Double Shell Dino Egg? Weird Titanosaur Egg Shell Fragment

[jikohr]

Hi everyone!

 

I acquired some Titanosaur eggshell fragments from Patagonia, Argentina recently and a few stood out as being weirdly thick. Looking at the side it looks like they consist of two shells fused together.

 

I tried to find something similar among other dinosaur egg fossils to no avail. Among modern birds however, specifically chickens, this is know to happen when an egg gets pushed back up inside instead of being laid and another shell forms around it, called "double-shelled eggs".

 

Is that what this is? Has that ever been documented in dinosaurs before? Any insight is appreciated as always!

 

One side of the shell is polished so I included a microscope shot of it and an unpolished side, as well as microscope shots of the shell texture. The piece measures 47.5 x 40 x 10 mm.

 

[Mahnmut]

Hi Jikohr,

fascinating pieces.

I just read a bit about double shelled eggs in poultry, which I guess you will also have done.

https://www.sciencedirect.com/science/article/pii/S0032579119528917

http://www.poultryhelp.com/oddeggs.html

 

It seems to me in none of the modern cases described in the sources above the two layers of shell where directly merged, there where always membranes and some fluid (albumen) in between as far as I understood it. Your specimens at least look as if a layer of mineral shell had been deposited directly above another one. Could be taphonomy ?

That is only the result of me reading 10 minutes worth of chicken tales, but seems to be a slightly different story in comparison to your fossils.

Still I think what can happen in fowl can happen in Dinos, but maybe not exactly that way...

Just my thoughts.

Curious ro hear more.

Best regards,
J

[Mahnmut]

47 minutes ago, jikohr said:

 

 

I just took a closer look at your fotos, especially the ones above.

Actually I do not even know enough about egg fine structure to be sure that there arent always two layers that just got more obvious in thicker shells, why ever they where thicker.

To me it clearly looks as if the thinner layer was growing in continuation of the thicker one. That would be a point against membranes inbetween, so against being a direct analogue of the double shelled chicken eggs. I wonder if its rather a case of disturbed growth, due to stress, hunger...

Epitaxy could explain the chrystals growing on where they stopped after an interruption.

Still intrigueing.

May I kindly ask @CBchiefski for his opinion after the enlightening insights he brought to another question recently?

Best regards,

J

J

Edited October 28 by Mahnmut
typo

[jikohr]

Just now, Mahnmut said:

I just took a closer look at your fotos, especially the ones above.

Actually I do not even know enough about egg fine structure to be sure that there arent always two layers that just got more obvious in thicker shells, why ever they where thicker.

To me it clearly looks as if the thinner layer was growing in continuation of the thicker one. That would be a point against membranes inbetween, so against being a direct analogue of the double shelled chicken eggs. I wonder if its rather a case of disturbed growth, due to stress, hunger...

Epitaxy could explain the chrystals growing on where they stopped after an interruption.

Still intrigueing.

May I kindly ask @CBchiefski for his opinion after the enlightening iinsights he brought to another question recently?

Best regards,

J

J

That would be fantastic, thank you!

Yeah my guess was also that the shells were fused by mineralization during fossilization. I've seen Titanosaur eggs posted on the forum that have agate form inside of them (and be IDed as eggs by members, I made sure to weed out the round rocks that get posted while researching) and thought maybe it was a similar process.

 

In the meantime, here's a microscope shot of the side of another Titanosaur egg fragment from the same locality but with just one layer which is the standard for these. This one measure 6 mm thick.

[Mahnmut]

I repeat, I do know close to nothing about eggs, its just my impression of what I see in the pics.

Lets hear the eggsperts.

[Randyw]

It is quite possible these are double shelled titanosaur eggs. There have been several found. If you go to google scholar and type in “double shelled titanosaur eggs” it will link to to several articles discussing them.

there were no reported ones until some were found in India. Since then there has been a few more describedsome even from Argentina . This link mentions them unfortunatly all except the abstract is paywalled. But there are others

https://www.tandfonline.com/doi/abs/10.1671/0272-4634(2004)024[0913%3AAMTDSE]2.0.CO%3B2

great pieces to add to you collection! I’m 

Edited October 28 by Randyw
Added link

[Josesaurus rex]

@jikohr-sanHello. This paper is about the phenomenon of multilayered eggs. I hope it helps you.
 

https://eas2.unl.edu/~dloope/pdf/JacksonSVP.pdf

[jikohr]

1 hour ago, Randyw said:

It is quite possible these are double shelled titanosaur eggs. There have been several found. If you go to google scholar and type in “double shelled titanosaur eggs” it will link to to several articles discussing them.

there were no reported ones until some were found in India. Since then there has been a few more describedsome even from Argentina . This link mentions them unfortunatly all except the abstract is paywalled. But there are others

https://www.tandfonline.com/doi/abs/10.1671/0272-4634(2004)024[0913%3AAMTDSE]2.0.CO%3B2

great pieces to add to you collection! I’m 

 

1 hour ago, Josesaurus rex said:

@jikohr-sanHello. This paper is about the phenomenon of multilayered eggs. I hope it helps you.
 

https://eas2.unl.edu/~dloope/pdf/JacksonSVP.pdf

Those are perfect, Thanks!

After I read up on them I'll post a summary of what the papers say about these.