Ammonite - Hyperlioceras

myminifactory

Hyperloceras is a long-extinct genus of cephalopod belonging to the ammonite family Graphoceratidae that thrived during the Bajocian stage of the Middle Jurassic. The type species is Hyperlioceras discites. The shell of Hyperlioceras is extremely compressed and involute, featuring a tall persistent keel and a deep umbilicus. The International Commission on Stratigraphy (ICS) has defined the base of the Bajocian Stage as the lowest occurrence of the genus Hyperloceras at 170.3 ± 1.4 million years ago, marking the start of the Hyperlioceras discites Zone. This point also signals the end of the preceding Aalenian stage. The upper boundary of the Bajocian is indicated by the lowest occurrence of the ammonite Parkinsonia (G.) convergence at approximately 167.7 Ma, defining the base of Zigzagiceras zigzag Zone. This object was discovered through Fossils in Shropshire.