Species in this family can typically grow large to very large (over 30 cm), are relatively flat, have an inverted egg-shaped outline, opisthoparian sutures, a glabella that in early genera has parallel sides and expands forward in later representatives, and approaches or reaches the frontal border.
Species in this family can usually grow to be very large (over 30 cm), are relatively flat, have an inverted egg-shaped outline, opisthoparian sutures, a glabella that initially has parallel sides and expands forward in later representatives, and approaches or reaches the frontal border.