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Huge calymenid cephalon!


andyrice11

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I've been finding some very large calymenid cephala from my usual Liston Creek limestone spot. Today, i found the biggest one I've ever seen. Ive also noticed the rostrum is elongated in many of the ones ive found lately. They look quite a bit different from the calymenids I usually find at this spot. I need some help with the ID since I havent seen any like this before.

 

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Cumings & Shrock reported Calymene niagarensis and Diacalymene (=Calymene) vogdesi from Liston Creek.

 

Cumings, E.R., & Shrock, R.R. 1928

The geology of the Silurian rocks of northern Indiana.

Indiana Geological Survey Publication, 75:1-226

 

The Liston Creek calymenids are in limbo: Sthenarocalymene? sp. (figs. 10-13) & Calymene sp.  

Sthenarocalymene is a junior synonym, so they are Calymene sp. awaiting further description.

 

figures from:

 

Edgecombe, G.D., & Adrain, J.M. 1995
Silurian Calymenid Trilobites from the United States.
Palaeontographica Abt.A, 235:1-19

 

image.thumb.png.5865237770e69a1b73a6048ca8b24c1d.png

image.png.a84de26dad44fb03836a743755df237c.png

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6 minutes ago, piranha said:

Cumings & Shrock reported Calymene niagarensis and Diacalymene (=Calymene) vogdesi from Liston Creek.

 

Cumings, E.R., & Shrock, R.R. 1928

The geology of the Silurian rocks of northern Indiana.

Indiana Geological Survey Publication, 75:1-226

 

The Liston Creek calymenids are in limbo: Sthenarocalymene? sp. (figs. 10-13) & Calymene sp.  

Sthenarocalymene is a junior synonym, so they are Calymene sp. awaiting further description.

 

figures from:

 

Edgecombe, G.D., & Adrain, J.M. 1995
Silurian Calymenid Trilobites from the United States.
Palaeontographica Abt.A, 235:1-19

 

image.thumb.png.5865237770e69a1b73a6048ca8b24c1d.png

 

Any idea how big these specimens pictured are? 

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1 hour ago, andyrice11 said:

Any idea how big these specimens pictured are? 

 

 

The actual page size of the figures is ~75% of the full size posted image.  In the plate descriptions the figures are 2-2.5X enlarged.  The complete prone specimen appears to be 5 cm+

image.png.a84de26dad44fb03836a743755df237c.png

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