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RE: What did Spinosaurus eat? New species of Lepidotes found

On Sat, February 26, 2011 4:03 am, John Hunt wrote:
> Surely extant crocodilians could test this.  Some eat mostly fish, some
> hardly any.

A problem here is that absolute values of oxygen isotope ratios aren't
necessarily comparable outside of possible diagenetic change.

The best protocol to use is to sample individual fossils from the same
horizon of the same quarry of the same formation: this greatly reduces the
chance that the differences between values are due to slight variations in
preservation rather than what we are looking for: the actual distinction
between different isotopic ratios in life.

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