Waldron Shale Cystoid Holdfasts?

 

On September 21, 2020, I posted this fossil but was unsure what exactly it was. After consulting with my cousin Kenny and Ken (a Waldron Shale fossil hunter of over 40 years), I am leaning toward and identification that this fossil is a cluster of cystoid holdfasts.

Kenny showed me a paper entitled Taphonomy of diploporite (Echinodermata) holdfasts from a Silurian hardground, southeastern Indiana, United States:palaeoecologic and stratigraphic significance by James R. Thomka and Carlton E. Brett published in 2014 at Geol. Mag. 151 (4) in 2014 pages 649-665. It shows a variety of fossils similar to the one pictured that are thought to be parts of Silurian cystoid fossils.

A link to that paper is here:

http://webcentral.uc.edu/eprof/media/attachment/eprofmediafile_2376.pdf

The fossil was found the Silurian Period (Wenlock: Homerian Stage) in Clark County Indiana, USA. If this fossil is a series of holdfasts, then they grew in close proximity to one another.

I have found numerous cystoids in the Waldron Shale notably Caryocrinites (Say, 1825) and Holocystites (Hall 1864) aka Megacystites (Hall, 1865). See previous entries:

https://louisvillefossils.blogspot.com/2010/06/holocystites-cystoid.html

https://louisvillefossils.blogspot.com/2011/08/caryocrinites-cystoid-in-matrix.html

https://louisvillefossils.blogspot.com/2011/10/caryocrinites-persculptis-cystoid.html

https://louisvillefossils.blogspot.com/2012/05/pyrite-encrusted-caryocrinites-cystoid.html

https://louisvillefossils.blogspot.com/2012/12/silurian-caryocrinites-cystoid-fossil.html

Cheiropteraster giganteus Brittle Star Fossil

 

The image shown above is brittle star echinoderm fossil called Cheiropteraster giganteus (Stürtz 1890). This animal fossil dates to the Early Devonian Period between 409 and 403 million years ago of the Paleozoic Era. While not labeled the fossil was probably found in Germany.

The fossil was on display in the entrance way of The Field Museum of Natural History in Chicago Illinois, USA as of August 2020. Accession number is P 1029.

I believe the genus and species was named by Bernard Stürtz (1845-1928) in 1890.

Mortoniceras leonensis Ammonoid Fossil

 

The image shown above is ammonoid mollusk fossil called Mortoniceras leonensis (T.A. Conrad, 1857). This animal fossil dates to the  Late Maastrichtian Stage, Cretaceous Period between 144 and 65 million years ago of the Mesozoic Era. It was found Texas, USA. 

The fossil was on display in the Evolving Planet section of The Field Museum of Natural History in Chicago Illinois, USA as of August 2020. Accession number is PE3908.

Species named by Timothy Abbott Conrad (1803-1877).