This is a companion discussion topic for the original entry at https://biologos.org/blogs/guest/scientists-find-evidence-of-fossilized-dinosaur-brains
"Is genesis history?" film
Perhaps I am too cinematically influenced, but could there be DNA to sequence?
The brain got fossilized. Previous soft tissue fossilizations of dinosaurs have yielded no DNA sequences, so I doubt this one will.
I meant the T-Rex soft tissue. Is that just soft tissue fossilization or actual cellular material?
Good questions, Doug. Soft tissue, like bones, can be fossilized. Fossilization of soft tissue is much, much rarer than fossilization of bones, of course. As the title of this thread (“Scientists Find Evidence of Fossilized Dinosaur Brains”) suggests, the recent announcement referred to the discovery of fossilized brains, not actual cellular material.
Also, the article states it is an “endocast” so basically It sounds like a rock casting of the inside of the skull, sort of like lost wax casting techniques today. Still, pretty cool. I get confused with some of the terminology, not being in the field, so when terms like “preserved brain tissue” and “fossilized remains of soft tissue” are used, I am not real sure what that means, so perhaps we can clarify it. Is the actual soft tissue replaced with minerals that then approximate the anatomy, or did the brain rot away, and sediment fill the cranial cavity and cast the inside of the skull? I know that with some of the dino bones, there is thought that actual organic material may remain to a very limited extent, but am not sure if that is the case here.
These are good questions. A standard endocast is exactly what you describe: sediment filling the inside of the skull and hardening to produce a stone cast that approximates the shape of the brain. Much of the endocast under study here is just this. However, on the surface of the endocast, details are preserved that the authors argue represent the remains of actual soft tissue, not just sediments approximating the shape of the soft tissue. These apparent soft tissue remains have have been fossilized via mineral replacement, meaning that minerals from the surrounding sediments (in this case calcium phosphate and microcrystalline iron carbonate) have replaced the original organic content and preserved the most of the microscopic structure of the soft tissues. This is the first time an endocast like this has ever been reported. You’re also right that some of the dinosaur fossils in Mary Schweitzer’s work may contain actual soft tissue (e.g., blood vessels and red blood cells).