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* Working On The Porsche Of Its Time *

At 05:22 AM 1/6/2004, you wrote:
The reference to Porsche in a dinosaur story succesfully caught my
attention, but the article is interesting for a very different reason....

>Welcome to this edition of  DINOSAURNEWS.
>**  Working On The 'Porsche Of Its Time'
>Using all of the information available, palaeontologists must confront the
>fossil world reality that the classification of a new fossil species is
>subjective and varies among taxonomists

Part of the article refered to reads:
Because the Rauisuchian fossil record is generally sparse, Novak instead
dove into the dinosaurian fossil record in attempts to quantify the
amount of skeletal difference historically regarded as valid to erect a new species within the same
genera. She analyzed 28 genera containing 68 species from both the saurischian
(lizard-hipped) and ornithischian (bird-hipped) orders. Using the fact that the skeleton
of a dinosaur generally contains approximately 338 different bones, she catalogued the
number of differences as well as where the differences were found on the skeleton.
Calculations indicated that, on average, two species of dinosaur that are members of the same
genera varied from each other by just 2.2 percent. Translation of the percentage into an
actual number results in an average of just three skeletal differences out of the total 338 bones in
the body. Amazingly, 58 percent of these differences occurred in the skull alone.

"This is a lot less variation than I'd expected," said Novak, whose advisor is Josh Smith, Ph.D., Washington University assistant professor of Earth and Planetary Sciences. "As a concept, this is not statistically perfect. But I think it's something taxonomists can consider if they are in doubt over classifying something. It's a kind of benchmark with historical validity."

Novak was able to determine, using her Archosaurian Morphospecies Concept, that the Ghost Ranch Postosuchus was indeed the same species, Postosuchus kirkpatricki, as the two specimens from Texas.


Looks like Stephanie Novak is building the 'genericometer' that George is
after.  Very interesting.

Does anyone know of the citations for Novak's work?  Is she on this list (or
is Josh still on it?).  I'd be keen to hear more about this work.



Hi Colin. I am still here...sigh. Stephanie is currently feverishly readying manuscripts for submission regarding this research. Her results have so far been published as abstracts:

Novak, S. E. 2003. The Archosaurian Morphospecies Concept with Application to the Ghost Ranch Postosuchus. Geological Society of America Abstracts with Programs, v. 35: A

Novak, S. E. 2003. The postcranial skeleton of the Ghost Ranch Postosuchus with
special consideration of the Manus. Journal of Vertebrate Paleontology 23(3):83A.

Novak, S. E., Peyer, K, Carter, J.G., Weinbaum, J. 2002. A new specimen of Postosuchus
from the Late Triassic Newark Supergroup: Deep River Basin, North Carolina. Journal of
Vertebrate Paleontology 22(3):93A.

You might also check out:

Sues, H.D., J. G. Carter, P. E. Olsen, S. E. Novak, and K. Peyer. 2003. Life and Death in
the Late Triassic: An Extraordinary Tetrapod Assemblage from the Newark Supergroup of
North Carolina. Journal of Vertebrate Paleontology 23(3):102A.

She gave a good talk on this work at the latest GSA meeting in Seattle. I would recommend going to the source and emailing her directly:



------ Dr. Joshua B. Smith Assistant Professor of Geology Department of Earth & Planetary Sciences Washington University 1 Brookings Drive Campus Box 1169 108 Wilson Hall St. Louis, MO 63130-4899 Office: 314.935.7033 FAX: 314.935.7361 smithjb@levee.wustl.edu http://epsc.wustl.edu

Director, Bahariya Dinosaur Project