This genus is known in the fossil record from the Jurassic to the Eocene (from about 175.6 to 37.2 million years ago). Fossils of species within this genus have been found in Europe, Canada, China, Colombia (Coquina Group, La Guajira), Pakistan, Paua New Guinea, Thailand, Japan, Somalia, Nigeria, Iran, Tanzania, Algeria, Tunisia, Egypt, Madagascar, Russia, Ukraine, Uzbekistan, Venezuela and Chile.[1]