In 2005 the remains of a Tyrannosaurus rex (photo of the skeleton ©ScottRobertAnselmo) were found in Montana and so far the discovery was certainly interesting but not extraordinary. But when Mary Schweitzer, a paleontologist at the North Carolina Museum of Natural Sciences announced that she had found not only bones but also soft tissue, many remained skeptical. Today, this exceptional discovery has an explanation.
The soft tissues of animals generally decomposes by the action of bacteria. Even under optimal conditions that prevent decomposition, the proteins that make up those tissues tend to degrade over time. It can last for many thousands of years but scientists didn’t think they could get to last for millions of years. For this reason, skeptics thought that in the case of T.rex found in 2005 the tissue found was a product of a later bacterial invasion or something like that.
Mary Schweitzer and her colleagues started a careful analysis of tissue found in 2007 and established that it really belonged to the T.rex. Specifically, it was a type of collagen and its analysis gave interesting results showing similarities with bird collagen. This confirms that birds descended from dinosaurs of the theropoda group, to which T.rex belonged.
At that point, how a soft tissue was preserved for 70 million years remained to be explained. In a study published a few days ago, the answer given by Mary Schweitzer and her colleagues is that iron is responsible for that.
Iron is an element found in abundance in the body and especially in blood. It’s also highly reactive so it can form strong bonds with other molecules that protect them from degradation. Generally, after death iron forms small nanoparticles that can bind to cell and membranes in organic knots.
Mary Schweitzer and her colleagues found that the soft tissues of the dinosaurs is closely associated with the iron nanoparticles in the T.rex and also in the Brachylophosaurus canadensis, another animal of which soft tissue has been found. To test this hypothesis, they used blood vessels and bones of modern ostrichs. They soaked some blood vessels in hemoglobin, a molecule containing iron, and others in water. After two years, those soaked in hemoglobin remained intact while those immersed in water decomposed in less than a week.
The analysis of these soft tissues continue, albeit slowly because it’s a very delicate work. They might find pieces of T.rex DNA still intact but the indications in this regard are still too little. We’re still very far from the possibility of recreating dinosaurs Jurassic Park style but in some lucky cases we could discover new secrets about them.
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