RE: Theropod Ontogeny

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Simon M. Clabby
>
> I'm not sure how to put this question scientifically,
> so I'll put it into laymans terms.
>
> Is you were to insert a peg into the top of the skull
> of a living theropod dinosaur as soon as it hatched
> (without killing it), if you went back to it when
> fully grown, would the peg still be in the middle of
> it's head, or would it has moved
> posteriorly/anteriorly?
>
> Basically, do theropods skulls grow anteriorly or
> posteriorly?
>
> I apologise for the slightly primary-school phrasing
> of this question. Please feel free to rephrase it
> scientifically/criticise.

In theropods, and dinosaurs generally, the rostrum (snout) grows faster than
does the rear of the skull, so in effect the peg would move "posteriorly"
(i.e., it would become progressively further back on the skull as a whole).

                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