Tyrannosaurus rex 68 million years old This specimen is the same T. rex as that reported on in Schweitzer's 2005
study. Hollow, translucent, and still-supple blood vessels were common in this
specimen. The vessel shown here has more of those "round, red
microstructures" and is distinguished by a particularly thick vessel
wall. Since DNA is presumed to be fragile—the oldest yet discovered is
from Neanderthal fossils roughly 50,000 years old—Schweitzer's team
has so far focused on finding proteins, which are more durable. Recently they
announced they had found protein in a T. rex specimen, in the form of collagen.