Harpoceras ( Harpoceras ) okadai (Yokoyama)
| 1971. | Harpoceras (Harpoceras) okadai (Yokoyama) Holotype Hirano, H. 1971 p. 127, pl. 20, fig. 1 |
| 1904. | Grammoceras ? Okadai Yokoyama Holotype Yokoyama, M. 1904b p. 14, pl. 4, fig. 3 |
| Condition: | Present |
| Taxonomy: | Mollusca: Cephalopoda: |
| Geologic Time: | Mesozoic: |
| Hirano, H., 1971: Biostratigraphic study of the Jurassic Toyora group. Part 1. Memoirs of the Faculty of Science, Kyushu University, Series D, vol. 21, no. 1, pp. 93–128, pls. 14–20. (Reference No. 0047) |
| Yokoyama, M., 1904b: Jurassic ammonites from Echizen and Nagato. Journal of the College of Science, Imperial University of Tokyo, vol. 19, art. 20, pp. 1–17, pls. 1–4. (Reference No. 0331) |
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| Ichikawa, T. and Hayami, I., 1978, no. 2, p. 42. |
| Ichikawa, T. and Hayami, I., 1978, no. 2, p. 301. |
