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RE: Dinosaur Planet, parts 3 & 4



> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Ken Carpenter
>
> Since Tom raises this issue:
> "There is now a cliche of the "hordes of newly hatched sauropods
> running for saftey in the trees" sequence, for which there is NO
> positive evidence. Simplest assumption by phylogeny: sauropod
> parents stayed near their own
> young through hatching into the first few weeks of life."
>
>
> I would take strong exception to this, noting that the "evidence"
> for parental care in the Dinosauria (even Jack's Maiasaura) is
> very weak and based mostly on inferences and assumptions.

That's why I said "simplest assumption by phylogeny".  Additionally, as
mentioned, I pointed out that the phylogenetic inference would be only
during the first few weeks of life (as in crocodilians): after that, they
might well have been on their own.

> What
> evidence there is indicates that the smallest footprints in track
> sites are half- or more adult size. There are NO baby tracks with adults.

But this might also be taphonomic, as a baby sauropod wouldn't be expected
to make a footprint except in soft sediment.  So unless the same tracksites
also preserve the footprints of non-sauropods of the same expected body size
as baby sauropods as well as the half-grown and larger ones, the possibility
remains that the absence is preservational.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796