Quick Trilobite ID?

[kerouac22]

Hey guys,

This is my first and only trilobite, which I found earlier this year in a creek bed in Missouri. The rocks in that area are predominately Mississippian or Pennsylvanian, but this particular creek seems older, maybe Devonian.

I'm new to all this, so take all that with a grain of salt.

So what do you all think?

[kerouac22]

And here's a scale reference. I should mention that I found it weathered out of the rock already, just as you see it here (no prep). Thanks!

[Slowpoker]

Hmm...

I'll take a blind stab and say Phacops, though I am very likely to be wrong.

[howard_l]

I am guessing Carboniferous, maybe Pennsylvanian. All the trilobites I have found including Mississippian, I have never found a Pennsylvanian one.

[howard_l]

Are there other fossils there, that might help in determining the age.

[piranha]

It's definitely not a phacopid. This lower Mississippian phillipsiid trilobite is a good match with: Comptonaspis swallowi

[piranha]

Some good references:

 

Brezinski, D.K. (1986)

Trilobite associations from the Chouteau Formation (Kinderhookian) of central Missouri.

Journal of Paleontology, 60(4):870-881

 

Brezinski, D.K. (1988)

Revision and redescription of some Lower Mississippian trilobites from the Chouteau Formation (Kinderhookian) of central Missouri.

Journal of Paleontology, 62(1):103-110

 

Brezinski, D.K. (2000)

New Lower Mississippian trilobites from the Chouteau Group of Missouri.

Annals of Carnegie Museum, 69(2):135-144

 

 

 

[kerouac22]

It's definitely not a phacopid. This lower Mississippian phillipsiid trilobite is a good match with: Comptonaspis swallowi

IMG1.jpg

Some good references:

Brezinski, D.K. (1986)

Trilobite associations from the Chouteau Formation (Kinderhookian) of central Missouri.

Journal of Paleontology, 60(4):870-881

Brezinski, D.K. (1988)

Revision and redescription of some Lower Mississippian trilobites from the Chouteau Formation (Kinderhookian) of central Missouri.

Journal of Paleontology, 62(1):103-110

Brezinski, D.K. (2000)

New Lower Mississippian trilobites from the Chouteau Group of Missouri.

Annals of Carnegie Museum, 69(2):135-144

Looks like you're onto something there. The glabellas, in particular, are very similar.

Thanks, and thanks for the references as well.

[kerouac22]

Are there other fossils there, that might help in determining the age.

Here's an image of a couple types of weather-worn brachiopods I find around there. The type on the right is much more abundant than the other.

[Slowpoker]

It's definitely not a phacopid. This lower Mississippian phillipsiid trilobite is a good match with: Comptonaspis swallowi

IMG1.jpg

Ah yes, I knew it would not be,

Excuse my incompetence, I'm not good at Identifying anything other than dinosaur or marine reptiles, just wanted to help out.

Good luck nevertheless!