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Re: The hands of Titanis



-----Original Message-----
From: fredericus ruhe <fredruhe@xs4all.nl>
To: dinosaur@usc.edu <dinosaur@usc.edu>
Date: Monday, July 31, 2000 6:46 PM
Subject: Re: The hands of Titanis


>
>The last thing I red about this subject was in:
>
>Chandler, R.M. (1994): The wing of Titanis walleri (Aves:Phorusrhacidae)
>from the late Blancan of Florida. Bulletin of the Florida Museum of Natural
>History Biological Sciences 36(6), pp. 175 - 180.
>
>Fred
>
>At 15:03 31-07-2000 DST, you wrote:
>>
>> Dear all
>>
>>Some time ago, there was an interesting re-evaluation of the fitness of
the
>extinct predatory ground birds of North America in the Discovery magazine.
>It was claimed that Titanis, and probably some other Phorusrhacids too, had
>their wings modified into arms bearing flexible fingers ending in mighty
>claws. The evidence on which this was based, was that the structure of the
>wrist joint didn't permit folding the arm, the humerus was solid bone, and
>thumb attached to the carpometacarpus via a mobile ball and socket joint.
No
>ulna, radius, nor any fingers or claws had actually been found.
>>
>>As I recently browsed the archives of the Dinosaur Mailing List, I came
>across with messages postulating that the hands of Titanis were monodactyl,
>like Mononykus, and that evidence for the presence of claws had been found.
>Have some new bones emerged frome the ground? I have completely missed the
>evidence for monodactylu in Titanis. Could somebody tell me from what these
>new hypotheses have been derived?
>>


I happen to possess a copy of Discover (June 1997) with the article on
Titanis "Terror Take Two" by Carl Zimmer,....(assuming this is the article
referred to). The article shows a mount with folded vestigial wings, that is
stated to be incorrect, as well as a couple of painted drawings of the
creature as it would appear in real life (most likely based on Chandler`s
new findings) that show three digits. Digit 1 is offset at almost right
angle to manus, is ball and socket, and has a claw. Digits two and three are
fused, with a large single claw emanating from digit 2. The carpometacarpus
seems "locked" in straight line with the radius, ulna. This seems also the
pose most represented in Mononychus (is Mono`s wrist also "non-bendable"?).
A solid humerous (as opposed to pneumaticized) is said to have evolved
through active use of the forearms for fending off struggling prey(which
were dispatched mainly by use of it`s large beak). Did Mononychus have a
"solid humerous"?