Harpoceras okadai (Yokoyama)
| 1974. | Harpoceras okadai (Yokoyama) Takahashi, H. 1974c pl. J-2, fig. 9 |
| 1964. | Harpoceras okadai (Yokoyama) Shikama, T. 1964 p. 154, pl. 54, fig. 4 |
| 1957. | Harpoceras (s. s.) okadai (Yokoyama) Sato, T. 1957 p. 345, pl. 2, fig. 10 |
| Condition: | Present |
| Taxonomy: | Mollusca: Cephalopoda: |
| Geologic Time: | Mesozoic: |
| Sato, T., 1957: Biostratigraphie de la série de Shizukawa (Jurassique inférieur) du Japon septentrional. Journal of the Faculty of Science, University of Tokyo, Section 2, vol. 10, pt. 3, pp. 313–350, pls. 1–2. (Reference No. 0269) |
| Shikama, T., 1964a: Index fossils of Japan., pp. 1–287, pls. 1–80. Asakura Shoten, Tokyo. (in Japanese) (Reference No. 0618) |
| Takahashi, H., 1974c: Ammonoid fossils of Japan, 1 (Jurassic ammonites, 1 — Shizukawa group). Atlas of Japanese fossils, no. 35-205, 4 pp., pl. J-2. Tsukiji Shokan Publishing Co., Ltd., Tokyo. (in Japanese) (Reference No. 0622) |
| Ichikawa, T., 1988, no. 15, p. 184. |
| Ichikawa, T., 1988, no. 15, p. 160. |
| Ichikawa, T. and Hayami, I., 1978, no. 2, p. 250. |
