Fossil specimen of the shrimp-like crustacean *Belotelson magister* from the Pennsylvanian Mazon Creek lagerstätte of Will County, Illinois. Specimen is from the collections of the [Paleontological Research Institution](http://www.priweb.org), Ithaca, New York. Specimen is preserved inside a concretion. Length of specimen (not including surrounding rock) is approximately 4.5 cm. Model by Emily Hauf.