Heyuanoceras or Heyuan Ammonite
The heyuan ammonite is a type of Ladinian ammonite fossil (late stage of the Middle Triassic). These fossils have been mined in Zeng Keng Village in Shuangjiang Town, Dongyuan County, Heyuan City, Guangdong Province. The fossils excavated in Zeng Keng generally have sizes of approximately 1–10 cm, but the largest was 42 cm in diameter and was appraised as China’s best fossil of this kind. The ammonite fossil mine relics at this site cover an area of approximately 20 m2, Coroniceras is the main fossil type, and Paracoroniceras is the secondary type.