Isognomon donated to Delaware Museum of Natural History

[I_gotta_rock]

In 2008, I found one of the prizes of my collection amongst a pile of sand and broken bits at Calvert Cliffs. I knew from seeing museum specimens of Isognomon maxillata that even with the tip broken off, this was a great find.  After admiring it on my shelf every day since, I decided to share it. Today it has a new home at the Delaware Museum of Natural History, which did not have any of this species or much of anything from that region amongst its 2,000,000+ mollusk specimens. Along with the Isognomon, I donated a Chesapectin nefrens shell with a number of pearl buds on the inside and a Tongue shell (Glossus santamaria) from the same location. 

 

The curator was happy to tell me that after 40 years of displaying modern sea shells and fossils of dinosaurs, they are finally putting together an exhibit of fossilized sea shells. Who knows, maybe one or more of these will end up on public view?

[fossiling]

nice!

[MikeR]

Your shell has been traditionally called Isognomon maxillata (Lamarck, 1819).   Ward (1992) classified all Miocene Mid-Atlantic Isognomon as Isognomon (Hipppochaeta) sp. since several species could be represented throughout the Miocene, but noted that since nearly all specimens are fragmentary, it would need additional study to verify.  Kidwell et. al. (2015) identified Hippochacaeta maxillata in the Drumcliff Member of the Choptank Formation.  I don't know if that is based on precedence or if the original shell described by Lamarck came from Shattuck Zone 17, but since Chesapecten nefrens is restricted to the Choptank, any of these names for your oyster would probably suffice.

 

Mike

[Caverat]

Thanks for helping me identify this specimen found at Calvert Cliffs 27 June 1992 . The light Blue grid is one inch.