1952  Prothalassoceras umbilicatum Ruzhentsev: 59,  text-fig.13-14, pl.1 fig.8,9, pl.6 fig.1.
     1986  Prothalassoceras umbilicatum.-Bogoslovskaia: 60, pl.39 fig.2, pl.56 fig.15.

Fig. TAX3887 A-B (sutures), C (cross-section).