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."
|
Oxygen burns. Without oxygen the soft tissue would and could last forever; or until the end of the earth, whichever comes sooner.
two things:
1. "They" will maintain that dinosaur-to-bird is only "modification within Kind" - not evolution
2. does this mean that t.rex tastes like chicken?
I'd say it differently - anyone who believes Dinoaurs and birds are related based on this article must be a member of the flat-line society.
Oh yeah... I see.
Little brown dots in the "T-rex" tissue and Little brown dots in the Ostrich tissue = they are the same.
Does it for me. what other proof could we possibly ask for.
What're you talking about? Who's trying to suppress what story??
PS. I actually know the researcher who discovered the fossilized soft tissue.
Funny, we get those all the time here.
It's an amazing find.
If other paleontologists can reproduce & confirm this (they'll be reluctant to drill into bones in their precious collections), and if they can extract some usable DNA, and if this holds for earlier dinosaurs -- then we'll be in for some major changes in the Sauro-Aves cladistic chart.
Is this a statement of fact or faith?
In a completely anoxic environment in which temperatures remain nearly constant, there is no scientific reason I am aware of that soft tissue could not be preserved.
It would be a mistake to think that what has been left behind is anything like barely-decomposed animal tissue. This isn't like pulling a strip of preserved muscle from a dinosaur bone...
These are tiny separated "islands" of organic residue that were sealed so perfectly from necrotic agents that "something" other than rock or mineral was left over after all of these years.
It would be surprising to find intact DNA in these samples, but if they got that extraordinarily lucky, we'll know a lot more about dinosaurs in 10 years than we have learned in the previous 100.
But it's true, this story was suppressed! This fossil, along with the 100 mpg carburetor, the remains of Noah's Ark, and the Shroud of Turin, were all kept hidden away by those eeeeevvvviiillll scientists, who want to ... well, to do bad things.
</Highschool-dropout, workin'-in-the-sawmill mode>
acording to Bob Bacher chickens ARE little Dinosaurs
Is anyone else waiting to see a rib turn into a woman?
...play nice...
A vanishingly small probability. However, the soft tissue is made up of collagen, and probably other proteins as well. What's interesting is they successfully tested the tissue with something that reacts to chicken collagen:I am curious if there is any salvagable DNA, as well.
Would answer many questions.
By Menton's own formulation, birds should not be related to dinosaurs because "After all, dinosaurs are reptiles," and so he weakens his own position. Again, it is the "Supporting Online Material" that holds the even greater denunciation of Menton's creationism. It is there that we find that Schweitzer et al also prepared organic extracts from the MOR 1125 T. rex, encasing sandstone, and associated fossilized plants. They also prepared similar extracts of modern bird tissues, specifically ostrich bone, chicken bone, and chicken tendon. These extracts were tested by ELISA immunoassay against antisera for bovine osteocalcin, and chicken collagen. Osteocalcin is highly conserved (very little variation) across bony organisms, and it matters little which type is used (See Ancient Molecules and Modern Myths for further details). Not so for collagen. In the graph below, these data are summarized with negative controls from blanks, and buffers. The data have been adjusted to account for non-specific reactivity of the controls. Note also the dilution effects.
This graph is David Menton's nightmare; strong indication that there is molecular evidence that birds evolved from the dinosaurs. Notice that the two samples drawn from the fossilized femur MOR-1125 both show significant responses to x-Osteocalcin and x-chicken collagen, as do tissues from modern chickens and ostriches. Comparison to the burial matrix, and other controls that showed little to no reaction clearly demonstrates that there are protein fragments associated with the fossil bone. The ratio of collagen reaction to osteocalcin reaction contrasted between the dinosaur samples and the chicken tendon and chicken bone samples helps further fix these as bone derived protein fragments. Even though nearly every paleontologists alive feels that the fossil data relating birds and dinosaurs is already adequate, we could be looking at the molecular "smoking gun."
The potential significance of Schweitzer et al seemed totally over the head of Carl Wieland, who cheered this paper as "evidence" for a young Earth. Merton's desperate need to attack Schweitzer et al with such flatulence as, "One must assume that the standards for publication in even the most prestigious scientific journals like Science are quite different for evolution than for any other branch of empirical science," at least suggests that unlike Wieland, he is aware of the fact that this paper could presage the end of creationism's favorite argument that birds are unrelated to dinosaurs.
Cool! Ask her if she could repeat the test mentioned in post 36, only this time test it against reptile, amphibian, bird, & mammal collagen. This would provide a solid case for dinos being more related to birds than to other clades.
More like vulture.
oh, SPEEEWWWWWW!
buzzard stinks like... well... there ain't no polite word to describe the reek. I don't wanna imagine what it tastes like.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.