†Pirikia Hatai & Noda 1975

Hatai & Noda 1975. A new Problematica from the 'Pliocene Hanaishi Conglomerate member of the Chinkope Formation at Pirika, Setana-Gun, southwest Hokkaido, Japan. Proceedings of the Japanese Society for Systematic Zoology, No. 11 1975: 17-22