Kallidecthes richardsoni
Class Crustacea, Order Aeschronectida
Geological Time: Pennsylvanian (~300 million years ago)
Size (25.4 mm = 1 inch): Fossil is 37 mm long ; Matrix: 50 mm by 28 mm and 50 mm by 23 mm nodule pair
Fossil Site: Mazon Creek, Pit 11, Francis Creek shale, Braidwood, Illinois
Code: CBF05
Price: Sold
 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. This specimen is of a genus that represents an entirely
extinct radiation of crustaceans that went extinct, leaving the
modern-day mantis shrimps as closest relatives. Large examples
such as this that possess a deeper abdomen and more rectangular
carapace may actually represent a distinct species. |
