Mezue ahịrịokwu na-esonụ: La Révellière-Lépeaux kpọrọ Renou na Paris na 1798, ebe e kwere ka ọ nata ihe ndị sitere na National Museum of Natural History, gụnyere otu ìgwè nke azụ 12 fosil si Italy (Monte Bolca) site na
Bonaparte na 1797, nke ka dị na ha mbụ kpọọ.