Mazon Creek Fossil Fauna
Eggs
Shark Egg Cases
Within the taxonomic realm, Paleaeoxyris has had two lives: first within the flora, and now among the fauna. Its discovery some 175 years ago amidst plant material in the Mazon Creek concretions, coupled with its resemblance to a Weeping Willow or Ash leaf, prompted early researchers such as Leo Lesquereux (1880) to classify it as a plant. Similar specimens were placed in the genera Vetacapsula, Spiraxis, Fayolia, and Spirangium; species were then erected in these genera. Not all authorities agreed. By 1888, a paper stating these fossils to be "eggs of Elasmobranch fishes" had already been published. Opinions remained divided until the relationship between Palaeoxyris and modern forms of spiral shark egg capsules was demonstrated by Zidek (1976).
Palaeoxyris prendelli
Palaeoxyris prendelli, K.Robitschek collection - Vermillion River, Herrin Coal roof shale
(slightly younger than the Francis Creek shale of the Mazon Creek area)
(slightly younger than the Francis Creek shale of the Mazon Creek area)
Palaeoxyris prendelli, A.Young collection - Mazon River, Morris, Illinois
Palaeoxyris prendelli, Lauer Foundation collection
J.Wittry collection - Mazon River, Morris, IL
Palaeoxyris prendelli, A.Young collection - Wilmington, IL
Palaeoxyris prendelli, A.Young collection - Wilmington, IL
Palaeoxyris prendelli, Milwaukee Public Museum collection - MPM VP377853
Palaeoxyris prendelli, Lauer Foundation collection (positive and negative halves)
Palaeoxyris prendelli, Milwaukee Public Museum collection - MPM VP377850.1
Palaeoxyris multiplicatum
Palaeoxyris multiplicatum with Euproops danae, K.Robitschek collection - Wilmington, IL
Palaeoxyris multiplicatum, Lauer Foundation collection
Palaeoxyris lewisi
Palaeoxyris lewisi, Milwaukee Public Museum - MPM VP377849
The Chicago Academy of Sciences collection
Palaeoxyris lewisi, Milwaukee Public Museum collection - MPM VP377851.1
Palaeoxyris sulcatus (or P. warei)
Palaeoxyris sulcatus, M.Angkuw collection - Pit 11, Braidwood, IL
A.Young collection - Wilmington, IL
Palaeoxyris carbonaria
Palaeoxyris carbonaria, The Field Museum collection (Note: this complete specimen is from Knob Knoster, Missouri.
The same age as Mazon Creek, it shows excellent anatomical detail including the collarettes).
The same age as Mazon Creek, it shows excellent anatomical detail including the collarettes).
Fish and Amphibian Eggs
Mazonova helmichnus
Mazonova helmichnus, Lauer Foundation collection
Mazonova helmichnus, J.Wittry collection
Mazonova helmichnus, Milwaukee Public Museum collection VP940.1, P28720, and P28715.2