This is Mazon Monday post #198.  What’s your favorite Mazon Creek fossil?  Tell us at email:esconi.info@gmail.com.  Thanks!

---

We have a very rare little gem from Mazon Creek for our Fossil Friday this week. Smithixerxes juliarum is one of the rarest of Mazon Creek animals.  It belongs to a group of extinct arthropods called the euthycarcinoids.  They lived from the Cambrian to the Triassic.  Euthycarcinoids may have been amphibious. 

Smithixerxes juliarum was described by Frederick Schram and W. D. Ian Rolfe in the paper “New Euthycarcinoid Arthropods from the Upper Pennsylvanian of France and Illinois”, which was published in the Journal of Paleontology in 1982.  S. juliarum was named for the specimen collected by Karlene Helmus Ramsden for her then one-day-old niece Julia Smith; and for Julia Rayer Rolfe, spouse of the junior author of the paper.

This little beauty comes from ESCONI member Jake Fill.  He collected it from Pit 11 in the spring of 2023.  It opened via freeze/thaw in June of 2023.   Thanks for sharing, Jake!