Leighton Formation Fossil ID - Brachiopod?

[Mainefossils]

I have just found this microfossil. It is unfortunately incomplete, but the general shape is still discernible. I have two ideas for this specimen, a fish scale or an inarticulate brachiopod. Of these possibilities, I think that inarticulate brachiopod is more probable. The shape, "growth rings", and slight depression in the top lead me to this conclusion. On the other hand, its size, color, and the absence of such brachiopods from this formation, lead me towards fish scale. I am uncertain on both, and could use some help with this one.

 

The specimen is the from the Leighton Formation, Maine; it is Pridoli, Silurian. 

 

Thanks everyone for your time! 

 

[Tidgy's Dad]

Well, it looks like a brachiopod to me. Discinid, perhaps? 

[Mainefossils]

Thanks for your opinion! I guess that this little brachiopod is just one of the first seen from this formation. Thanks for your time! 

[Fossildude19]

Brachiopod gets my vote as well. 

[Mainefossils]

So, I have just found a listing of many of the species found in this formation. The genus Orbiculoidea is found in this formation, specifically the species O. rugosa. Unfortunately, I have not been able to find any other records or papers on this species. The plate below shows the type species, O. forbesii in figures N - U. 

 

                                                          

 

Mergl, M. (2010) A review of Silurian discinoid brachiopods from Gotland, Sweden. Bulletin of Geosciences 85(3). 

http://www.geology.cz/bulletin/fulltext/1176_mergl.pdf