| 1973. | Cymatium (Ranularia) subpyrum (Yokoyama, 1920) Paralectotype Oyama, K. 1973 p. 37, pl. 9, fig. 5 |
| 1954. | Cymatium (Ranularia) subpyrum (Yokoyama, 1920) Paralectotype Taki, I. & Oyama, K. 1954 pl. 5, fig. 4 |
| 1920. | Triton subpyrum Yokoyama, 1920 Syntype Yokoyama, M. 1920 p. 65, pl. 4, fig. 4 |
| Condition: | Present |
| Taxonomy: | Mollusca: Gastropoda: Ranellidae: |
| Geologic Time: | Cenozoic: |
| Horizon: | Naganuma Formation: |
| Locality: | Kanagawa: Tostuka-ku, Yokohama: Naganuma: |
| Oyama, K., 1973: Revision of Matajiro Yokoyama's type Mollusca from the Tertiary and Quaternary of the Kanto area. Palaeontological Society of Japan, Special Papers, no. 17, pp. 1–148, pls. 1–57. (Reference No. 0411) |
| Taki, I. and Oyama, K., 1954: Matajiro Yokoyama's the Pliocene and later faunas from the Kwanto region in Japan. Palaeontological Society of Japan, Special Papers, no. 2, pp. 1–68, pls. 1–49. (Reference No. 0441) |
| Yokoyama, M., 1920: Fossils from the Miura peninsula and its immediate north. Journal of the College of Science, Imperial University of Tokyo, vol. 39, art. 6, pp. 1–193, pls. 1–20. (Reference No. 0464) |
  |
| Ichikawa, T., 1983, no. 9, p. 120. |
| Ichikawa, T., 1983, no. 9, p. 188. |
| Ichikawa, T., 1983, no. 9, p. 254. |
