Small items on a brachiopod shell

[KCMOfossil]

In the Winterset Limestone of the Kansas City Group (Pennsylvanian) there is a section that is thick with Composita brachiopods.  On one of these I found the tiny (around 1 mm) items in the pictures.  Any help with their identification would be appreciated. 

Russ 

 

 

[KCMOfossil]

[FossilDAWG]

Traditionally these small coiled attached shells have been identified as Spirobis, a polychaete worm.  More recently, studies of the shell microstructure suggests that these are only superficially similar to Spirobis, and they actually belong to the Microconchida, an extinct order possibly related to the lophophorates.

 

Nice specimen!

 

Don

[KCMOfossil]

7 minutes ago, FossilDAWG said:

Microconchida, an extinct order possibly related to the lophophorates.

 

 

Very interesting, Don.  This is definitely new to me.  I hope to read more about it this evening.  My only guess was some sort of tiny ammonoid, but I was puzzled by the worm-like appearance.

 

Russ 

[doushantuo]

Let me state cryptically that googling Spirobis will not get you any taxon.

Notice how i DON'T put Spirobis in italics

However,Don's link is excellent.

[TqB]

That is an excellent paper - I've seen hundreds of those things in the Coal Measures around where I live. (From the paper, it's also news to me that Hederella is a problematicum...)

 

Good specimen too!

 

 

[Plantguy]

Great find. Interesting thread. Regards, Chris 

[Max-fossils]

Obviously, it's not this, but am I the only one to whom those critters remind me of the small Aconoceras ammonites?

Here is a pyritized Aconoceras nisus from my collection (they come from Carniol, France, and date from the early Cretaceous) (sorry for bad quality, this pic is highly cropped).

 

 

Btw, nice fossil!

[abyssunder]

Spirorbis

[KCMOfossil]

On 7/9/2017 at 2:00 PM, Max-fossils said:

those critters remind me of the small Aconoceras ammonites

They are very similar.  I wonder if this would be considered another example of convergent evolution such as that pointed at by the article Don linked to.

 

Thanks for the input and the picture.

[Max-fossils]

18 hours ago, KCMOfossil said:

They are very similar.  I wonder if this would be considered another example of convergent evolution such as that pointed at by the article Don linked to.

 

Thanks for the input and the picture.

Could be 

[Virgilian]

Deleted.

[Coco]

On 12/07/2017 at 1:10 AM, Virgilian said:

Supprimé.

Why ?

 

Coco