Argentavis magnificens
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Argentavis Temporal range: Late Miocene (Huayquerian) ~9.0–6.8 Ma |
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| Reconstruction of A. magnificens | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Accipitriformes |
| Family: | †Teratornithidae |
| Genus: |
†Argentavis Campbell & Tonni 1980 |
| Species: | †A. magnificens |
| Binomial name | |
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Argentavis magnificens Campbell & Tonni, 1980 |
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Argentavis magnificens ("magnificent Argentine bird", or more literally "magnificent silver bird") was among the largest flying birds ever to exist, quite possibly surpassed in wingspan only by the recently discovered Pelagornis sandersi. A. magnificens, sometimes called the giant teratorn, is an extinct species known from three sites in the Epecuén and Andalhuala Formations in central and northwestern Argentina dating to the Late Miocene (Huayquerian), where a good sample of fossils have been obtained.
The single known humerus (upper arm bone) specimen of Argentavis is somewhat damaged. Even so, it allows a fairly accurate estimate of its length in life. Argentavis's humerus was only slightly shorter than an entire human arm. The species apparently had stout, strong legs and large feet which enabled it to walk with ease. The bill was large, rather slender, and had a hooked tip with a wide gape.
Argentavis had an estimated wing span of 5.09 to 6.07 m (16.7 to 19.9 ft) (depending on the method used for scaling, i.e. regression analyses or comparisons with the California condor), a height of circa 1.5 to 2 m (4.9 to 6.6 ft), and a mass of approximately 70 to 72 kg (154 to 159 lb). This made it the largest bird until another extinct species, Pelagornis sandersi, was described in 2014 as having a larger size (although only weighing 22–40 kg). For comparison, the living bird with the largest wingspan is the wandering albatross, at 3.6 m (12 ft). Since A. magnificens is known to have been a land bird, another good point of comparison is the Andean condor, one of the largest extant land birds, with a wingspan of up to 3.2 m (10 ft) and weight of up to 15 kg (33 lb), and which is not too distantly related to Argentavis.
The ability to fly is not a simple question of weight ratios, except in extreme cases; size and structure of the wing must also be taken into account. As a rule of thumb, a wing loading of 25 kg/m2 is considered the limit for avian flight. The heaviest extant flying birds are known to weigh up to 21 kg (46 lb) (there are several contenders, among which are the European great bustard and the African kori bustard). A mute swan, which may have personally lost the power of flight due to extreme weight, was found to have weighed 23 kg (51 lb). Meanwhile, the sarus crane is the tallest flying bird alive, at up to 1.8 m (5.9 ft) tall, standing about as high as Argentavis due to its long legs and neck.
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Wikipedia