[1] The Grypoceratidae are characterized by evolute to involute shells that may have some modification to the venter (the outer rim) varying from flattened to subangular, or bearing a keel.

Whorl sections are generally compressed but may be subquadrate to subtrapezoidal or coronate (heart shaped), or slightly depressed dorso-ventrally.

[2][1] The Grypoceratidae begin with Epidomatodceras from the Lower Carboniferous (Mississippian), an evolute form with a smooth shell, subquadrate whorl section, and a sharp angular ventral lobe in the suture.

Gryponautilus from the Upper Triassic is broadly involute with a narrowly rounded, keel-like venter at maturity and shallow ventral and lateral lobes in the suture.

The Grypoceratidae of Shimansky contains the Triassic genera of Kummel's larger Grypoceraidae and are derived, probably in the Late Permian, from the more restricted Domatoceratidae.