First oncocerid cephalopod from Japan

Abstract

The two Lochkovian (Early Devonian) specimens of karocerartid cephalopod from the Fukuji Formation, Gifu Prefecture represent the first record of the order Oncocerida in Japan, and constitute the basis for a new species, Ankyloceras takii. This species is morphologically closest to Ankyloceras accomodatum Zhuravleva and A. virgulaforme (Foerste) both from the early Lochkovian of Novaya Zemlya. Paleobiogeographic implications of the present discovery are discussed.

(Communicated by Tatsuro MATSUMOTO, M. J. A., April 14, 2003)