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Brachiopod ID, + Bryozoan?


Sinosauropteryx prima

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Hello all. I'm an amateur fossil hunter, so this might not seem that exciting, but I was really happy to find these four rocks with what I assume are brachiopods in them. These were found on a small, rocky beach in western Michigan (so rocky that most people would probably prefer not to swim). The specimens vary in size quite a bit, with the largest one being about 2 cm (this one is also one of the most well-preserved). In one of the rocks I see some lacy-looking material which I believe is probably a bryozoan frond, but I'm not too sure, so if anyone could confirm that too, I'd appreciate it. In the last few pictures, I wet a couple of the specimens themselves to hopefully make them easier to see. I hope these pics are good enough. If anyone could give me info on what exactly these little guys are, it would be greatly appreciated.

 

Thanks!

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Yes, brachiopods and bryozoans. 

The brachiopods are probably productids, but could be atrypids, can't tell for sure. 

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31 minutes ago, Tidgy's Dad said:

Yes, brachiopods and bryozoans. 

The brachiopods are probably productids, but could be atrypids, can't tell for sure. 

Thank you! I actually found another brachiopod a few feet from these guys which I thought looked like an atrypid. I was planning on posting it too. It was quite a bit bigger than these guys though, so not sure.

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Nice.  Are you over in the Manistee or Traverse City area of Mich by chance?  The brachs look like Devonian Atrypids (Atrypa, Pseudoatrypa).

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1 hour ago, Bob Saunders said:

Very nice, welcome from the South Haven area. 

 

Thank you!

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59 minutes ago, Peat Burns said:

Nice.  Are you over in the Manistee or Traverse City area of Mich by chance?  The brachs look like Devonian Atrypids (Atrypa, Pseudoatrypa).

I am! Are those genera common around here? Thanks bunches!

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38 minutes ago, Sinosauropteryx prima said:

I am! Are those genera common around here? Thanks bunches!

There are some substantial Devonian deposits over there.  The group of Middle Devonian formations found there and elsewhere in the state is called the Traverse Group.  Ellsworth and Antrim Shales are in that area as well.  Your finds would be common to many of those formations.  Go through that material with a "fine tooth comb", there ought to be a lot of goodies in there, including trilobites. Try splitting some of the Shale (with appropriate safety gear), if you find any, too.  The material you posted looks like it might be limestone.

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4 minutes ago, Peat Burns said:

There are some substantial Devonian deposits over there.  The group of Middle Devonian formations found there and elsewhere in the state is called the Traverse Group.  Ellsworth and Antrim Shales are in that area as well.  Your finds would be common to many of those formations.  Go through that material with a "fine tooth comb", there ought to be a lot of goodies in there, including trilobites. Try splitting some of it (with appropriate safety gear), too.

Ah yes, usually I just find little corals and crinoid stems, and this is the first time I've found a brachiopod, let alone a whole bunch of them, since I'm pretty new to the hobby. I'll definitely keep that in mind! Just from a quick search, Pseudoatrypa looks pretty accurate. Thanks for all the info!

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4 minutes ago, Sinosauropteryx prima said:

Ah yes, usually I just find little corals and crinoid stems, and this is the first time I've found a brachiopod, let alone a whole bunch of them, since I'm pretty new to the hobby. I'll definitely keep that in mind! Just from a quick search, Pseudoatrypa looks pretty accurate. Thanks for all the info!

My pleasure.  I agree on the Pseudoatrypa based on the height of the shell.  Atrypa are typically less highly domed. Pseudoatrypa is definitely one of my all-time favorites. 

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10 minutes ago, Peat Burns said:

My pleasure.  I agree on the Pseudoatrypa based on the height of the shell.  Atrypa are typically less highly domed. Pseudoatrypa is definitely one of my all-time favorites. 

It might become mine too! I actually found a slightly larger, singular brachiopod a few feet away from these guys, and I was planning on posting it tomorrow; I mention this because when I saw it, my first thought was that it looked like an Atrypa. Would you agree?

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9 minutes ago, Sinosauropteryx prima said:

It might become mine too! I actually found a slightly larger, singular brachiopod a few feet away from these guys, and I was planning on posting it tomorrow; I mention this because when I saw it, my first thought was that it looked like an Atrypa. Would you agree?

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Definitely another Atrypid.  Hard to say genus.  Side view would help (to show height of "dome")

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4 minutes ago, Peat Burns said:

Definitely another Atrypid.  Hard to say genus.  Side view would help (to show height of "dome")

Sure thing; here are the side views.

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3 hours ago, Sinosauropteryx prima said:

Sure thing; here are the side views.

 

 

It has a profile and shape like Atrypa, but I can't rule out Pseudoatrypa.  There is some overlap in the profiles of the two species, and sometimes profiles can be deformed from taphonomic processes.  The valves of Pseudoatrypa tend to be more elliptic in outline, whereas Atrypa tend to be more circular (like yours), but again, there can be overlap between the two.  Beyond that, details of the interior and hinge are required for definitive determination.  I'd label it as "aff. Atrypa sp."  Compare with Atrypa reticularis.

 

 @Tidgy's Dad, what do you think?

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I agree, Tony, the morphology within these two genera can be extremely variable and sometimes overlap, as you say. In the treatise it states that the difference is said to be the thick pedicle callist in Atrypa compared to a minimal pedicle callist in Pdeudoatrypa. 

IPKBase Beta 2

(image from the University of Kentucky database) .

With this specimen (and the earlier ones posted), it's impossible to tell and, though I too would lean towards Atrypa, I concur that it's probably safe to assign it to the family Atrypidae, but nothing certain beyond this. 

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Tortoise Friend.

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40 minutes ago, Peat Burns said:

It has a profile and shape like Atrypa, but I can't rule out Pseudoatrypa.  There is some overlap in the profiles of the two species, and sometimes profiles can be deformed from taphonomic processes.  The valves of Pseudoatrypa tend to be more elliptic in outline, whereas Atrypa tend to be more circular (like yours), but again, there can be overlap between the two.  Beyond that, details of the interior and hinge are required for definitive determination.  I'd label it as "aff. Atrypa sp."  Compare with Atrypa reticularis.

 

 @Tidgy's Dad, what do you think?

 

18 minutes ago, Tidgy's Dad said:

I agree, Tony, the morphology within these two genera can be extremely variable and sometimes overlap, as you say. In the treatise it states that the difference is said to be the thick pedicle callist in Atrypa compared to a minimal pedicle callist in Pdeudoatrypa. 

IPKBase Beta 2

(image from the University of Kentucky database) .

With this specimen (and the earlier ones posted), it's impossible to tell and, though I too would lean towards Atrypa, I concur that it's probably safe to assign it to the family Atrypidae, but nothing certain beyond this. 

Thank you guys for your help!

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