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Re: New Ruben Paper



Additionally, it should be noted that the whole "temporal
incongruence" argument has been examined in detail by Brochu and
Norell (2000) and Pol and Norell (2006). These authors demonstrated
that the placement of avian dinosaurs as the sister taxon to certain
derived theropod dinosaurs was more congruence with the fossil record
of first appearances than any other proposed avian origin.

Also, we have to remember that cladistic hypotheses place birds as the
SISTER TAXON to a clade of derived theropod dinosaurs. They DO NOT
point to any one dinosaurian taxon as being the direct ancestor of
these two clades, and  the exact most recent common ancester of the
two is not likely to ever be found, or recognized even if found.
Therefore, there is almost always some temporal disparity between when
members of two sister clades are recognized in the fossil record. And
as others in this discussion thread have pointed out, the size of this
temporal disparity is shrinking based on new finds.

In summation, the entire "temporal incongruence" argument has been
null and void since it was first proposed, as it relates to an
inaccurate understanding of the assumptions behind cladistic analyses.

Clint Boyd.

P.S.- I also enjoy the temporal paradox behind birds not being related
to dinos because they have certain traits that dinosaurs don't, but
neither does any other animal. Therefore, only birds could give rise
to birds. I proposed that this is direct evidence that mankind will
invent time travel in the future, only to accidentally let a flock of
birds escape to the Jurassic, giving rise to all of avialae. I name
this the Fry effect (for anyone familiar with futurama).
--
C. Aaroen Boyd
PhD Candidate
Jackson School of Geosciences
The University of Texas at Austin
cab@mail.utexas.edu

References:

Brochu, C.A., Norell, M.A., 2000. Temporal congruence and the origin
of birds. J. Vertebr. Paleontol. 20, 197-200.

Pol, D., Norell, M.A., 2006. Uncertainty in the age of fossils and the
stratigraphic fit to phylogenies. Sys. Bio. 55, 512-521.