Cope, Geol. Surv. Ohio, II, pt. II, pp. 374, 375, pl. xli, figs. 2 and 3, 1875.
Moodie, Bull. Am. Mus. Nat. Hist., XXVI, p. 356, pl. 63, fig. 3, 1909.
Type: Specimen No. 8546 G, American Museum of Natural History. No. 8614 G, same museum, is associated with the type specimen.
Horizon and locality: Linton, Ohio, Coal Measures.
Two well-preserved individuals display peculiarities which indicate specific distinctness from the previously known species of Ptyonius. The abdominal rods are of the coarse type of those of P. marshii. The caudal fans are well developed, and not so wide as in P. pectinatus. The interclavicle is a discoid body of different form from that of P. marshii and I can not detect the clavicles. The sculpture consists of strong ridges, which radiate from the center to near the border. Immediately in front of this interclavicle is the head, which has a different form from that of the other known species. The interorbital width is two-thirds the long diameter of the orbit. The structure of the skull can not be made out. A slender, elongate hind limb is present in the second specimen, and a humerus is well preserved in the type.
| Measurements of the Type of Ptyonius nummifer Cope. (No. 8546 G, American Museum of Natural History. No. 8614 G is associated in the same species.) | |
| mm. | |
| Length to beginning of caudal fans | 65 |
| Length of head | 15 |
| Length from muzzle to orbits | 6 |
| Length of interclavicle | 7 |
| Width of interclavicle | 8 |
| Width of abdominal armature | 8 |
| Length of a caudal fan | 2.5 |
| Length of femur | 5 |
| Proximal width of femur | 1.5 |
Cope, Proc. Am. Phil. Soc., 1871, p. 177.
Cope, Geol. Surv. Ohio, II, pt. II, p. 379, pl. xxviii, fig. 5; pl. xxx, fig. 1, 1875.
Type: Specimen No. 8615 G, American Museum of Natural History.