Brachiopods at Paulding, OH from micro matrix

[Acryzona]

I've been posting identified microfossil fauna I've found at the Middle Devonian site in Paulding, OH on separate thread.  However I've found a number of immature(?) brachiopods in my washings that I'd appreciate ideas of their genus / species designation.  Tagging @Peat Burns and @ClearLake as they collect at Paulding.  I'll post different specimens (there's a few) as I get photos taken.  Here is the first photo.  

[ClearLake]

@Acryzona, sorry for the delayed response.  I finally remembered your post when I found a similar looking brachiopod picking out of my 40 mesh sieve.  Is there anything visible on the hinge line of yours?  That might help in narrowing it down.  My first thought is a Paraspirifer based on the general shape, ribbing and what I think I see as the start of a fold/sulcus and of course they are quite common in the Silica.  I'll have to see if I can find anything on the growth of some of these forms to see if very tiny ones have been illustrated.  I think @Tidgy's Dad is back in action, I wonder if he has any thoughts.

[Tidgy's Dad]

My thoughts are mainly about sleeping and cheese at the moment. 

The size of the juvenile, the style of ribbing in the sulcus and the fact that this shell has its widest point along the midline and not the hingeline , suggest to me that this is more likely an orthid than a spiriferid, though I'm not entirely certain from this one image. 

The only orthid that Tony has listed from Spaulding is Schizophoria ferronensis and this is not that. 

I would guess the adult is a very small orthid.  

[TheInvertebrateGuy]

To me, it looks like a brachipod from the suborder Dalmanellidina.

[ClearLake]

14 hours ago, Tidgy's Dad said:

The only orthid that Tony has listed from Spaulding is Schizophoria ferronensis and this is not that. 

I would guess the adult is a very small orthid.  

In their book on Silica fauna, Kesling and  Chilman list 8 Orthid species in four genera: Schizophoria, Sphenophragmus,  and Tropidoleptus.  The one that seems like a possible match is Sphenophragmus cf. nanus which is described as rare but where it does occur it I’d found as a small brachiopod from 0.1 - 6 mm.   The problem is the diagrams in the book are equally small and my eyes can’t discern if the details match the specimen figured above.  Pictures of this species I see on the web look like they have much finer costae than the specimen in question as do most dalmanellids that I am familiar with, but there could be a match out there. Tropidoleptus has coarser costae, but the shape seems wrong for the specimen in question. 

[Tidgy's Dad]

1 hour ago, ClearLake said:

In their book on Silica fauna, Kesling and  Chilman list 8 Orthid species in four genera: Schizophoria, Sphenophragmus,  and Tropidoleptus.  The one that seems like a possible match is Sphenophragmus cf. nanus which is described as rare but where it does occur it I’d found as a small brachiopod from 0.1 - 6 mm.   The problem is the diagrams in the book are equally small and my eyes can’t discern if the details match the specimen figured above.  Pictures of this species I see on the web look like they have much finer costae than the specimen in question as do most dalmanellids that I am familiar with, but there could be a match out there. Tropidoleptus has coarser costae, but the shape seems wrong for the specimen in question. 

Sphenophragmus is plano-convex and this specimen doesn't appear to be. Not sure if we can have a shot of the other side @Acryzona? It also seems to have more closely spaced and numerous ribs  and is parvicostellate. 

The enigmatic Tropidoleptus may be a closer match as sometimes it does have a greater width across the middle than the hingeline. But how coarse are the ribs in the OPs specimen? Some look quite broad. Maybe. Nobody seems quite certain whether Tropidoleptus is an orthid or a strophomenid at the moment. 

You mentioned four genera? 

[ClearLake]

52 minutes ago, Tidgy's Dad said:

 

You mentioned four genera? 

For some reason during my editing of my comment the genus Riphidomella was erased. 

[Tidgy's Dad]

9 hours ago, ClearLake said:

For some reason during my editing of my comment the genus Riphidomella was erased. 

Well, I'm pretty certain it isn't Rhipidomella, so I might be leaning toward Sphenophragmus at the moment. 

[Acryzona]

Thank you all for your comments and thoughts.  I’m learning from your posts though I’m scrambling for dictionary!  

 

I am currently photographing the other side of this specimen and then I will photograph the hinge.  Stay tuned…

[Acryzona]

Below are photos of the other side and the hinge of brachiopod "A" .  To me, the hinge looks damaged but am posting the image of completeness.  I have a few other specimens that look like brachiopod "A" which might have a better hinge but I didn't want to confuse the issue by posting photos from two different specimens at the moment.

 

 

Edited July 10, 2022 by Acryzona