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Re: [dinosaur] Enantiornithine Concornis and Eoalulavis flight reconstruction: bounding flight in Early Cretaceous birds.

Thanks Ben for sharing/updating, as always!

I just read through this paper, and itâs a solid piece of work. I 
particularly appreciated that the authors accounted for the drag estimation 
problems in the popular Flight 1.24 software when doing their power analysis. 
In terms of predicting bounding gaits for Cretaceous birds, this is definitely 
the most solid paper that Iâm aware of to date. Intermittent gaits, 
especially bounding, have been implicated variably as a solution to gearing 
constraints, anatomical constraints, and/or power limitations. This particular 
paper recovers some support for the gearing and/or anatomy arguments (since 
they donât find power to be limiting), but this paper also doesnât really 
test for potential bounding gait power advantages (it just tests if available 
power likely exceeded required power). Iâm curious what others think about 
the implications for origins of bounding flight.



Michael Habib, MS, PhD
Assistant Professor, Integrative Anatomical Sciences
Keck School of Medicine of USC
University of Southern California
Bishop Research Building; Room 403
1333 San Pablo Street, Los Angeles 90089-9112

Research Associate, Dinosaur Institute
Natural History Museum of Los Angeles County
900 Exposition Blvd, Los Angeles, CA 90007


> On Feb 21, 2018, at 9:12 AM, Ben Creisler <bcreisler@gmail.com> wrote:
> Ben Creisler
> bcreisler@gmail.com
> A new paper:
> Francisco J. Serrano, Luis M. Chiappe, Paul Palmqvist, Borja Figueirido, 
> JesÃs MarugÃn-LobÃn & Josà L. Sanz (2018)
> Flight reconstruction of two European enantiornithines (Aves, Pygostylia) and 
> the achievement of bounding flight in Early Cretaceous birds.
> Palaeontology (advance online publication)
> First published: 21 February 2018Full publication history
> DOI: 10.1111/pala.12351
> https://urldefense.proofpoint.com/v2/url?u=http-3A__onlinelibrary.wiley.com_doi_10.1111_pala.12351_abstract&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=ADSjRxMPspczKIot9xHUx8tNWB2Cl3bQxN6wJfk3d8g&s=6o09MFYLsbzBA9zVejsy14znyOrTb93B5J48siRsyHw&e=
> Intermittent flight through flap-gliding (alternating flapping phases and 
> gliding phases with spread wings) or bounding (flapping and ballistic phases 
> with wings folded against the body) are strategies to optimize aerial 
> efficiency which are commonly used among small birds today. The broad 
> morphological disparity of Mesozoic birds suggests that a range of aerial 
> strategies could have evolved early in avian evolution. Based on biomechanics 
> and aerodynamic theory, this study reconstructs the flight modes of two small 
> enantiornithines from the Lower Cretaceous fossil site of Las Hoyas (Spain): 
> Concornis lacustris and Eoalulavis hoyasi. Our results show that the short 
> length of their wings in relation to their body masses were suitable for 
> flying through strict flapping and intermittent bounds, but not through 
> facultative glides. Aerodynamic models indicate that the power margins of 
> these birds were sufficient to sustain bounding flight. Our results thus 
> suggest that C. lacustris and E. hoyasi would have increased aerial 
> efficiency through bounding flight, just as many small passerines and 
> woodpeckers do today. Intermittent bounding appears to have evolved early in 
> the evolutionary history of birds, at least 126 million years ago.
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