Smithsonian (Link) - Helen Fields (May, 2006)
Neatly dressed in blue Capri pants and a sleeveless top, long hair flowing over her bare shoulders, Mary Schweitzer sits at a microscope in a dim lab, her face lit only by a glowing computer screen showing a network of thin, branching vessels. That’s right, blood vessels. From a dinosaur. “Ho-ho-ho, I am excite-e-e-e-d,” she chuckles. “I am, like, really excited.
After 68 million years in the ground, a Tyrannosaurus rex found in Montana was dug up, its leg bone was broken in pieces, and fragments were dissolved in acid in Schweitzer’s laboratory at North Carolina State University in Raleigh. “Cool beans,” she says, looking at the image on the screen. It was big news indeed last year when Schweitzer announced she had discovered blood vessels and structures that looked like whole cells inside that T. rex bone—the first observation of its kind. The finding amazed colleagues, who had never imagined that even a trace of still-soft dinosaur tissue could survive. After all, as any textbook will tell you, when an animal dies, soft tissues such as blood vessels, muscle and skin decay and disappear over time, while hard tissues like bone may gradually acquire minerals from the environment and become fossils. Schweitzer, one of the first scientists to use the tools of modern cell biology to study dinosaurs, has upended the conventional wisdom by showing that some rock-hard fossils tens of millions of years old may have remnants of soft tissues hidden away in their interiors. “The reason it hasn’t been discovered before is no right-thinking paleontologist would do what Mary did with her specimens. We don’t go to all this effort to dig this stuff out of the ground to then destroy it in acid,” says dinosaur paleontologist Thomas Holtz Jr., of the University of Maryland. “It’s great science.” The observations could shed new light on how dinosaurs evolved and how their muscles and blood vessels worked. And the new findings might help settle a long-running debate about whether dinosaurs were warmblooded, coldblooded—or both.