus weighed up to, and until recently was regarded as the largest known bird of all time. However, in 2018 the largest aepyornithid specimens, weighing up to, were moved to the related genus Vorombe.
Taxonomy
Brodkorb listed four species of Aepyornis as valid: A. hildebrandti, A. gracilis, A. medius and A. maximus, However, Hume and Walters listed only one species, A. maximus. Most recently, Hansford and Turvey recognized only A. hildebrandti and A. maximus.
The nominal species Aepyornis titan Andrews, 1894 was placed in the separate genus Vorombe by Hansford and Turvey, with A. ingens a synonym of titan. Aepyornis grandidieri Rowley, 1867 is an ootaxon known only from an eggshell fragment and hence a nomen dubium. Hansford and Truvey also found Aepyornis modestus a senior synonym of all Mullerornis nominal species, making modestus the epithet of the Mullerornis type species.
Evolution
Like the cassowary, ostrich, rhea, emu and kiwi, Aepyornis was a ratite; it could not fly, and its breast bone had no keel. Because Madagascar and Africa separated before the ratite lineage arose, Aepyornis has been thought to have dispersed and become flightless and giganticin situ. More recently, it has been deduced from DNA sequence comparisons that the closest living relatives of elephant birds are New Zealandkiwis, indicating that the ancestors of elephant birds dispersed to Madagascar from Australasia.
Etymology
Aepyornis maximus is commonly known as the 'elephant bird', a term that apparently originated from Marco Polo's account of the rukh in 1298, although he was apparently referring to an eagle-like bird strong enough to "seize an elephant with its talons". Sightings of eggs of elephant birds by early sailors could also have been erroneously attributed to a giant raptor from Madagascar. The legend of the roc could also have originated from sightings of such a giant subfossil eagle related to the African crowned eagle, which has been described in the genus Stephanoaetus from Madagascar, being large enough to carry off large primates; today, lemurs still retain a fear of aerial predators such as these. Another might be the perception of ratites retaining neotenic features and thus being mistaken for enormous chicks of a presumably more massive bird.
Description
Aepyornis, which was a giant, flightless ratite native to Madagascar, has probably been extinct since at least the 11th century. Aepyornis was one of the world's largest birds, believed to have been up to tall, with weights in the range for A. hildebrandti and for A. maximus. Remains of Aepyornis adults and eggs have been found; in some cases the eggs have a circumference of over and a length up to. The egg volume is about 160 times greater than a chicken egg.
Nocturnality
s of aepyornithid skulls have shown that these animals had poor eyesight and large olfactory bulbs, much like living kiwis. This has been interpreted as a sign that, like them, elephant birds were nocturnal.
It is widely believed that the extinction of Aepyornis was the result of human activity. The birds were initially widespread, occurring from the northern to the southern tip of Madagascar. One theory states that humans hunted the elephant birds to extinction in a very short time for such a large landmass. There is indeed evidence that they were killed. However, their eggs may have been the most vulnerable point in their life cycle. A recent archaeological study found fragments of eggshells among the remains of human fires, suggesting that the eggs regularly provided meals for entire families. dinosaurs The exact time period when they died out is also not certain; tales of these giant birds may have persisted for centuries in folk memory. There is archaeological evidence of Aepyornis from a radiocarbon-dated bone at 1880 +/- 70 BP with signs of butchering, and on the basis of radiocarbon dating of shells, about 1000 BP. It is thought that Aepyornis is the Malagasy legendary extinct animal called the vorompatra, Malagasy for "marsh bird". After many years of failed attempts, DNA molecules of Aepyornis eggs were successfully extracted by a group of international researchers and results were published in the Proceedings of the Royal Society B. It has also been suggested that the extinction was a secondary effect of human impact due to transfer of hyperdiseases from human commensals such as chickens and guineafowl. The bones of these domesticated fowl have been found in subfossil sites in the island, such as Ambolisatra, where Mullerornis sp. and Aepyornis maximus have been reported. David Attenborough in a BBCTelevision program transmitted in early 2011 said that "very few Aepyornis bones show signs of butchery, so likely there was a Malagasy native taboo against killing Aepyornis, and that is likely why Aepyornis survived so long after Man arrived there". But that does not say anything about whether the natives took so many Aepyornis eggs that the species died out.
