Not a Clue.

[Tidgy's Dad]

This specimen came to me via Sophie @fifbrindacier, @Coco and Santa. 

It is from the Eifelian, Middle Devonian of Col d'Aubisque, France and was labelled Calceola sandalina, which it clearly isn't, but may be a coral. 

Any ideas, anyone? It is sort of rectangular, widening upwards, but concave on each of the four sides. No signs of horizontal growth lines. 

Thank you,

Adam.

  

Reverse. 

'Narrow' sides :

Bottom - narrow end : 

Top - wide end :

 

[TqB]

Racking my brains here but I'm wondering if it's a cast/internal mould of a dissolved out favositid colony - there seem to be moulds of pores running between what would be the corallites. I've got a similar preservation in a Bolivian Pleurodictyum.

 

Close up of your first photo:

[Rockwood]

The way new coralites are inserted as the colony spreads seems a good match for a favositid as well.

[Coco]

Hi Tidgy's Dad,

 

I can't help you, but it is Col d'Aubisque. Sophie surely will help you

 

Coco

[Tidgy's Dad]

2 hours ago, Rockwood said:

The way new coralites are inserted as the colony spreads seems a good match for a favositid as well.

 

2 hours ago, TqB said:

Racking my brains here but I'm wondering if it's a cast/internal mould of a dissolved out favositid colony - there seem to be moulds of pores running between what would be the corallites. I've got a similar preservation in a Bolivian Pleurodictyum.

Thank you gentlemen, very helpful.

I have just found a photo from an earlier post by Sophie with the very same specimen plus a couple of others.

Some seem more rounded and another more squared off. 

[Tidgy's Dad]

And another one :

[FossilNerd]

Internal mold of a rugose coral? 

 

Image taken from here...

https://www.digitalatlasofancientlife.org/learn/cnidaria/anthozoa/rugosa/

[Tidgy's Dad]

1 hour ago, FossilNerd said:

Internal mold of a rugose coral? 

 

Image taken from here...

https://www.digitalatlasofancientlife.org/learn/cnidaria/anthozoa/rugosa/

I think you're right. 

Though those ones are Ordovician, they look very similar in some regards. 

[FossilNerd]

39 minutes ago, Tidgy's Dad said:

I think you're right. 

Though those ones are Ordovician, they look very similar in some regards. 

I thought so too. Maybe the ones that are more squared are simply ones that were compressed post mortem.

[Tidgy's Dad]

Maybe, but I doubt it, not this shape. 

I have found several corals with a similar structure if not shape. 

This one from the Brooks Range in Canada. (redundancydept.com) 

Or this Cyathophyllum from Europeana Collections. 

This also Cyathophyllum (Science Source) 

 

The genus can be squared off like this one from the BRSLI :

And also the genus does exist in polygonal, colonial form where the walls can curve inwards between corallites (from the Steinkern.de gallery):

 

So, could my specimen be the internal mold of a single corallite from a colonial rugose coral ? 

 

 

[FossilNerd]

1 hour ago, Tidgy's Dad said:

Maybe, but I doubt it, not this shape. 

I have found several corals with a similar structure if not shape. 

1 hour ago, Tidgy's Dad said:

So, could my specimen be the internal mold of a single corallite from a colonial rugose coral ?

Hmmmm... You may be right. My post mortem guess was geared towards some of them being round and others not. I was thinking they could all be the same genus/species and are diagnostically supposed to be round or round-ish. My first thought was that some of them may have been smushed. 

 

I like your idea better.  

[Rockwood]

3 hours ago, Tidgy's Dad said:

I have just found a photo from an earlier post by Sophie with the very same specimen plus a couple of others.

 

How did you end up with Sophie's specimen ?

 

2 hours ago, Tidgy's Dad said:

So, could my specimen be the internal mold of a single corallite from a colonial rugose coral ? 

No. I think the shape fits that of a tabulate colony much better. It is common for them to split along the wall lines. The shape need not even represent the entire colony. It could be just the lines of least resistance.

[Tidgy's Dad]

1 hour ago, Rockwood said:

How did you end up with Sophie's specimen ?

 

No. I think the shape fits that of a tabulate colony much better. It is common for them to split along the wall lines. The shape need not even represent the entire colony. It could be just the lines of least resistance.

Sophie must have sent it to Coco. 

Santa stole it and gave it to me for Christmas. 

[Rockwood]

4 minutes ago, Tidgy's Dad said:

Sophie must have sent it to Coco. 

Santa stole it and gave it to me for Christmas. 

Ah! That 'splains it. 

[TqB]

I'm happy with the short circular ones probably being rugose moulds, but, like @Rockwood, I think the square ones are probably tabulate with the same preservation.

[Coco]

Hi,

 

On 06/02/2020 at 3:18 AM, Tidgy's Dad said:

Sophie must have sent it to Coco. 

Santa stole it and gave it to me for Christmas. 

Correct Sherlock Holmes !

 

Coco