Horizon and locality: Linton, Ohio, Coal Measures.
The specimens of this species indicate that the form was only about half the size of Ptyonius pectinatus. The interclavicle is narrower and more reticulately sculptured. The tail is relatively longer. Abdominal rods hair-like. Ribs distinct. Small limbs are present in one specimen.
| Measurements of Cope's Type of Ptyonius serrula. | |
| mm. | |
| Length of specimen | 95 |
| Length of portion of skull preserved | 3 |
| Length of interclavicle | 4.5 |
| Width of interclavicle | 2 |
| Length of clavicle | 4 |
| Width of clavicle | 1.5 |
| Length of vertebra | 1 |
| Width of vertebra from tip of neural spine to tip of hæmal spine | 4 |
Another specimen ([456 G, American Museum of Natural History]) shows some of the same characters. There is not the slightest basis for the support of this species, so far as I can observe. The ones mentioned by Cope are insufficient. It is in all probability a mutant or variety of Ptyonius pectinatus.
Genus ŒSTOCEPHALUS Cope, 1868.
Cope, Proc. Phila. Acad. Nat. Sci., 218, 1868.
Cope, Trans. Amer. Phil. Soc., XIV, 16.
Cope, Proc. Phila. Acad. Nat. Sci., 1868, 217.
Cope, Proc. Amer. Phil. Soc., 1871, 41.