| Citation | Romanov, V.N., 1989 Fauna of USSR. Tunicates. Vol. 1, No. 1. Ascidians. Colonial ascidians of the family Didemnidae from the seas of the USSR and adjacent waters. Fauna SSSR (138):1-224. |
| Ref. | 7499 Romanov, V.N., 1989 |
| Page | |
| Named Used as Valid | Didemnum extensum |
| Locality | |
| Distribution | Russia. |