Michael Colunga (4 May 2011)
"RE:  Exactly when did the dinosaurs exist?"

Hello, John and Doves,
There are those of us who like to be able to shoehorn extra-biblical stuff into imagined interstices.
Then again, there are those of us [like myself] who are content, like Paul, to boast only of knowing Christ crucified [in my heart, by faith].  If He is not the center of our focus, then we will find ourselves wasting our waking hours wondering about vain questions.
When did dinosaurs exist?  They still do!  If you leave off the size characterization, you realize that man is still experimenting with genes as we speak!!!!  Have you not heard of frankencorn?  How about pit bulls?  I could go on and on.
In HaShem,
Mike C.