My best guess is Sowerbyella ?

[Denis Arcand]

Hi,

 

I am still new at identifying brachiopods, I know there is a great diversity of similar species, which makes it even more difficult for me.

Can you help me identify these two brachiopods, they both feature a semicircular outline, concavo-convex profile, and small size (~1.0 cm wide). They also have a wide, straight hinge numerous and very fine lines and ribs.

 

Not sure if they are the same species, one of them has a larger size with a bit smaller width compared to length. So I don't think they are the same species.

 

The plate was found in the Nicolet River Formation south of Montreal, QC

 

Any help would be appreciated, thanks !

 

Edited Saturday at 12:12 AM by Denis Arcand

[Mark Kmiecik]

I can't help with ID, but that is a beautiful hash plate.

[Tidgy's Dad]

Both Sowerbyella sericea, I would think. It's quite a variable species.  

Edited Saturday at 12:21 AM by Tidgy's Dad

[Fossildude19]

14 minutes ago, Tidgy's Dad said:

Both Sowerbyella sericea, I would think. It's quite a variable species.  

 

 

Hmm. I would think the lighter one would be a Strophomenid, either Strophomena sp. or Rafinesquina sp. ???

 

[Tidgy's Dad]

Yes. 

Thanks, Tim. 

Strophomena has a concave brachial valve and a convex pedicle valve. Rafinesquina has the reverse. 

This valve is convex and also has pointed cardinal extremities, I'm not sure if it's a brachial or pedicle valve. Maybe that's an erosion exposed part of the sealed over pedicle foramen visible at the centre of the posterior margin? (adult strophomenids don't have a pedicle opening) 

If so, it maybe Strophomena sp. with S. huronensis a possible candidate.

 

[Denis Arcand]

 

Great, not only do I get free IDs , but you also give me great clues on how to tell the different species apart. This is exactly what I need, I always have a hard time telling brachiopods apart, because a lot of them look alike (at least for me) and I always have a hard time finding that kind of clue on the internet, and with the name that you gave me I can refine my search.

 

Thank you very much @Tidgy's Dad and @Fossildude19 for your help in identifying my little find. 

 

I will surely ask for other brachiopod identifications when time permits 

Edited Tuesday at 11:20 AM by Denis Arcand