Fossilised dino brain unearthed for first time
The past 12 months have been exciting for palaeontologists.
Towards the end of last year scientists confirmed a fossil unearthed more than a decade ago actually contains a piece of fossilised dinosaur brain tissue — the first ever found.
The 133-million-year-year-old fossil comes from a species known as Iguanodon, and shows a brain structure similar to that of modern day crocodiles and birds.
Researchers examined the fossilised tissue under a microscope and saw what looked like blood vessels coming out from the brain’s interior.
Scientists also spent the year discovering the world’s biggest dinosaur footprints, located in Western Australia, and new information showing the T. rex was not much of a sprinter.
When you think of dinosaur fossils, you probably think of bones, the scientific riddle of putting those bones together and figuring out where all the meat and guts went. You certainly wouldn’t expect to discover a cache of dinosaur blood while digging around in your backyard. And if you soaked a dinosaur bone in acid, it wouldn’t dissolve into gristle.
Or would it?
This question became a controversial topic of discussion in 2005 when a team of North Carolina State University paleontologists published a paper titled “Soft tissues are preserved within hindlimb elements ofTyrannosaurus rex” in the journal Science.
Scientist Mary Schweitzer and her team had placed a fossilized T. rex bone fragment in an acidic demineralizing bath to study its components and let the process take its full course. If the fossil had been nothing but rock, the bath would have dissolved absolutely everything.
Instead, the process left behind soft tissue. When analyzed, the tissue appeared to be the blood vessels, bone matrix and osteocytes (the cells that build bone) of a 68-million-year-old dinosaur. For a full account of the study and the controversy that followed, read;
Theories vary on how soft tissue survived 68 million years, but Schweitzer hypothesized that densely mineralized bone somehow protected the inner structures. In other cases, however, dinosaur soft tissue fossilized along with the bones. When paleontologists unearthed the remains of a 77-million-year-oldBrachylophosaurus canadensis in 2000, they discovered its skin, scales, muscle, footpads and stomach contents mineralized as fossil.
Soft tissue fossilization is rare, however, due to decomposition and scavengers. In most cases, dinosaur meat simply wound up in the bellies of other organisms or rotted in the sun. Then, in some instances, sediment covered the bones and enabled the long, slow process of fossilization to begin.
Not surprisingly, soft tissue fossilization occurs most often in creatures that lived in the sediment, like the trilobite, a seafloor arthropod. Large land animals like dinosaurs, however, would have to suffer a rare catastrophic burial — such as death by landslide., or major flood.
Schweitzer’s findings make perfect sense. In the view of young-Earth creationists, soft tissue is proof that fossils aren’t as old as scientists report. After all, according to scientific estimates, T. rexfossils are 65 million years old. Soft tissue and amino acids should last only a fraction of that time. Someone who believes the Earth is less than 10,000 years old may see Schweitzer’s find as compelling evidence for a young Earth rather than a cause to re-examine the nature of fossilization. However, analysis using radiometric dating — the method scientists use to determine the age of fossils — conflicts with the idea of a 10,000-year-old Earth.
Schweitzer offers hypotheses for how the tissue could have survived so long. One is that the densely mineralized bone, combined with as-yet-undiscovered geological or environmental processes, protected the structures within [source: Schweitzer, 3/25/2005]. And regardless of whether the paleontological community eventually embraces or refutes the tissue in question, the find does seem to make ideas that used to be impossible merely improbable.