| During stretching of the wing down toward the ground, the alula is abducted from the wing and can be clearly viewed | Zhang, Fucheng; Zhou, Zhonghe 8 December 2000 , "A Primitive Enantiornithine Bird and the Origin of Feathers", Science, 290 5498 : 1955—1959, :, :, |
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| References [ ] Wikimedia Commons has media related to | [Al-Ola Governorate in Saudi Arabia] |
| There also are minor overlying the flight feathers | This functions in the same way as the on the wing of an aircraft, allowing the wing to achieve a higher than normal — and thus — without resulting in a |
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| The tip of the alula forms a tiny vortex that forces the airflow over the wing to better bind to it | 1994 , , Oxford University Press,• The city of forty Ain] |
The alula is the freely moving first digit, a bird's "thumb", and typically bears three to five small , with the exact number depending on the.
| Since these are not closely related to modern birds, either the alula twice, or it did so more than 130 million years ago | Chowdhury, Arka Roy 16 April 2018 |
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| Like the larger found on the wing's trailing edge, these alula feathers are asymmetrical, with the shaft running closer to anterior edge | The Alulae are particularly notable in |
[ ] In ancient birds [ ] The presence of an alula has been confirmed in several now- ancient relatives of , including an from the mid-, 115 and the earlier.
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