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RE: Serration variation

Could it also correspond then to a shift in prey and/or predatory
behavior?  Then the paedomorphosis hypothesis may have some weight. A  
small animal won't need serrations if it's eating insects or disgorged,
partially digested meat.  Serrations may be necessary in larger animals in
order for them to be effective predators.


On Thu, 10 Feb 2000, Thomas R. Holtz, Jr. wrote:

> > From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> > Dinogeorge@aol.com
> > Sent: Wednesday, February 09, 2000 7:48 PM
> >
> > In a message dated 2/9/00 7:35:38 PM EST, dbensen@gotnet.net writes:
> <
> > Neither behavior nor tooth shape has been shown to be independent of
> > phylogeny. So who knows what "more" means in this context. Also,
> > I don't know
> > of any theropod group in which >lost< tooth serrations were
> > >regained<. But
> > there were surely theropods that evolved serrated teeth
> > independently of one
> > another, from smaller (birdlike) theropods that had tiny, unserrated
> > teeth--the same kind as seen in Archaeopteryx.
> One thing to be concerned with is developmental constraints: some authors
> have suggested that  the constructional mechanisms required to place the
> serrations on teeth may only operate after the tooth is a certain size.
> Absence of serrations on very small teeth *might* thus be of developmental
> rather than phylogenetic significance.
>               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): 301-314-7843