When scientists uncovered a 68-million-year-old Tyrannosaurus rex fossil in Montana sandstone in 2000, they never expected to find traces of tissue. So when paleontologist Mary Schweitzer’s initial analysis of the fossil showed delicately preserved collagen protein, skepticism reigned. But in May, Schweitzer, of North Carolina State University, replicated the results and also announced a bigger find: a collection of even larger protein fragments from an 80-million-year-old duck-billed dinosaur called Brachylophosaurus canadensis. The fragments revealed more evidence of collagen and suggested the presence of two proteins—laminin and elastin—found in the blood vessels of animals.
“This type of preservation isn’t supposed to be possible,” Schweitzer says, “but here it is.” Her new discovery addressed many issues raised by critics of the T. rex work. For instance, her team adopted painstaking tactics to avoid contamination. In the lab, they used sterilized tools to sample the sandstone-encrusted thighbone, and specimens were quickly sealed in jars.
“Obtaining amino acid sequence data can show where extinct animals fit in the tree of life,” she says. “It’s a work in progress, but molecular paleontology might show us how dinosaurs are related to each other and even provide some physiological insights if we’re really lucky.”