Mystery fossil

[DINOMAN91]

Came across this weird item on our favorite site labeled as an egg.

I’m thinking it could be a concretion, but there one part near the bottom that looks to have a piece of “shell” with texture.

In the other broken open one there’s a close up that looks like whiteish ribs or possible feather?

Can someone please help?

 

[DINOMAN91]

Here’s some other photos of the “shell” textured spot

[Rockwood]

Concretion. Looks like a piece of shell in one. It's common to see them in concretions.

[DINOMAN91]

Rockwood thanks so much for your input

[Mahnmut]

Hello Dinoman,

reminds me of what is relatively often offered as "ophidienovum" (snake eggs). They are supposed to be relatively common (for fossil eggs) in some regions of France for example. I bought one myself some time ago, trusting its description. I did not find much scientific information though.

If this was an egg, the rib- or featherlike structure would be very interesting indeed.

Best regards,

J

 

[Rockwood]

1 hour ago, Mahnmut said:

I bought one myself some time ago, trusting its description.

Just wondering. Has the trust aged well ?

[Mahnmut]

Relatively, yes.

here is another thread on a certain forum...

 

[pachy-pleuro-whatnot-odon]

With respect to the example @Mahnmut posted above, those are indeed considered to be snake eggs - although some discussion has more recently arisen as to whether these may not be wasp or other insect pupa, as they are sometimes found in the infill of the larger crocodile eggs. These "eggs" are encountered both in hollow calcified form, as described in said post, or as a crust around an infill (which is more common). In the right layers, they are indeed relatively common and one can find a couple dozen in a day's work.

 

Source of image of horse-fly pupae

 

 

 

 

 

 

 

 

 

 

 

As to OP's specimen: this doesn't look the right shape for ophidienovum. However, I also don't think this a concretion necessarily, but rather seems to be a steinkern, the internal mould of a fossil that once used to be. As to what fossil the mould would be from, for that we'd need more information about geological age and provenance. Notwithstanding, I do feel that the bit of supposed shell adhering to the steinkern has the right calcitic alignment for it to be candidate eggshell. Other eggsperts on this forum might be able to confirm or deny this.

 

Whatever the case, though, this fossil will never be more than the internal mould of an egg - that is, never the egg itself. As to the second, halved inclusion: could be another specimen similar to the main one, but could also be something entirely different. Hard to say with any measure of certainty...