[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

FW: Microraptor hanqingi, new species from China.




I second Dr. Habib on that. Some papers on quail and starlings showed that 
something like 90% of their launch velocity came from leaping with their legs, 
from a  standstill, and only 10% from their modern pectoral flight apparatus. 
Until then I never imagined the legs provided so much thrust. The kagu is said 
to start at a  standstill, leap up with its legs, and glide downhill, but I 
investigated that and it is suspect. We'd have to test one in a  zoo to see if 
they can really do it without flapping.
________________________________________
From: owner-DINOSAUR@usc.edu [owner-DINOSAUR@usc.edu] on behalf of Habib, 
Michael [MHabib@Chatham.edu]
Sent: Friday, May 25, 2012 4:36 PM
To: Augusto Haro
Cc: d_ohmes@yahoo.com; "dinosaur@usc.edu"@listproc.usc.edu
Subject: Re: Microraptor hanqingi, new species from China.

The inability of Archaeopteryx to flap is actually quite debatable, but 
regardless, there are many other ways to use wings than gliding, even without 
powered flight. Incidentally, if it launch from the ground (huge if) there's no 
particular reason to expect it ran to do so.

--Mike


On May 25, 2012, at 3:09 PM, Augusto Haro wrote:

> 2012/5/25 Habib, Michael <MHabib@chatham.edu>
>
> Also, for all of the individuals in the current thread: we should be sure to 
> give good cause at each step for putting paravians in trees to begin with.  
> The potentially intuitive nature of arboreal proto-flight does not constitute 
> good cause.
> In my case, when I tought best of the hypothesis of tree-down origin of avian 
> flight, my main reasons were:
>
> 1- Reading that Archaeopteryx could not flap, being thus forced to glide or 
> soar (if such a form got into the air at all), coupled with the impression 
> that these wings had to be used to travel on air away from the floor 
> (contrasting with merely ornamental or egg-protecting hypotheses, which I 
> cannot refute, BTW), and reading in some aged book that Archaepteryx could 
> not start gliding from the floor even if it was acquiring velocity by running 
> (I do not remember the physical ar
ke to know if it is true), so being forced to start from above.
> 2 - Although now obsolete, Fedduccia's (1993) argument on ungual curvature.
>
> Other alternative scenario for a gliding origin of flight would be, as 
> previously mentioned by someone, very "rugous" or irregular terrain, which 
> would permit economy of transport for gliders and by the way would likely be 
> avoided by larger predators because of the possibility of tripping over. Can 
> the "rugosity" of the terrain in which avialans are found be geologically 
> assessed?
>
> An alternative is that Archaeopteryx's vertically jumping capacities were 
> awesome (given some similarity of jumping and cursorial adaptations, and the 
> arguments raised by Tim against aboreality, this is now slightly sound to me, 
> but there do not seem to be present specifically jumping adaptations).

Michael Habib
Assistant Professor of Biology
Chatham University
Woodland Road, Pittsburgh PA  15232
Buhl Hall, Room 226A
biologyinmotion@gmail.com
(443) 280-0181