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Re: Where are the egg shells

This is possible, but there are other possibilities:

1) It was not a nesting burrow, but a living burrow.

2) Eggshell WAS present, but was lost during diagenesis.

3) Eggshell WAS present, but was lost during preparation.

There are other possibilities as well.

On Tue, July 9, 2013 4:27 pm, john-schneiderman@cox.net wrote:
> Bakker (1990) described tightly-packed pods of 6 to 35 individuals which
> he interpreted as representing groups of Drinker in burrows, perhaps
> drowned by flooding or killed by disease. If Drinker was indeed a
> burrower, it would be among the first known for dinosaurs; the only
> well-supported published case of a fossorial nonavian dinosaur is the
> more recently discovered, distantly related Oryctodromeus. One problem
> with Bakker's interpretation was the lack of fossilized egg shell
> fragments amongst the individuals which he stated (1992) was a family
> group of many juvenile/hatchlings with adults within a nesting burrow
> found in Como Bluff, Wyoming.
> Supporting the nesting burrow idea, is it possible that a behavior
> amongst Drinker, and possibly other small ornithopods, were for the
> adults to consume the egg shell fragments after the the babies hatched
> as a means to replenish their loss of calicum, and thus no egg shell
> fragments to be found in the nest? Egg and egg shell eating is common
> amongst the birds ("Dinosaurs") today.
> References:
> -- Bakker, R.T., Galton, P.M., Siegwarth, J., and Filla, J. (1990). A
> new latest Jurassic vertebrate fauna, from the highest levels of the
> Morrison Formation at Como Bluff, Wyoming. Part IV. The dinosaurs: A new
> Othnielia-like hypsilophodontoid. Hunteria 2(6): 8-14.
> -- Bakker, R.T. (1990). A new latest Jurassic vertebrate fauna, from the
> highest levels of the Morrison Formation at Como Bluff, Wyoming, with
> comments on Morrison biochronology. Part I. Biochronology. Hunteria
> 2(6):1-3.
> -- Bakker, R. T. (1997). "Dinosaur mid-life crisis: the
> Jurassic-Cretaceous transition in Wyoming and Colorado". In Lucas, S.G.,
> Kirkland, J.I., and Estep, J.W. (eds.). Lower and Middle Cretaceous
> Terrestrial Ecosystems. New Mexico Museum of Natural History and Science
> Bulletin 14. New Mexico Museum of Natural History and Science. pp.
> 67â??77.
> -- Varricchio, David J.; Martin, Anthony J.; and Katsura, Yoshihiro
> (2007). "First trace and body fossil evidence of a burrowing, denning
> dinosaur". Proceedings of the Royal Society B: Biological Sciences 274
> (1616): 1361â??1368.
> -- Dinosaur Parents, Dinosaur Young: Uncovering the Mystery of Dinosaur
> Families By Kathleen Weidner Zoehfeld;  HMH Books for Young Readers
> (January 22, 2007) ISBN-10: 0618752447 pgs: 31-32.

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
Fax: 301-314-9661

Faculty Director, Science & Global Change Program, College Park Scholars
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