Type species: Fenestralia permiana Nikiforova, 1936(1940?)
This genus includes the species:
| Triznella formosa | Morozova, 1963 | Permian Guadalupian | Russia Russian Platform |
| Triznella permiana | (Nikiforova, 1936) | Permian Guadalupian | Russia Russian Platform |
| Triznella viatkensis | (Nikiforova, 1936) | Permian Guadalupian | Russia Russian Platform |
Thanks to A. Ernst for corrections.