2011-07-07 11:52:14
Pelagornithids are an extinct family of large seabirds that dominated the world’s oceans from the Upper Paleocene, just under 60 million years ago, to the early Pleistocene, 2.5 million years ago. Its fossil remains have been found in Europe, Africa, Japan, North America, South America, New Zealand, and Antarctica. The most notable distinguishing feature of pelagornithids is the presence of teeth on the edges of the beak. These are not true teeth, like the ones Archeopteryx had, but rather extensions of the jaw bones.
The oldest and smallest species of pelagornithids were as large as today’s albatross, and the largest were gigantic, with wingspans of up to twenty feet, second only to the Argentavis, the Miocene-era South American bird of prey.
The bones of the pelagornithids were very thin and light, filled with air sacs thanks to which they reached their enormous size without increasing their weight too much. For this reason, their fossils are often found crushed or even crushed, so their reconstruction is difficult. Neither are it easy to establish the kinship relationships between the pelagornithids and the different families of current birds. At first they were classified as an intermediate group between pelicans and albatrosses, but today it is known that they are more closely related to the former, and their similarity to the latter is a phenomenon of evolutionary convergence due to their similar way of life. Although other analyzes seem to indicate a closer relationship with ducks.
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