Fossil specimen (internal mold) of the brachiopod *Pentamerus oblongus* from the Silurian Waukesha Limestone of Jackson County, Iowa (PRI 70761). Specimen is from the collections of the[ Paleontological Research Institution](http://www.priweb.org), Ithaca, New York. Longest dimension of specimen is approximately 7 cm. Note that half of the specimen (anterior half) is missing. Model by Emily Hauf.