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Re: Changyuraptor, new big microraptorine theropod from Early Cretaceous of China



We don't exclude other functions in the manuscript. Rather, the focus is on the 
performance effects the feathers would have related to aerial locomotion 
(sustained or not). These effects occur regardless of the selective landscape 
of the feathers. Since some of the performance outcomes are potentially 
advantageous (control of pitch, for example) we felt that referring to these as 
likely aerodynamic functions was warranted. Display-related or not, they will 
still produce fluid forces. Furthermore, the allometry of the feathers and tail 
length relative to body size is consistent with a pitch control hypothesis. 
This does not exclude display as an additional (or even primary) function.

Cheers,

--Mike H.

Sent from my Cybernetic Symbiote

> On Jul 15, 2014, at 12:57 PM, Jaime Headden <jaimeheadden@gmail.com> wrote:
> 
> "The lengthy feathered tail of the new fossil provides insight into
> the flight performance of microraptorines and how they may have
> maintained aerial competency at larger body sizes."
> 
> Oh, good. Glad they've ruled out display as a function of extremely
> long tail feathers. Or even extremely long leg feathers. We can't
> consider that on-flight-performance related factors may influence
> these structures, since they are so clearly only about flight, can we?
> Not to sound too sarcastic, but if that's in the abstract...
> 
> And why _Nature_? Yes, why _Nature Comm._?
> 
>> On Tue, Jul 15, 2014 at 8:17 AM, Ben Creisler <bcreisler@gmail.com> wrote:
>> Ben Creisler
>> bcreisler@gmail.com
>> 
>> A new paper:
>> 
>> Gang Han, Luis M. Chiappe, Shu-An Ji, Michael Habib, Alan H. Turner,
>> Anusuya Chinsamy, Xueling Liu & Lizhuo Han (2014)
>> A new raptorial dinosaur with exceptionally long feathering provides
>> insights into dromaeosaurid flight performance.
>> Nature Communications 5, Article number: 4382
>> doi:10.1038/ncomms5382
>> http://www.nature.com/ncomms/2014/140715/ncomms5382/full/ncomms5382.html
>> 
>> 
>> Microraptorines are a group of predatory dromaeosaurid theropod
>> dinosaurs with aerodynamic capacity. These close relatives of birds
>> are essential for testing hypotheses explaining the origin and early
>> evolution of avian flight. Here we describe a new ‘four-winged’
>> microraptorine, Changyuraptor yangi, from the Early Cretaceous Jehol
>> Biota of China. With tail feathers that are nearly 30 cm long, roughly
>> 30% the length of the skeleton, the new fossil possesses the longest
>> known feathers for any non-avian dinosaur. Furthermore, it is the
>> largest theropod with long, pennaceous feathers attached to the lower
>> hind limbs (that is, ‘hindwings’). The lengthy feathered tail of the
>> new fossil provides insight into the flight performance of
>> microraptorines and how they may have maintained aerial competency at
>> larger body sizes. We demonstrate how the low-aspect-ratio tail of the
>> new fossil would have acted as a pitch control structure reducing
>> descent speed and thus playing a key role in landing.
>> 
>> News stories:
>> 
>> http://www.slate.com/blogs/wild_things/2014/07/15/largest_flying_dinosaur_four_wings_on_changyuraptor_kept_it_from_crash_landing.html
> 
> 
> 
> -- 
> Jaime A. Headden
> The Bite Stuff: http://qilong.wordpress.com/
> 
> 
> "Innocent, unbiased observation is a myth" - P. B. Medawar (1969)