This is the “Fossil Friday” post #286.  Expect this to be a regular feature of the website.  We will post fossil pictures you send in to esconi.info@gmail.com.  Please include a short description or story.  Check the #FossilFriday Bluesky/Twitter hash tag for contributions from around the world!

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For this week’s Fossil Friday, we have a Rhabdoderma exiguum. R. exiguum is a species of Mazon Creek coelacanth.  Coelacanths are lobe-finned fish, thought extinct since the Cretaceous.  The first living coelacanth was discovered in 1938 off the coast of South Africa. There are now two known living species.

Rhabdoderma exiguum was described by Charles R. Eastman (1868 – 1918) in 1902. Eastman was an American geologist and paleontologist, who specialized in fish.  The paper “The Carboniferous Fish-Fauna of Mazon Creek, Illinois”, which was published in The Journal of Geology.   He named it Coelacanthus exiguus. For more information, see Mazon Monday #214.

This specimen was collected from the Northern portion of Pit 11 by Judy Dedina in May 1979. Judy served as club historian for many years amd was active in the Mineral and Paleontology study groups. Her sister Kathy was president from 1989-1990.  Additionally, Kathy served in other capacities for the club over the years, such as Vice-President, Treasurer, and Recording Secretary. In the photo below, Kathy is on the far left and Judy is on the far right.

And, now on to the fossil…