Odd shape Lampshell

[DE&i]

 

 

I’m going to try and i.d. these Silurian brachiopods, as this note in the matchbox below that holds them is all the information I have.

 

 

What I have noticed is those indicated with the “white arrow” below would appear to have the same appearance as each other.

But the one indicated by the “red arrow” below looks more bulbous and not flat on the bottom.

 

 

Does anyone think that there may be two different species here?  

 

WHITE arrowed brachiopod below:

Bottom view

 

 

Top view 

 

 

Front view

 

 

 

RED arrowed brachiopod below:

Top view

 

 

Bottom view

 

 

Front view

 

 

 

 

 

[westcoast]

Probably all Atrypa, possibly Atrypa reticularis. However there are other atrypids and internal details may be required for confident identification. There is a publication by Paul Copper that gives a lot of detail.

[DE&i]

6 minutes ago, westcoast said:

Probably all Atrypa, possibly Atrypa reticularis. However there are other atrypids and internal details may be required for confident identification. There is a publication by Paul Copper that gives a lot of detail.

 

Thank you @westcoast i'll see if I can track the publication down as a PDF. 

[Taogan]

Atrypa are fairly variable, I have a box of about 200 and they all look slightly different.