Catalog Number: CG-0032

Update:
This specimen is Allopinna godleskya Yancey 2024.
-Clint August 2024

I’m not certain about the genus and species. I’ve considered Meekopinna Americana and Aviculopinna peracuta as possibilities. However, upon reading an article from the Journal of Paleontology, the entire family needs some clarification.

We understand, however, that the Paleozoic Pinnidae are in need of a complete re-investigation; hence we only cautiously designate the material described here under Meekopinna and Aviculopinna.

L. E. Anelli, A. C. Rocha-Campos, M. G. Simoes; Pennsylvanian Pteriomorphian bivalves from the Piaui Formation, Parnaiba Basin, Brazil, JOURNAL OF PALEONTOLOGY, V. 80, NO. 6, 2006

From the size of the cross-section in this specimen, I will have to go with Aviculopinna peracuta for now. It’s a very wide oval in size in cross-section. It comes from my local limestone and is approximately 305 million years old. Sea pens are easy to find locally. They often are the point where limestone will shear when struck. They appear as distinct pointed ovals on the surface and typically stand up, with the smaller point directly towards the ground. The shell material will often stick to the rock it came from, leaving the distinct grooves from where it came.

Specimen is about 60mm in length. It was broken in half, I glued it back together using Paraloid B-72
Aviculopinna peracuta
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Fossil Prismatic Layer

I’ve done an entire posting relating to the prismatic layer in Sea Pens. This one shows the layer well. It appears as tall spines of material aligned towards the surface. These photos show it.

The prismatic later is on the top, followed by a calcite layer that is about twice the thickness. I suspect the prismatic layer has been fossilized as calcite as well.

Specimen Dimensions

Aviculopinna peracuta

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