By Davide Castelvecchi
Fossils are the remains of ancient organisms, typically turned into stone by millions of years of mineralization. That’s why fossil soft tissue sounds like an oxymoron. Yet that’s what paleontologists have found in March inside the femur of a T. rex: blood vessels, bone cells and perhaps even blood cells.
The bone had rested in a remote Montana location since the late cretaceous, 70 million years ago. Its discoverers had to cut it up to transport it by helicopter. When they did so, they noticed some unusual, spongy texture where the bone marrow used to be. After removing minerals with solvents, the scientists were left with rubbery, soft vessels that looked like veins — and even seemed to contain blood.
Scientists now hope to find proteins whose presence could solve some long-standing mysteries about dinosaurs, such as whether they were cold-blooded like reptiles or warm-blooded like birds. Finding bits of DNA — let alone recreating live dinosaurs — will be a long shot, but people will certainly try. Others caution that the rubbery texture does not guarantee that the original chemistry was preserved: soft fossils have been discovered before, where the original organic material had gone.
Some paleontologists also think that more soft tissue could be found by slicing up dinosaur bones preserved in museums. The finding is also forcing geologists to take a new look at the process of fossilization, since nobody has the slightest idea how such structures could have been preserved.