Apr
17
2005

Dinosaur eggs found inside mother's skeleton

Scientists in China have discovered a fossil dinosaur skeleton with unhatched eggs inside. Though fossil dino eggs have been known for decades, this is the first time eggs have ever been found still inside the mother's body.

The fossil has two eggs, about the size of pineapples, one for each ovary (the part of an animal's body that produces eggs). The discovery is seen as more evidence of the link between crocodiles, dinosaurs and birds.

  • Crocodiles are very primitive reptiles. They have two ovaries, each of which can produce many eggs.
  • Dinosaurs evolved from crocodile-like ancestors. The newly-discovered dinosaur also has two ovaries, but each produces only one egg at a time.
  • Birds, which descended from dinosaurs, have only one ovary. But like the dinosaur, bird ovaries also produce only one egg at a time.

So, this dinosaur's egg-laying system seems to be about half-way between crocodiles and birds -- pretty much what we would expect, given the sequence in which these animals evolved.

Your Comments, Thoughts, Questions, Ideas

Dave's picture
Dave says:

Dinosaurs have more in common with reptiles than they do with birds.

posted on Fri, 07/15/2005 - 4:57pm
Gene's picture
Gene says:

True. But birds have more in common with dinosaurs than with any other group of animals, living or extinct.

Think of it this way: dinosaurs are a subset of reptiles, and birds are a subset of dinosaurs.

posted on Sun, 10/02/2005 - 9:41pm
Anonymous's picture
Anonymous says:

Just because genes of animals are similar does not make them the same type. humans and watermelon are as much 95% the same (percentages go as high as 97%), yet we all would agree we are not related to watermelon.
Just because an animal does something ALMOST like another animal does not mean it descended from the other animal. There are too many things that are similar to each other genetically, yet unrelated to each other in scientific categories to make a claim like that.

posted on Wed, 11/02/2005 - 2:56pm
Gene's picture
Gene says:

I have never heard the claim that humans share 95% of their genes with watermelons. Do you have a cite? This article from Science magazine states humans share 99% of their genes with chimnpanzees, and about 10% with fruit flies. I imagine the percentage shared with watermelons is even lower, though not zero. Humans are related to watermelons, by the fact that all lviing things are related to one another. But our last common ancestor was well over half a billion years ago, so there is very little similarity left.

(You may have heard the old red herring: a watermelon is 97% water, and a cloud is 99% water, so they must be related! This is a misrepresentation of evolution. Relationships are determined by how many genes two animals have in common, not by how much water they have in common. Clouds have no genes, so they are not related to any animal.)

The only known way to get genes is to inherit them from your ancestors. My brother and I have a lot of genes in common, since we share a direct ancestor -- our parents. My cousin and I, however, do not share quite as many genes, since our last common ancestor was a little further back -- our grandparents. Humans share a great many genes with chimpanzes. The only known explanation is that we inherited them from a common ancestor about 5 million years ago.

If two animals are similar genetically then they are related. Science is constantly redefining its categories to better reflect evolutionary history, as our understanding of evolution grows better and more complete.

Yes, sometimes two animals that are not very closely related will independently come up with similar behaviors. So, behavior alone is not proof of a close relationship. However, if two animals have a lot of genes in common, and a lot of body parts (which come from genes) in common, then similar behavior can be seen as yet another indication of their relationship.

posted on Wed, 11/02/2005 - 3:36pm
Anonymous's picture
Anonymous says:

think of the size of those omelets!

posted on Thu, 11/10/2005 - 6:55pm
Anonymous's picture
Anonymous says:

Are they heavy to the people that find them? I would not go close to one of them things?

posted on Thu, 01/05/2006 - 3:08pm
bryan kennedy's picture

Yes, they would be heavy. The organic parts of the egg have been replaced by minerals that are more dense (and more heavy).

You probably don't have too much to worry about going close to them. They have as much chance of harming you as any old rock you find on the side of the road.

posted on Fri, 01/06/2006 - 9:22am
Anonymous's picture
Anonymous says:

National Geographic reported that humans and chimpanzees share only about 95% of their genes, recently revised from 98.5%.

posted on Tue, 05/22/2007 - 12:41pm
Gene's picture
Gene says:

Interesting. Can you post a link? Thanks!

posted on Tue, 05/22/2007 - 1:47pm

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