Tyrannosaurus rex 65 million years old The team examined a number of T.
rex specimens, several of which revealed
what Schweitzer cautiously terms "round, red microstructures," as
vividly pictured here. Further tests will determine whether they are truly red
blood cells from the animal, or if they are some remnant of the fossilization
process that mimics them. If they are cells, could DNA have survived within?
Again, further tests should tell, though most experts agree it's a long
shot. The yellow material surrounding the vessel seen here is fibrous bone
matrix containing bone cells.