Turritella importuna Yokoyama, 1924
| 1960. | Turritella importuna Yokoyama, 1924 Syntype Oyama, K. et al. 1960 p. 38, pl. 3, fig. 7a |
| 1957. | Turritella importuna Yokoyama Syntype Makiyama, J. 1957 pl. 11, fig. 6 |
| 1924. | Turritella importuna Yokoyama, 1924 Syntype Yokoyama, M. 1924b p. 10, pl. 1, fig. 6 |
| Condition: | Missing |
| Taxonomy: | Mollusca: Gastropoda: Turritellidae: |
| Geologic Time: | Cenozoic: Oligocene: |
| Horizon: | Shiramizu group: Asagai formation: |
| Makiyama, J., 1957: Matajiro Yokoyama's Tertiary fossils from various localities in Japan. Part 1. Palaeontological Society of Japan, Special Papers, no. 3, pp. 1–4, pls. 1–24. (Reference No. 0367) |
| Oyama, K., Mizuno, A. and Sakamoto, T., 1960: Illustrated handbook of Japanese Paleogene molluscs., pp. 1–244, pls. 1–71. Geological Survey of Japan. (Reference No. 0412) |
| Yokoyama, M., 1924b: Molluscan remains from the lowest part of the Jo-ban coal-field. Journal of the College of Science, Imperial University of Tokyo, vol. 45, art. 3, pp. 1–22, pls. 1–5. (Reference No. 0472) |
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| Ichikawa, T., 1983, no. 9, p. 156. |
| Ichikawa, T., 1983, no. 9, p. 40. |
| Ichikawa, T., 1983, no. 9, p. 302. |
