Posted on 06/02/2005 2:06:01 PM PDT by dread78645
WASHINGTON (Reuters) - A Tyrannosaurus rex dinosaur that died 68 million years ago has provided some of the strongest evidence yet that birds are the closest-living relatives of dinosaurs, scientists said on Thursday.
Soft tissue found in the animal's thighbone strongly suggests it was a female, and just about to lay eggs, the researchers report.
The bone tissue is strongly similar to that made inside the bones of female birds -- and no other living type of animal -- when they are producing the hard shells of eggs just before they lay them, said Mary Higby Schweitzer of North Carolina State University in Raleigh.
"In addition to demonstrating gender, it also links the reproductive physiology of dinosaurs to birds very closely. It indicates that dinosaurs produced and shelled their eggs much more like modern birds than like modern crocodiles," Schweitzer told reporters in a telephone briefing.
Female birds produce a layer of bone tissue called medullary bone when they are laying eggs. It is rich in calcium, providing minerals that would otherwise be leached from harder bone material, leaving the bird susceptible to fractures.
"The way that crocodiles lay and shell their eggs is they hold them in their reproductive tract and shell them all at once," Schweitzer said.
"Birds shell their eggs one at a time as they move down through the reproductive tract. It is a pretty calcium-intensive process."
ALREADY A STAR
This particular T. rex fossil made headlines in March when the same team of paleontologists reported it contained preserved soft tissue -- the first ever found in a dinosaur bone.
"The reason that we have found all the things in this one particular animal is this specimen was in a very remote part of Montana, in the Hell Creek formation," said Jack Horner of the Museum of the Rockies and Montana State University.
"It was so far out in the country that we needed to helicopter it out and we actually had to split the thighbone into two pieces to get it into the helicopter."
When Schweitzer unwrapped the cracked-open femur she immediately saw the soft tissue and went to work proving its remarkable state of preservation.
Horner plans to crack open some other bones.
"We have 12 specimens of Tyrannosaurus rex here at this institution, and we are about to find out if any more of them are females, just by looking inside," he said.
It was a stroke of luck to find an animal at just the right stage to be making medullary bone, Schweitzer said.
"It would not be present in a brooding animal," she said.
"But it would be present as long as there was an egg left to lay. The animal was probably near the end of its laying cycle."
Finding another such specimen will be difficult.
"I think it is pretty much a long shot," she said.
In April, Tamaki Sato of the Canadian Museum of Nature in Ottawa, and colleagues reported they had found the fossil of a dinosaur in China that carried two eggs in its body.
Its physiology also was closer to modern birds than to modern crocodiles, Sato reported.
Horner said most experts are convinced the two-legged dinosaurs known as theropods were closely related to living birds.
"This is another piece to the puzzle and there are a lot of them," he said. "Anyone who would argue that birds and dinosaurs are not related -- frankly I'd put them in the Flat Earth Society group."
Quite a few actually are convinced all birds are not necessarily descendants but are a branch of the dinosaur family that survived. It does seem believable when you look at their features and compare them to that of the extinct dinosaurs.
Any shot at getting this stuff radiocarbon dated? I know, I know, in theory it shouldn't radiocarbon date at all, but just for jollies.
Creationist/ID heads exploding in 5...4...3...2...1...
carbon14 dating is useless for that timeframe. IIRC, C14 dating's utility bottoms out at about 50,00 years, due to radioisotope depletion.
Radioisotopes of other elements... potassium?... allow for the dating of much older materials.
Well, I wouldn't be able to do much more than make an idle suggestion, but what would be the point? As you note, radiometric dating cannot be applied if the necessary isotopes aren't present..
Phooey, anaerobic bacteria would digest it in a heartbeat. The conditions must been really acid, basic or cold for it to last ansd somewhere the guy got autoclaved, preserving the tissue.
Could happen, I guess.
Why not?
P.S., Oxygen doesn't burn. I take it's been a long time since you took Chemistry.
Ah, but we already know from creation science statistics that when the odds against an event are "one in a million", the event is completely and totally impossible.
That's what it sounds like. This team had to deliberately crack a bone in half to get it on the helicopter and that unique "problem" gave them the opportunity to look inside.
BTW, the tissue wasn't soft at the outset, it had to be re-hydrated to become pliable.
IIRC, the YEC crowd has this novel notion that C14 dating is perfectly accurate right up to 6-10,000 years ago, and then suddenly becomes utterly bogus.
Oh really. Please share your insights on this absolute.
Won't change a thing. That mule's nose breaks 2x4s.
Nice to hear from you. I see being wrong hasn't hurt your sense of humor. (laughing as I type)
Riddle me this Batman.
How can the hemoglobin (red blood cells) not turn to dust in 68 million years?
Can some 'smart apple' out there get me the percentage of water in hemoglobin. That is the major component of the 'soft tissue' we are talking about?
Cripes!
Well -- it does solves the hazard of cloning 6 ton mosquitoes
;->
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