Re: Archaeopteryx Chimaera (was: Function Talks at Ostrom Symposium)

["Thomas R. Holtz, Jr." <th81@umail.umd.edu>]

At 08:51 PM 2/20/99 +0000, Luis Rey wrote:
>
>I have a strong suspicion why my previous question about Archaeopteryx has
>not (or cannot) been answered. Here it goes again.
>Since Archaeopteryx evidently does have a dinosaur skeleton and a dinosaur
>pelvis and theoretically should have had (in Ruben's theory) a diaphragm
>and the hepatic piston of a crocodile(?) does that mean that Archie IS NOT
>a bird and IS NOT in the bird lineage?

Ruben et al. do not consider Archie to have a "dinosaur pelvis": indeed,
they restore it with a hyperopisthopuby not justified by any of the
specimens.  Furthermore, they consider any similarities between the pelves
of dromaeosaurids and Archie to be superficial (although they consider the
pelves of theropods and crocodilians "strikingly similar"...).

With their new model of the Archaeopteryx pelvis, they suggest a
pelvic-driven pump in Archaeopteryx, as a forerunner to the modern bird
condition.  They do not think that Archie had a hepatic pistion.  (Hey, I
agree with them on this, at least).

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:tholtz@geol.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661