Thursday, February 25, 2010

Acidaspis? Trilobite Fragments

After an earlier interpretation that these fossils may be worm jaw fragments, I have been pointed in the direction that these are trilobite fragments. It appears that the Kope Formation of the Upper Ordovician Period has some other small trilobites than just the Cryptolithus.  Two other tiny trilobites found in this formation are the Acidaspis and Meadowtownella (aka Primaspis)The trilobites appear to be related to each other and were quite small and spiny.  These fragments all show small bumps and broken spines on their edges.  See Marc Behrendt article Trilobites of the Cincinnati Region on his website.

Also check out the Dry Dredgers website of Dan Cooper's Acidaspis photos at this web page.

Meadowtownella (aka Primaspis) trilobite images are on the Dry Dredgers website as well at this web page.

All images while not labeled are at 40x magnification.





Fossils were found in Carroll County, Kentucky.


Anonymous said...

The third pic is a ventral. How about a dorsal?

But, yep. Acidaspis sp., not Primaspis sp.

Sippin corn, Solius.

Kentuckiana Mike said...

Thanks for the input. I have now screened the Kope Formation material and did not find any pygidium material (that I know of).

I did send two pieces to the ASPEX for imaging with the SEM. Time will tell if they will image it or not.