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Peat Burns

Silica Formation Clam

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Peat Burns

I've been finding some interesting clam fragments at Paulding, Ohio (Silica Fm., Middle Devonian) with original shell and a conspicuous sharp angle along the dorsal side of the shells.  They are coming from the limestone layers of the formation (not the shale).  Finally, I got one complete enough that I might be able to get an ID.  It's about 3/4 complete, but unfortunately it's missing the anterior end, including the umbo.  I've tried to illustrate the shape via some photos with reconstructions (red line) of what's missing.  It's hard to illustrate the 3D qualities with photos.  I'm thinking this is Mytilarca cordata. Looking for confirmation from those familiar with clams of Silica Formation or other Devonian formations of same age.  The shell (what remains of it) is about 6cm in length.

@crinus

20180808_004641.thumb.png.49b8c68f6ee4f06eb3745980c1dc1912.png

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Peat Burns

20180808_002200.thumb.jpg.ad815121c7ed63ad3b54e90b1ff4cbff.jpg

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Innocentx

These are very well preserved for their age, periostracum and all. Is possibly missing diagnostic features?

Hope you get ID for these.

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Peat Burns
43 minutes ago, Innocentx said:

These are very well preserved for their age, periostracum and all. Is possibly missing diagnostic features?

Hope you get ID for these.

Yeah, the shell is beautiful. I was very happy with this find, it's hard to get clams there that are more than small broken fragments.  Luckily most of this one was still embedded in the limestone where it was protected. I exposed it with the air scribe.

 

Based on the triangular morphology, I *think* it narrows it down to Mytilarca cordata. I know that taxon has been recorded at Paulding.  It was first described in 1933 from specimens from the Silica Fm. of Ohio.:)

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Peat Burns
4 hours ago, crinus said:

Yes it is Mytilarca cordata.  Here is the one I found at Paulding.  It is in the shale and not the limestone.

http://www.crinus.info/mollusks/data/myt.htm

Thanks, Joe.  Much appreciated. Is more of yours exposed on the other side, or is it compressed in the matrix?

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crinus
3 hours ago, Peat Burns said:

Thanks, Joe.  Much appreciated. Is more of yours exposed on the other side, or is it compressed in the matrix?

Mine actually is free of the matrix and 3D.   I just put it back on the matrix for the  photo.  I, in general prefer matrix specimens.   I keep the matrix because it makes for a better display.

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Peat Burns
34 minutes ago, crinus said:

Mine actually is free of the matrix and 3D.   I just put it back on the matrix for the  photo.  I, in general prefer matrix specimens.   I keep the matrix because it makes for a better display.

If you ever get a chance someday, I'd love to see a picture of the other side.  I think your photo on the FUMMP database and your website are the only photos available for that species on Google search.

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crinus
On 8/9/2018 at 11:07 PM, Peat Burns said:

If you ever get a chance someday, I'd love to see a picture of the other side.  I think your photo on the FUMMP database and your website are the only photos available for that species on Google search.

@Peat BurnsHere is the photo of the other side.  There has been no prep work done to the other side.

DSC_0282.JPG

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Peat Burns

Thank you, Joe.  Much appreciated.   Beautiful specimen.

 

Tony

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