RE: Archaeopteryx age-related taphonomy

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

> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] 
> On Behalf Of evelyn sobielski
>
> > This is unusual from an avian (sensu strictu = Neornithes) point of 
> > view, but not for a general dinosaurian point of view. The vast 
> > majority of dinosaur fossils are from subadults, not fully adult 
> > individuals.
> > 
> > If, as previous work indicates, the modern avian growth mode (where 
> > fully body sized is achieved in <1 yr) did not evolve until deep 
> > within Avialae, then there is no unusual phenomenon to 
> explain. It is 
> > simply the general dinosaurian growth pattern at work.
> 
> Certainly. I think a "saurian" mode of growth is null 
> hypothesis for Archie and perhaps 2as good as proven".
> 
> What puzzles me is that there is no known Archie hatchling, 
> and that there is only one juvie (there are 2 late subadults 
> and there are many mid-late subadults). Is this commmon?

Yes, hatchlings are very rare for most dinosaurs (esp. outside of eolian 
deposits).

Hone and Rauhut 
(http://onlinelibrary.wiley.com/doi/10.1111/j.1502-3931.2009.00187.x/abstract) 
discuss the possibility that high
levels of predation may be the reason that juveniles are so rare. Of course, 
taphonomy may be a factor too (especially for taxa
where the juveniles are orders of magnitude smaller than the adult).

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661               

Faculty Director, Science & Global Change Program, College Park Scholars
http://www.geol.umd.edu/sgc
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA