Re: origin of bats/reply 2 to TMK

[dinoboygraphics@aol.com]

> > That's a pretty safe assumption, based on the analyses done to date.<<

I beg to differ; historically the majority of workers just assumed 
flight without testing it.  Recent papers that deal with the issue are 
fairly split and point out several important constraints.  Archie may 
well have flown, but if so not in a manner very similar to crown group 
birds.


Scott Hartman
Science Director
Wyoming Dinosaur Center
110 Carter Ranch Rd.
Thermopolis, WY 82443
(800) 455-3466 ext. 230
Cell: (307) 921-8333

www.skeletaldrawing.com


-----Original Message-----
From: ptnorton@suscom-maine.net
To: dinoboygraphics@aol.com <dinoboygraphics@aol.com>; 
david.marjanovic@gmx.at <david.marjanovic@gmx.at>; dinosaur@usc.edu 
<dinosaur@usc.edu>
Sent: Mon, 23 Jun 2008 12:23 pm
Subject: Re: origin of bats/reply 2 to TMK



On 6/23/2008, "dinoboygraphics@aol.com" <dinoboygraphics@aol.com> wrote:

> Almost certainly?  In an organism that doesn't even preserve evidence
> of feathers on the thumb???

I said "analogous to". I did not say it had an alula. An alula
functions by affecting the air flow over the wing in a way that delays
stall. Clawed fingers, if elevated, could have performed that same
function.

> You are assuming apriori that archie a)
> flew,

That's a pretty safe assumption, based on the analyses done to date.

> and b) was arboreal.

I'm not assumming that at all. I agree with Mayer (2002?) that Archie
was likley facultatively arboreal, but not an obligate tree dweller.

> If you assume that archie landed in trees, then it sure seems like it
> had _better_ have an alula, but none of the specimens preserve evidence
> of such.

Again, it doesn't take too careful a reading of my post to see that I
did NOT say it had an alula, only the functional aerodynamic equivalent
of one in the exposed manus claws.

> not having an
> alula would be consistent with the lack of a reversed hallux, the short
> length of the hallux, the lack of strong felxor tubercles on the pes
> claws, the long non-sprawling hindlimbs,

These all point to the likelihood of Archie not being able to perch very
well, but have nothing to do with flight, per se.  They do support the
idea of Archie landing on trunks, rather than on branches, as I suggest.

PTJN