Ever since I figured out what they were, Allopinna godleskya have been a personal favorite of mine. In examining the remaining shell material in these fossils, I have seen the prismatic layer on the shell hinge in at least two specimens. The specimens below show the detail.
The layer in a specimen from May 2019
The layer from Sea Pen III (Allopinna godleskya)
Further Reading
- The Prismatic Layer of Pinna: A Showcase of Methodological Problems and Preconceived Hypotheses – By Yannicke Dauphin, Alain Brunelle, Kadda Medjoubi, Andrea Somogyi and Jean-Pierre Cuif – Minerals – Volume 8, Issue 9
- Yancey, T.E., 1978, Brachiopods and mollusks of the Lower Permian Arcturus Group, Nevada and Utah, Pt. 1, Brachiopods, scaphopods, rostroconchs and bivalves. American Paleontology Bulletins, 74(303), pp. 257–363
- Yancey, T.E., Amler, M., Raczyński, P., & Brandt, S., 2023, Rebuilding the foundation of late Paleozoic pinnid bivalve study (family Pinnidae). Journal of Paleontology, 97(1), pp. 140-151.
- Yancey, T.E., 2024, Revision of Late Paleozoic Pinnid Genera and North American Species of Bivalve Family Pinnidae, Paleontological Research Institution, p. 84
- Aviculopinna & Meekopinna – Our research article on local pinnids.
- Godlesky, C. N., 2024, Allopinna godleskya, a New Species of Pinnid from the Brush Creek Limestone of Parks Township, Glenshaw Formation, Conemaugh Group, Western Pennsylvania