1898  Glyphioceras beyrichianum var. praematura Haug: 98,
           pl.1 fig.12,13,14.
     1938  Homoceras beyrichianum praematurum.-Demanet &
           STraelen: 180, pl.132 fig.13,14.
     1971  Isohomoceras praematurum.-Ruzhentsev & Bogoslovakaya:
           pl.3 fig.1.
     1978  Isohomoceras praematurum.-Ruzhentsev & Bogoslovskaya:
           189, pl.13 fig.1-5.
 
Fig. TAX2393 A-D (sutures).