This is the "Fossil Friday" post #84. Expect this to be a somewhat regular feature of the website. We will post any fossil pictures you send in to [email protected]. Please include a short description or story. Check the #FossilFriday Twitter hash tag for contributions from around the world!
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For the third time this year, we have a spider fossil for Fossil Friday. Spider fossils are very rare in the fossil record. Mazon Creek and the other deposits of similar age like ones in Southern Illinois, Indiana, Kansas, and Missouri have some of the earliest known specimens from the Carboniferous. For reference, spider-like animals evolved back in the middle Devonian around 380 million years ago.
Today's specimen belongs to Chuck Barlow and was up for sale at the recent MAPS expo in Springfield, IL. The fossil species is unidentified, but seems similar to species in the order Ricinulei, which do have living relatives. It's an amazing fossil with quite a bit of detail! Thanks for the contribution, Chuck!
Chuck lives in Knob Noster, where there is a fossil deposit contemporaneous with Mazon Creek, which dates to about 307 million years ago. Currently, the Knob Noster locality is thought to have resided across a large bay from the Mazon Creek locality. Both were just south of the equator in the tropical Pennsylvanian seas. The red dot below represents Wilmington, IL 300 million years ago. Looking at the outline of Missouri, Knob Noster is in the middle west portion of Missouri, just southeast of Kansas City.
Paleo Map from https://dinosaurpictures.org/
Fossils from Knob Noster are found in concretions just like Mazon Creek. The Matrix is quite a bit different, being much lighter.
