Jeholornis [1] ( lat. Jeholornis , “bird from Jehe ”) is a genus of primitive fossil birds from the Early Cretaceous , which lived about 120 million years ago. Fossil remains were found in the layers of the geological formation Tszyufotan (Jiufotang) in the Chinese province of Hebei [2] . After archeopteryx, geholornis are the most primitive birds known at the moment. They had a very long tail and several small teeth, were the size of a turkey, which makes them one of the largest birds of the Cretaceous period [3] .
| † Jeholornis |
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| Scientific classification |
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| No rank : | Bilateral symmetrical |
| Squad: | † Jeholornithiformes Zhou & Zhang, 2006 |
| Family: | † Jeholornithidae Zhou & Zhang, 2006 |
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| International scientific name |
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Jeholornis Zhou & Zhang, 2002 |
| Synonyms |
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- Jixiangornis Ji, Ji & Zhang, 2002
- Shenzhouraptor Ji et al. , 2002
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| Kinds |
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- J. prima Zhou & Zhang, 2002
- J. palmapenis O'Connor et al. , 2012
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Content
Jeholornis were relatively large, primitive birds, with a total body length of about 80 centimeters [4] . The Jeholornis had the so-called. buckle - fused bones at the end of the wing, which was absent in the Confuciusornis living at the same time. Particularly noteworthy was the tail. Usually in ancient birds it was quite short, and several vertebrae at its end fuse together, as in the pygostyle of modern birds. The tail of geholornis reached 42 cm in length and consisted of 22 separate vertebrae, which is typical for many dinosaurs [5] . In fact, the geholornis had two tails - one long, well preserved in fossil remains, and the second - wide and fan-shaped, formed by 11 feathers located above the base of the main tail. Such a “two-tailed” structure of geholornis is unique. The remains of both tails were found in six of the eleven available fossils of this genus [6] [3] [7] .
The skeleton of the geholornis was generally similar to the skeleton of an archeopteryx , with several key differences. The jaw was shorter, probably adapted for feeding seeds [6] . Unlike Archeopteryx, the jecholornis had no teeth in the upper jaw, and there were only three small teeth in the lower jaw. Their upper limbs were strong, larger than the lower ones, with a relatively well-developed shoulder girdle, which indicates strongly developed wing muscles [3] .
Imprints of more than 50 plant seeds the size of watermelon were preserved in the chest cavity of geholornis [5] .
