Note the forward facing teeth in both the upper and lower jaws. The authors collected the only known complete skull and fins of this fish. The specimen is now at the Los Angeles County Museum of Natural History. Protosphyraena tenuis - A medium sized predatory fish with sickle shaped fins characterized by a moderately serrated leading edge. The serrations are not thickened in cross section as they are in P. pernicosa .
Pectoral fins are massive in both length and thickness.
This genus has a heavy skull, with large, conical, and hooked teeth. The remains of the jaws were often mistaken for marine reptiles such as mosasaurs. Pachyrhizodus minimus A small predatory fish sometimes found preserved with scales and internal structure. The lower jaw of Pachyrhizodus minimus . About 4 inches.