So, I found out yesterday that scientists have discovered a very well-preserved hadrosaur, one that was so well-preserved as to actually retain skin, muscles and possibly even internal organs (once analyses are completed on the fossil).
As a student of anthropology and an armchair paleontologist since the age of five, I have a fair-to-middling understanding of how fossilization works. It’s tricky enough to get it to leave the impressions of the bone once the mineral replacement process goes through; how on Earth could frickin’ soft tissues fossilize?
Also, what is it with hadrosaurs getting themselves stuck in swamps and mummifying? I recall reading about a well-preserved Edmontosaurus a few years ago. Were these dinos stupid, getting themselves stuck all the time, or did they just hang out in swamps a lot, and we see this by sheer probabilistic blip (as opposed to seeing a lot of, say, mummified T. rexes)?
Furthermore, how many bad horror movies will be spawned if this discovery makes it to the public attention? Shambling, mummified hadrosaurs, quacking and eating your neighbor’s rosebushes — I can just imagine…
As far as I’m concerned, fossilization falls strictly under the “magic” category. I get that individual molecules, or atoms, or cells or somethings are replaced with stone molecules, or atoms or crystals or somethings. Ok, check. But how on earth can they tell the skin was striped? Do only brown rock molecules replace brown skin cells, and white rock molecules replace white skin cells? And what about the innards - why doesn’t the rock that takes over the rib just meld with the rock that takes over the intercostal muscles?
I watched the Nat. Geographic special - they infer that the skin was striped because the scale patterns change. A strip of small scales, then a strip of larger scales, then smaller, etc. In modern reptiles, this change in scale size is usually correlated with a change in color, so they’re assuming the same thing happened with dinosaurs.
Stephen Jay Gould’s book ‘Wonderful Life’ concerns the preservation of the Burgess Shale where soft parts of creatures 500 million years old were preserved in a low oxygen sea environment under fortuitous (for us) mudslides. I frankly didn’t finish the book. Presumably these sort of preservation conditions occur more often in ancient marine environments though.
Any info on why it’s not just a dino-shaped boulder of rock, but has identifiable (to the wizards) parts discrete enough to show internal anatomy? I’m aware that this is like 7th grade stuff I never fully understood…
I presume the tannins found in the waters of a bog essentially turned the beasts into leather. I presume it’s a similar phenomenon to that seen in bog bodies - the preserved remains of humans found in the peat bogs of northern Europe.
One thing confuses me, though. It’s my understanding that bone tissue is not preserved in the bog bodies, since the acid in the peat destroys calcium carbonate. So if the same process was at work on the Hadrosaurs, how do we have bones? Or was it a different process?
No, these are rock, same as other fossils. But I think maybe they were bog leathered *before *they were made rock, so instead of having a fossil of a skeleton and maybe a scrap of skin, they have a fossil (rock) of nearly the whole beast, muscles and organs and everything.
Sorry, mine is a really stupid question about a really basic fundamental part of fossil formation I just don’t get. But it’s such a stupid question that I can’t find an answer at a level I can understand. It’s always explained, “So the mineralization of the body takes place over a long period of time, where the molecules in the carcass are replaced with molecules of minerals.” And everyone else nods and goes, “uh-huh” and the lecture proceeds, and I’m all:
No kidding. Since when has *Tyrannosaurus rex * been established as a scavenger? Just how many large carnivores are known to subsist on a diet of carrion, to the exclusion of active predation?
In the podcast I first got the information from (a source none other than “This Week in Science”), one of the hosts took the fact that this hadrosaur could have run as fast as 28 miles per hour as evidence that Rexy was a scavenger, because he could only run about 19 miles per hour. To which I thought, “Bullshit — Rexy could have been an ambush predator.”
Of course, hadrosaurs probably had a good sense of smell, and I imagine a five-ton carnivore probably smelled pretty strongly, complicating its attempts to hide in the undergrowth…
People often express surprise at how something delicate could be fossilised and last so very long, but the point is - once it’s fossilised (which can be quite a rapid process), it’s pretty stable and inert, and can then last pretty much forever.
That host’s conclusion is pretty funny, considering that the new estimate of the hadrosaur’s speed is based on the muscle volume calculated from this uniquely well-preserved specimen. Presumably the older, slower estimate of hadrosaur speed was arrived at in the same manner used to evaluate tyrannosaur speed. So comparing the two estimates seems like a case of apples and oranges, since we don’t have a comparably well-preserved tyrannosaur carcass. If we now know that the hadrosaur’s muscle volume was underestimated, doesn’t it seem likely that the tyrannosaur’s muscle volume has been underestimated as well?
Keep in mind that the ones who were hanging out in swamps were more likely to be fossilized. Very few organisms end up as fossils, so it’s not surprising that the ones who do were in a fossil-friendly environment in the first place. Hadrosaurs were grazers, though, so they may very well have found swamps to be apettizing places to hang out in. If so, they would have just died there, and needn’t have gotten stuck.
Watched the same show on Nat. Geo the other day. Fascinating. To answer your question, the show made references to hadrosaurs being the ‘cows’ or ‘bison’ of their period…and suggested they ran in very large herds. So, my guess would be on the ‘probabilistic blip’ theory…there were a LOT of these things kicking around in areas where they were most likely to have this occur. So, even though the odds of it happening to any individual animal were vanishingly remote, couple a lot of said animals in the optimal place over large periods of time and there you go. Fossilized dino skin.
The browser/grazer distinction doesn’t really apply to dinosaurs, as it is a measure of the relative amounts of grasses which make up one’s diet. Grasses, as I’m sure you’re aware, weren’t around during much of the Mesozoic (recent evidence puts some varieties at the very end of the Cretaceous).
Hadrosaurs were adapted to eat lots of plants, typically hard stuff. They had batteries of grinding teeth to rival just about any mammal, so were capable of eating practically any plant matter they could wrap their ample mouths around.
In the article you linked, it explains that the specimen was mummified first, then fossilized. Thus, the mummificiation process keeps some soft tissues around long enough for them to still be present once actual fossilization begins. So the specimen is still a fossil with everything replaced by minerals and such, not a mummy; it’s a fossil of a mummy.
It hasn’t. That’s one of Jack Horner’s pet theories, but it hasn’t reached any real scientific consensus as yet. Horner is firmly in the “large dinosaurs couldn’t run” camp, thus his belief that T. rex and its ilk were scavengers rather than active predators.
There was an anatosaur “Dinosaur Mummy” in the Hall of Cretaceous Dinosaurs at the American Museum of Natural History back when I was a kid in the 1960s. Anatosaurs were related (distantly) to hadrosaurs. I recall the exhibition label pointing out the patterns of scales on the mummy. It’s not as if this hasn’t been found before. But I don’t recall there ever being such suggestive evidence of stripes before – there’s been plenty of speculation, but, as far as I can recall, no evidence.
Anatosaurus is an obsolete name for Edmontosaurus, which is a proper hadrosaur by any definition.
Oddly enough, though, given the fragmentary nature of Hadrosaurus, the beasty after which all hadrosaurs are named, it’s possible that Hadrosaurus may not itself be a hadrosaur.
