Fossil Friday

A fossil!

From the wheat penny provided for scale, the Fossil Friday Irregulars will instantly infer that the photograph was provided by Dan Phelps and surmise, moreover, that the fossil was found in Kentucky. Absolutely. If I add a little jargon about its provenance—that it was found in a phosphatic nodule in the New Providence Member of the Borden Formation of the lower Carboniferous—will you be able to tell me, if not the exact species, at least the clade? What if I mentioned that the clade exemplifies the phrase “pearls before swine”? The first person to correctly identify it in the comments section below will be excused from kitchen duty at NCSE's office for a month.