Monday, May 10, 2010

Silurian Crinoid Arm/Stem? - Myelodactylus convolutus



This appears to be a Myelodactylus convolutus arm/stem found in Clark County, Indiana, USA in the Waldron Shale.  The fossil is from the Middle Silurian Period (around 425 to 419 million years ago).  High hopes that sand blasting will reveal more details of this fossil including the pinnules or feather looking part of the arm.

UPDATE (2020/02/16): Original post had this as unknown, but thanks to Kenny and ID has been found. Also this specimen was cleaned some more, see this posting https://louisvillefossils.blogspot.com/2010/06/silurian-crinoid-arm.html

Learn more about this unique crinoid from this article Myelodactylid crinoids from the Silurian of the British Isles by Stephen K Donovan and George D Sevastopulo from 1989 Palaeontology Volume 32 pages 689-710 at https://www.biodiversitylibrary.org/part/173971#/summary Plate 81 shows clear examples of what the calyx looked like though it might be somewhat different in the species of this fossil.

2 comments:

Anonymous said...

At first, I thought that it was a cirri, but when I "opened" the photo, I noticed the pinnate structure. It will be interesting to see how it preps out.

Kentuckiana Mike said...

I am wondering if it belongs to an Eucalyptocrinites crinoid since that is what the Waldron Shale is known for.

Hoping the matrix is pretty soft for the sand abrasion to quickly reveal more details.