Esconichthys, A Putative Mazon Creek Larval Lungfish

Description: The Mazon Creek deposits of the region near Braidwood, Illinois rival the other famous Lagerstatten of the Burgess Shale, Solnhofen, and Liaoning for the variety of detailed life preserved. Many exquisitely-preserved specimens are found in the ironstone nodules that make up the deposits. The majority of collecting areas are the spoil heaps of abandoned coal mines, the most famous of which is Peabody Coal Pit 11. Pit 11 now serves as a cooling pond for the Braidwood nuclear power plant, but with over 100 other localities, specimens still come to light. Known to collectors as “blades”, these fish are hought to be the larval form of a lungfish, but its exact taxonomic affinities are still under discussion. It has even been proposed that they are larval amphibians. The genus derives its name from ESCONI, the acronym for Earth Science Club of Northern Illinois. What is intriguing about this one is the patterning to the body, possibly showing scales. The dark structures are neither eyes nor otoliths; their precise identification is as yet undetermined. Here is a nice part/counterpart specimen offered at an affordable price.