Supplementary description of the ammonoids from the Barremian to the Albian of the Choshi Peninsula, Japan

Seven Barremian ammonoid species and two Aptian species from the Choshi Group, Japan, are described here. Among the Barremian forms, new species of Holcodiscus and Pulchellia are proposed. Furthermore, three Albian ammonoid species are also described as derived Cretaceous fossils mainly from the Miocene Naarai Formation. The Choshi fauna shows a high similarity to that of the Mediterranean region of the Tethyan realm (Obata and Matsukawa, 2007). All the described species of ammonoids from the Choshi Peninsula are listed and their geological ages are discussed.